AHFS Class:

• Antibacterials 84:04.04

Generic Name(s):

• Clindamycin Phosphate

Clindamycin is a semisynthetic derivative of lincomycin.5,6,7,100

Acne Vulgaris

Clindamycin phosphate is used topically alone or in conjunction with benzoyl peroxide in the treatment of inflammatory acne vulgaris.1,178,179 In weighing the potential benefits of topical clindamycin therapy, the possibility of serious adverse GI effects associated with the drug should be considered.1 Therapy of acne vulgaris must be individualized and frequently modified depending on the types of acne lesions which predominate and the response to therapy. Topical anti-infectives, including clindamycin, generally are effective in the treatment of mild to moderate inflammatory acne. However, use of topical anti-infectives as monotherapy may lead to bacterial resistance;186,187 this resistance is associated with decreased clinical efficacy.186 Topical clindamycin is particularly useful when used with benzoyl peroxide or topical retinoids.186,187 Results of clinical studies indicate that combination therapy results in a reduction in total lesion counts of 50-70%.186

Bacterial Vaginosis

Clindamycin is used intravaginally as a vaginal cream or suppository100,101,102,103,104,105,107,109,114,115,120,131,132,133,145,176,177,180 or orally101,109,120,128,129,130 for the treatment of bacterial vaginosis (formerly called Haemophilus vaginitis, Gardnerella vaginitis, nonspecific vaginitis, Corynebacterium vaginitis, or anaerobic vaginosis).

Bacterial vaginosis is a noninflammatory vaginal syndrome characterized by replacement of the normal vaginal flora (predominantly hydrogen peroxide-producing Lactobacillus ) with a mixed flora including Gardnerella vaginalis , anaerobes (e.g., Bacteroides ureolyticus , Prevotella , Porphyromonas , Peptostreptococcus , Mobiluncus ), and Mycoplasma hominis ; vaginal discharge may be an unreliable indicator of infection since many women are asymptomatic.101,102,112,115,120,127,136,137 While Gardnerella previously was thought to be the sole causative agent of this syndrome, it currently is thought that bacterial vaginosis is a polymicrobial condition in which Gardnerella acts synergistically with anaerobic bacteria and genital mycoplasmas.101,102,132,136 Clinical diagnosis of the syndrome generally is established by characteristic vaginal manifestations rather than bacteriologic determinations.102,111,113,115,120,121,136 The presence of at least 3 of the following manifestations is considered diagnostic for bacterial vaginosis: a nonirritating, odoriferous, thin, homogeneous, grayish-white, noninflammatory vaginal discharge that smoothly coats the vaginal walls; a vaginal pH exceeding 4.5; the elaboration of malodorous amines (“fishy” odor) from discharge fluid after alkalinization with potassium hydroxide 10% (“whiff test”); and/or microscopic smears containing small coccobacillary organisms adherent to epithelial cells (“clue cells”).101,102,111,113,115,120,121,136,137,146 The presence of clue cells on wet mount examination of vaginal secretions is one of the most reliable indicators of bacterial vaginosis.113,147

Gram stain results consistent with a diagnosis of bacterial vaginosis include markedly reduced or absent Lactobacillus morphology and predominance of Gardnerella morphotype.100,102,113 Although Gram stain of vaginal secretions also has been employed as a diagnostic test for bacterial vaginosis, accuracy of this method depends on evaluation by an experienced microbiologist; thus, this technique is used more often in research and hospital settings whereas diagnosis by clinical criteria typically is performed in an office setting. 102,120,147,148 Gardnerella can be isolated from vaginal cultures in a large proportion of healthy women; because of this lack of specificity, culture for the organism is not recommended as a diagnostic method for bacterial vaginosis,101,102,115,120,136,153 and it is not used to guide therapy.100,102,115,136 The possibility of other pathogens commonly associated with vulvovaginitis or cervicitis (e.g., Trichomonas vaginalis , Chlamydia trachomatis , Neisseria gonorrhoeae , Candida albicans , herpes simplex viruses) generally should be ruled out,100 particularly since coinfection with these organisms may occur.102,147

Goals of treatment and recommended therapy for bacterial vaginosis differ for nonpregnant versus pregnant women.101 However, relief of signs and symptoms of infection is a principal goal of therapy, and all women with symptomatic bacterial vaginosis should be treated regardless of pregnancy status.101

Nonpregnant Women

The principal goal in the treatment of bacterial vaginosis in nonpregnant women is to provide relief of vaginal manifestations and signs of infection.101,102,120 Other potential benefits include a reduction in other infectious complications, including human immunodeficiency virus (HIV) infection or other sexually transmitted diseases.101 The US Centers for Disease Control and Prevention (CDC) states that treatment of bacterial vaginosis is indicated in all nonpregnant women who are symptomatic.101 The regimens recommended by the CDC for the treatment of bacterial vaginosis in nonpregnant women are a 7-day regimen of oral metronidazole (500 mg twice daily), a 5-day regimen of intravaginal metronidazole gel, or a 7-day regimen of intravaginal clindamycin cream.101 Alternative regimens recommended by the CDC for these women are a 7-day regimen of oral clindamycin or a 3-day regimen of intravaginal clindamycin suppositories.101

Intravaginal metronidazole therapy results in clinical cure rates comparable to those reported with a 7-day oral metronidazole regimen;105,106,107,110,114,131,133,139,140,145,154,177 intravaginal clindamycin cream appears to be less effective than the metronidazole regimens.101 The CDC suggests that intravaginal clindamycin is the preferred regimen for the treatment of bacterial vaginosis in women hypersensitive to metronidazole.101 Regardless of the therapy chosen, relapse or recurrence of bacterial vaginosis is common,101,102,114,115,120,132,136 and some clinicians suggest that an alternative regimen (e.g., oral therapy when intravaginal therapy was used initially) can be employed in such infections.101,120 Long-term maintenance therapy does not appear to be beneficial in women with recurrent or relapsing disease and is not recommended.101,120,153

Results of several controlled studies indicate that intravaginal clindamycin cream (3- or 7-day regimen) is more effective than placebo for the treatment of bacterial vaginosis.103,104,114,141,144,151 Results of some randomized, double-blind studies for the treatment of symptomatic bacterial vaginosis indicate that 5 g of clindamycin phosphate (2% clindamycin) vaginal cream (100 mg of clindamycin) applied daily for 7 days is as effective as oral metronidazole 500 mg twice daily for 7 days.105,106,107,114,131,145 Patients who were treated with this regimen of intravaginal clindamycin cream had cure rates or combined cure and improvement rates of 57-94% at 4-10 days following completion of therapy,103,104,105,107,114,145,151 and, in one study, a combined cure and improvement rate of 83% was observed at 1 month following completion of therapy in patients receiving intravaginal clindamycin cream compared with 78% in those receiving oral metronidazole;145 microbiologic response to therapy paralleled clinical response.103,104,107,151 In a randomized controlled trial, similar cure rates were obtained with intravaginal clindamycin cream (86%), oral metronidazole (84%), or intravaginal metronidazole gel (75%) at 7-14 days following completion of therapy; interpretation of these results is limited by the statistical limitations of this study (i.e., small sample size, inadequate power, short-term follow-up), and further study is needed to fully establish the comparative efficacy of these treatments.154 Results of randomized clinical studies indicate that cure rates obtained following a 3-day regimen of clindamycin vaginal suppositories are superior to placebo and comparable to those obtained with a 7-day regimen of oral metronidazole.177 Results of other studies indicate that cure rates obtained with a single 5-g dose of clindamycin phosphate vaginal cream (Clindesse^®) are superior to placebo and comparable to those obtained with a 7-day regimen of clindamycin vaginal cream (Cleocin^®).180 Long-term follow-up of patients suggests high recurrence rates for bacterial vaginosis regardless of initial therapy.101,106,114,145

Pregnant Women

An increased risk of obstetric complications, including intraamniotic infection, chorioamnionitis, premature rupture of membranes, preterm delivery, and low-birthweight infants, is associated with the presence of bacterial vaginosis in pregnant women,101,155,156,157,158,159 and the organisms found in increased concentrations in the genital flora of women with bacterial vaginosis are frequently found in patients with postpartum or postcesarean endometritis.160 Evidence from randomized, controlled trials indicates that systemic treatment of bacterial vaginosis reduces the rate of preterm birth in pregnant women at high risk for complications of pregnancy.101,161,162

Because of the increased risk of adverse pregnancy outcomes associated with the presence of bacterial vaginosis, the CDC recommends that all symptomatic pregnant women be tested and treated for bacterial vaginosis.101 In addition, because there is evidence from randomized studies that treatment of bacterial vaginosis in asymptomatic pregnant women at high risk for complications of pregnancy (e.g., those who previously delivered a premature infant) has reduced preterm delivery, some experts recommend that all women at high risk be screened and treated for bacterial vaginosis.101 The CDC recommends that screening for bacterial vaginosis (if conducted) should be performed at the first prenatal visit and treatment initiated if needed.101

The preferred regimens for the treatment of symptomatic bacterial vaginosis in pregnant women and for the treatment of asymptomatic women at high risk for complications of pregnancy are a 7-day regimen of oral metronidazole (500 mg twice daily or 250 mg 3 times daily) or a 7-day regimen of oral clindamycin (300 mg twice daily).101 Although some experts state that intravaginal therapy may be used solely for symptomatic relief (and not for prevention of adverse pregnancy outcomes) in women at low risk for preterm delivery,175 others prefer use of systemic therapy for all pregnant women, regardless of degree of risk for complications of pregnancy,101 because systemic treatment may be required to eradicate upper genital tract infection that may be associated with bacterial vaginosis.101,160,174 Use of intravaginal clindamycin to reduce preterm birth and treat bacterial vaginosis in pregnant women has been evaluated in several studies.101,163,164 In one study in women treated with intravaginal clindamycin early in the pregnancy (i.e., before 20 weeks' gestation), administration of clindamycin was associated with a reduction in preterm birth.101 In other studies, such therapy administered at 16-32 weeks' gestation did not reduce the incidence of adverse pregnancy outcomes.101,163,164 Therefore, the CDC states that intravaginal clindamycin should only be used during the first half of pregnancy.101

Women Undergoing Gynecologic Procedures and Surgery

The goal of treatment of symptomatic bacterial vaginosis in women undergoing hysterectomy or abortion is to reduce the risk of infectious complications (e.g., pelvic inflammatory disease [PID]) following these procedures.101

Treatment of asymptomatic bacterial vaginosis in patients who are about to undergo an invasive gynecologic procedure (e.g., endometrial biopsy, hysteroscopy, hysterosalpingography, hysterectomy, placement of an intrauterine device, uterine curettage), abortion, vaginal surgery, or abdominal surgery may be a reasonable consideration because of the association between this condition and various gynecologic infections (e.g., endometritis, PID, vaginal cuff cellulitis).101,115,119,120,136 While a reduction in postoperative PID in women with bacterial vaginosis undergoing first-trimester elective abortion has been established in at least one study employing oral metronidazole,119,120 further study is needed to determine the value of treating asymptomatic bacterial vaginosis in patients who are about to undergo other invasive procedures.120,147

HIV-infected Women

Recommendations for treatment and preferred regimens for bacterial vaginosis in patients with concurrent HIV infection are the same as those for patients without HIV infection.101

Sexual Contacts

Results of several randomized, double-blind, placebo-controlled trials indicate that concurrent treatment of male sexual contacts of a woman with symptomatic bacterial vaginosis generally does not appear to affect the clinical cure rate, including the risk of relapse or recurrence of the syndrome in the woman.101,167,168,169,170 Therefore, routine treatment of male sexual contacts currently is not recommended.101,102,111,120,136 However, despite the lack of controlled studies showing any benefit, some clinicians believe that treatment of male sexual contacts (with oral metronidazole) of women who have relapsing or recurrent bacterial vaginosis may be reasonable.115,132,136,169 Further study is needed to elucidate the possible role, if any, of sexual transmission in bacterial vaginosis.102,115,132,136,146,167

Administration

Clindamycin phosphate is applied topically to the skin1,178,179 or intravaginally100,176,180 in appropriate formulations.

Topical Administration

Clindamycin phosphate is applied topically to the skin as a gel, lotion, or solution containing clindamycin 1%.1 Clindamycin phosphate also is applied topically to the skin in the form of a gel containing clindamycin 1% in combination with benzoyl peroxide 5%.178,179 The gel, lotion, or solution should be applied to all areas of skin prone to acne.186

Topical preparations containing clindamycin phosphate are for external use only and should not be used orally or intravaginally and use near or in the eyes, nose, mouth, or mucous membranes should be avoided.178,179

The commercially available lotion containing clindamycin 1% should be shaken well immediately prior to use.1 The commercially available topical solution containing clindamycin 1% also is available in individual single-use pledget applicators.1 These pledgets should be removed from their foil immediately before use and should not be used if seal is broken.1 Each pledget should be used only once and then discarded; more than 1 pledget may be used for each application as needed to cover the affected area.1

The commercially available gel containing clindamycin phosphate in fixed combination with benzoyl peroxide (Duac^®) is applied topically as provided by the manufacturer.178

Alternatively, a combination topical gel containing clindamycin phosphate and benzoyl peroxide can be prepared at the time of dispensing (BenzaClin^®) by reconstituting clindamycin phosphate and admixing it with a gel containing benzoyl peroxide.179 After tapping the vial containing clindamycin phosphate provided by the manufacturer of BenzaClin^® to loosen the contents, 5 mL of purified water should be added to each vial containing 300 mg of clindamycin phosphate and the contents immediately shaken until the drug is completely dissolved.179 Additional purified water may be used if the contents do not reach the mark indicated on the vial.179 The clindamycin phosphate solution is then added to the benzoyl peroxide gel provided by the manufacturer and stirred for about 1-1.5 minutes until the gel appears homogeneous.179

Intravaginal Administration

Clindamycin phosphate is administered intravaginally as a vaginal cream containing 2% clindamycin or as a vaginal suppository containing 100 mg of the drug.100,101,103,104,105,107,114,131,145,180 Patients should be instructed in the use of the vaginal applicator and should be given a copy of the instructions provided by the manufacturer.100

Clindamycin phosphate vaginal preparations are for intravaginal administration only and should not be used orally, topically on the skin, or near or in the eyes.

Dosage

Acne Vulgaris

For the topical treatment of acne vulgaris, a thin film of the commercially available gel, lotion, or solution containing clindamycin 1% should be applied to the cleansed affected area twice daily.1 Alternatively, if the commercially available gel containing clindamycin 1% in fixed combination with benzoyl peroxide 5% as Duac^® is used for the topical treatment of acne vulgaris, a thin film of the gel is applied to the cleansed affected areas once daily in the evening or as directed.178 If the gel containing clindamycin 1% in combination with benzoyl peroxide 5% as BenzaClin^® is used for the treatment of acne vulgaris, a thin film of the gel is applied to the cleansed affected area twice daily.179

Maintenance therapy is needed to prevent recurrence.186

Bacterial Vaginosis

When Cleocin^® vaginal cream is used the treatment of bacterial vaginosis in nonpregnant women, one applicatorful (approximately 5 g) of clindamycin phosphate (2% clindamycin) vaginal cream (100 mg of clindamycin) is administered intravaginally once daily, preferably at bedtime, for 3 or 7 consecutive days.100,101,104,105,107,110,114,131,145 When Clindesse^® vaginal cream is used for the treatment of bacterial vaginosis, the usual dosage is a single applicatorful (approximately 5 g) of clindamycin phosphate (2% clindamycin) vaginal cream (100 mg of clindamycin) administered intravaginally.180 The US Centers for Disease Control and Prevention (CDC) recommends a 7-day regimen.101 Alternatively, one suppository containing 100 mg of clindamycin can be administered intravaginally, preferably at bedtime, for 3 consecutive days.101,176

In pregnant women, one applicatorful (approximately 5 g) of clindamycin phosphate (2% clindamycin) vaginal cream (100 mg of clindamycin) intravaginally once daily, preferably at bedtime, for 7 consecutive days, was an effective treatment for bacterial vaginosis but did not reduce the incidence of adverse pregnancy outcomes;163,164 thus, use of intravaginal clindamycin for the prevention of adverse pregnancy outcomes associated with bacterial vaginosis in women at high risk for preterm delivery is not recommended,101,175 and systemic treatment with oral metronidazole or oral clindamycin currently is preferred, particularly in pregnant women at high risk for complications of pregnancy.101,161,162,175 CDC states that clindamycin vaginal preparations should only be used during the first half of pregnancy.101

Clindamycin phosphate applied topically to the skin alone or in fixed combination with benzoyl peroxide generally is well tolerated.178,179 However, mild to moderate local effects may occur1,178,179 and systemic adverse effects (e.g., GI effects) have been reported rarely.1

Intravaginally applied clindamycin phosphate generally is well tolerated.103,105,107,110,114,131,145 Adverse effects occurred in about 10 or 20% of nonpregnant patients receiving intravaginal clindamycin phosphate suppositories or cream (3- or 7-day regimen), respectively, during clinical trials; discontinuance of the drug because of adverse effects was required in about 0.5 or 2-3% of patients receiving the drug as a suppository or cream, respectively.100,176 While systemically achieved concentrations of the drug generally are low at usual intravaginal dosages,100,108,176 this route of administration is not devoid of adverse systemic effects.100,110,176 Candidal infection (including vaginal or nonvaginal candidiasis and fungal infection, either symptomatic or confirmed by culture) has been reported in about 3 or 9-11% of nonpregnant patients receiving intravaginal clindamycin suppositories or cream, respectively.100,176

Local Effects

Topical Administration

The most frequent adverse effects of topical therapy with clindamycin phosphate 1% gel, lotion, or solution are dryness of the skin and erythema.1 In clinical studies evaluating the clindamycin phosphate 1% topical gel, lotion, or solution, dryness was reported in 23, 18, or 19% of patients, respectively, whereas erythema was reported in 7, 14, or 16% of patients, respectively.1 Oiliness or oily skin was reported in 18, 10, or 1% of patients receiving the topical gel, lotion, or solution, respectively.1 Peeling occurred in 7 or 11% of patients receiving topical clindamycin phosphate lotion or solution, respectively.1 In addition, burning or pruritus were reported in 7-11% of patients receiving these topical preparations of clindamycin phosphate.1

Commercially available clindamycin phosphate 1% topical solution contains alcohol which can burn and irritate the eyes.1 If clindamycin phosphate topical solution comes in contact with sensitive surfaces (e.g., eyes, abraded skin, mucous membranes), the surfaces should be bathed with copious amounts of cool water.1

In clinical studies evaluating the commercially available gel containing clindamycin phosphate 1% in fixed combination with benzoyl peroxide 5% (Duac^®), mild to moderate erythema was reported during treatment in 5-26%, dryness in 1-19%, peeling in 2-17%, and burning in up to 5% of patients.178 In clinical studies evaluating the gel containing clindamycin phosphate 1% in combination with benzoyl peroxide 5% that is prepared at the time of dispensing (BenzaClin^®), dry skin was reported during treatment in 12% and erythema, peeling, pruritus, or sunburn were reported in 1-2% of patients.179 The manufacturer states that patients in these studies were allowed to use moisturizers in conjunction with the gel and that the incidence of dry skin might have been greater if moisturizers had not been used.179

Genitourinary Effects

Intravaginal Administration

The most common adverse effects of therapy with clindamycin phosphate (2% clindamycin) vaginal cream or suppositories are vaginal candidiasis100,103,104,105,110,114,145,151 and vaginitis (including vulvovaginitis, vulvovaginal disorder, vaginal discharge, and trichomonal vaginitis).100,176

Because clindamycin is highly active in vitro against Lactobacillus 122,143,145 and metronidazole is inactive in vitro against most lactobacilli normally resident in the vagina,143,145 even at the high concentrations achieved with local application,143 it has been suggested that intravaginal application of clindamycin at usual concentrations may be more likely than intravaginal application of metronidazole to disrupt the normal vaginal flora.122,143 Limited evidence from a comparative study suggests that similar rates of vulvovaginal candidiasis occur following treatment with intravaginal clindamycin, intravaginal metronidazole, or oral metronidazole;154 however, further study is needed to establish the relative risk of this effect.147 In 2 unpublished comparative studies conducted by the manufacturer of metronidazole extended-release tablets, evaluation at 1 month following completion of therapy for bacterial vaginosis in nonpregnant women showed that vaginal pH and the balance of Lactobacillus in the vaginal flora were restored to normal in fewer patients receiving clindamycin phosphate vaginal cream than in those receiving oral metronidazole administered as extended-release tablets (65 versus 72% and 63 versus 74%, respectively), but the incidence rates of vulvovaginal candidiasis (12 versus 15%, respectively) did not differ.173 Approximately 1.5176 or 8-12%100,104,105,114,145 of nonpregnant women have been reported to develop vaginal candidiasis during or immediately following therapy with clindamycin phosphate vaginal suppositories or cream, respectively. 100,104,105,114,141,145,176 Higher cumulative frequencies of symptomatic vaginal candidiasis have been reported at 1 month following completion of intravaginal clindamycin phosphate cream therapy.105

Vaginitis (including vulvovaginitis, vulvovaginal disorder, vaginal discharge, and trichomonal vaginitis) has been reported in 3.6 or 9-10.7% of nonpregnant women receiving clindamycin phosphate vaginal suppositories or cream, respectively.100,103,105,114,131,145,151,176 Vulvovaginitis has been reported in 6 or 4.4% and vulvovaginal disorder (including irritation) has been reported in 3.2 or 5.3% of nonpregnant women receiving clindamycin phosphate vaginal cream for 3100 or 7 days, respectively.100,103,105,114,131,145,151 Vulvovaginal disorder or vaginal pain has been reported in 3.4 or 1.9%, respectively, of nonpregnant women receiving clindamycin vaginal suppositories.176 Trichomonas vaginalis infection reportedly occurs in 1.3% of nonpregnant women receiving clindamycin phosphate vaginal cream for 7 days.100 Vaginal discharge, metrorrhagia, urinary tract infection, pyelonephritis,176 dysuria,176 endometriosis, menstrual disorder, and vaginal pain each have been reported in less than 1% of patients receiving intravaginal clindamycin,100,176 and vaginal bleeding has been reported in at least one patient following use of clindamycin phosphate vaginal cream.105

Sensitivity Reactions

Topical Administration

Contact dermatitis has been reported in at least one patient following use of the commercially available clindamycin phosphate topical solution. The possibility that patients who become sensitized to topical clindamycin also may be sensitive to systemic clindamycin or lincomycin should be considered.

Intravaginal Administration

Urticaria, rash, application-site pain,176 and pruritus176 occur rarely in patients receiving intravaginal clindamycin.100,145,176

GI Effects

Topical Administration

Adverse GI effects including diarrhea, and less frequently, abdominal pain, bloody diarrhea, and colitis have been reported following topical application of clindamycin.1 In one survey, diarrhea reportedly occurred in less than 0.1% of 73,000 patients using extemporaneous preparations of clindamycin hydrochloride or clindamycin phosphate.

Clostridium difficile -associated diarrhea and colitis (CDAD; also known as antibiotic-associated diarrhea and colitis or pseudomembranous colitis) has been reported with the use of topical or systemic clindamycin.1,100,176,178,179,180

Intravaginal Administration

Heartburn, nausea, vomiting, diarrhea, constipation, and abdominal pain reportedly have occurred in patients receiving intravaginal clindamycin.100,105,114,141,145,151,176 CDAD, including fulminant pseudomembranous colitis, have been attributed to the use of intravaginal clindamycin.171,172

Other Adverse Effects

Intravaginal Administration

Dizziness, headache, flank pain,176 localized edema,176 and vertigo reportedly occur in less than 1% of patients receiving clindamycin phosphate vaginal cream or suppositories.100,145,176 Systemic candidiasis (excluding vaginal candidiasis) has been reported in 1.3 or 0.2% of nonpregnant women receiving clindamycin vaginal cream for 3 or 7 days, respectively.100

The possibility that other adverse effects reported with topical (e.g., contact dermatitis, erythema, irritation, peeling, oiliness, burning) or systemic clindamycin therapy could occur with intravaginal therapy or vice versa should be considered.100

Precautions and Contraindications

Topical or intravaginal use of clindamycin phosphate may result in overgrowth of nonsusceptible organisms.176 Treatment-related vaginal and nonvaginal candidiasis (moniliasis) and vaginitis (e.g., vulvovaginal disorder, vaginal discharge, vaginitis, vaginal infections) were reported in about 3-3.5% of nonpregnant women who received the drug in clinical studies for the treatment of bacterial vaginosis.176 In addition, gram-negative folliculitis has been reported rarely following topical use of clindamycin in the treatment of acne vulgaris. If suprainfection or superinfection occurs during clindamycin therapy, the drug should be discontinued and appropriate therapy instituted.

Patients receiving intravaginal clindamycin phosphate cream or suppositories should be instructed to not engage in vaginal intercourse100,105,176 and to refrain from use of vaginal products (tampons, douches)100,103,105,107,131,176 during the entire course of therapy since vaginal intercourse or vaginal products could reduce the efficacy of the preparations (e.g., by dislodgement and/or dilution, by increased vaginal pH secondary to deposition of semen).120,147 Because clindamycin phosphate vaginal cream and suppositories contain oleaginous bases (e.g., mineral oil) that may weaken latex or rubber products such as condoms or vaginal contraceptive diaphragms, such products may not be effective as contraceptives and/or microbial barriers if used within 72 hours following treatment with clindamycin vaginal cream (Cleocin^®) or suppositories (Cleocin^®).100,176 In addition, latex or rubber products such as condoms or vaginal contraceptive diaphragms may not be effective as contraceptives and/or microbial barriers if used within 5 days following treatment with clindamycin vaginal cream (Clindesse^®).180 Because clindamycin phosphate vaginal cream may cause ocular burning and irritation, contact with the eyes should be avoided.100 If such contact occurs, the manufacturer recommends that the eyes be irrigated with copious amounts of cool water.100,150

Because clindamycin is absorbed following topical or intravaginal application and because CDAD caused by overgrowth of toxin-producing clostridia has been reported with the use of topical or systemic clindamycin, it should be considered in the differential diagnosis of patients who develop diarrhea during or following topical or intravaginal clindamycin.1,100,176,178,179,180 Patients should be warned to discontinue use of clindamycin and to notify their clinician if GI symptoms such as diarrhea occur during topical or intravaginal therapy.1,100 Mild cases of colitis may respond to discontinuance of the drug alone, but diagnosis and management of moderate to severe cases should include appropriate bacteriologic and toxin studies and treatment with fluid, electrolyte, and protein supplementation as indicated.1,100,176,178,179,180,181,182,183,184,185 If colitis is severe or is not relieved by discontinuance of the drug, appropriate anti-infective therapy (e.g., oral metronidazole or vancomycin) should be administered.1,100,176,178,179,180,181,182,183,184,185

Clindamycin phosphate topical solution has an unpleasant taste, and caution should be used when applying the solution around the mouth.

The manufacturer states that clindamycin phosphate topical 1% gel, lotion, and solution should be used with caution in atopic individuals.1

Clindamycin phosphate 1% topical gel, lotion, and solution;1 gels containing clindamycin phosphate 1% in combination with benzoyl peroxide 5%;178,179 and clindamycin phosphate vaginal cream and suppositories100 are contraindicated in patients with a history of hypersensitivity to clindamycin, lincomycin, or any ingredient in the formulations. These topical and intravaginal preparations containing clindamycin phosphate also are contraindicated in patients with a history of regional enteritis, ulcerative colitis, or antibiotic-associated colitis.1,100,176,178,179

Pediatric Precautions

Safety and efficacy of clindamycin phosphate (clindamycin 1%) topical gel, lotion, and solution and topical gels containing clindamycin phosphate (clindamycin 1%) in fixed combination with benzoyl peroxide 5% in pediatric patients younger than 12 years of age have not been established.1,178,179

The manufacturer states that safety and efficacy of clindamycin phosphate vaginal cream (Cleocin^®) in children younger than 16 years of age have not been established.100,150 Safety and efficacy of the vaginal suppositories and clindamycin phosphate vaginal cream (Clindesse^®) in postmenarchal females have been established based on extrapolation of clinical trial data from adult women; safety and efficacy of the these preparations in premenarchal females have not been established.176,180

Geriatric Precautions

Clinical studies of topical or intravaginal clindamycin did not include sufficient numbers of patients 65 years of age or older to determine whether geriatric patients respond differently than younger patients.1,100,176,180

Carcinogenicity

Mutagenicity tests with clindamycin designed to assess genotoxicity (e.g., rat micronucleus test, Ames test) did not reveal evidence of mutagenic potential.100 Long-term studies in animals to determine the carcinogenic potential of topical or intravaginal clindamycin have not been performed to date.100

Pregnancy, Fertility, and Lactation

Pregnancy

Reproduction studies in pregnant rats and mice receiving oral and parenteral dosages of clindamycin up to 600 mg/kg daily (62 and 25 times, respectively, the maximum human dosage based on mg/m²) revealed no evidence of harm to the fetus.100 In one mouse strain, cleft palate was observed in fetuses of pregnant mice treated with clindamycin; this effect was not observed in other mouse strains or in other species.100

Intravaginal clindamycin has been used to treat bacterial vaginosis in pregnant women during the second and third trimester of pregnancy (for 7 nights of therapy).100,152 In one clinical study of pregnant women receiving clindamycin phosphate vaginal cream or placebo during the second trimester of pregnancy, abnormal labor was reported in about 1.1 or 0.5% of patients, respectively.100 Adverse effects have been reported in about 23% of pregnant patients receiving intravaginal clindamycin and have required discontinuance of the drug in about 2% of such patients.100 Candidal infection (including vaginal and nonvaginal candidiasis; either symptomatic or confirmed by culture) and vaginitis (including vulvovaginitis, vulvovaginal disorder, vaginal discharge, and trichomonal vaginitis) have been reported in about 13.3 and 7.2% of pregnant patients receiving clindamycin phosphate vaginal cream for 7 days.100 Vaginal candidiasis and vulvovaginal disorders occurred in 13.3 and 6.7%, respectively, of pregnant women receiving intravaginal clindamycin for 7 days while each of these adverse effects was reported in 7.1% of pregnant patients receiving placebo.100 Dysuria, metrorrhagia, vaginal pain, pruritus (at the application site), and trichomonal vaginitis occurred in less than 1% of pregnant patients receiving clindamycin phosphate vaginal cream.100 Other adverse effects reported in pregnant patients receiving intravaginal clindamycin include fungal infections and pruritus (in areas other than at the application site) in 1.7 and 1.1%, respectively; these effects were not reported in pregnant women receiving placebo.100 Upper respiratory infection and erythema were reported in less than 1% of pregnant women receiving clindamycin phosphate vaginal cream.100

There are no adequate and controlled studies to date using intravaginal100 clindamycin cream (Cleocin^®) during the first trimester of pregnancy or using clindamycin intravaginal suppositories or intravaginal clindamycin cream (Clindesse^®) during pregnancy;176,180 Clindamycin phosphate vaginal cream (Cleocin^®)100 should be used during the first trimester of pregnancy only when clearly needed, and intravaginal suppositories176 and intravaginal clindamycin cream (Clindesse^®)180 should be used during pregnancy only when clearly needed. In addition, because there are no adequate and controlled studies to date using topical preparations containing clindamycin phosphate (gel, solution, or lotion) or gels containing clindamycin phosphate in fixed combination with benzoyl peroxide during pregnancy, these preparations should be used during pregnancy only if clearly needed.1,178

Screening and/or treatment for bacterial vaginosis in pregnant women as clinically indicated should be conducted during the first prenatal visit.101 In one study in women treated with intravaginal clindamycin early in the pregnancy (i.e., before 20 weeks' gestation), administration of clindamycin was associated with a reduction in preterm birth.101 In other studies, such therapy administered at 16-32 weeks' gestation did not reduce the incidence of adverse pregnancy outcomes.101,163,164 For the treatment of bacterial vaginosis and reduction in the incidence of adverse pregnancy outcomes associated with bacterial vaginosis (e.g., preterm birth), particularly in pregnant women at high risk for complications of pregnancy, a 7-day regimen of oral metronidazole101,161,162,175 or a 7-day regimen of oral clindamycin is recommended.101 CDC states that clindamycin vaginal preparations should only be used during the first half of pregnancy.101

Fertility

Reproduction studies in rats and mice using subcutaneous or oral clindamycin in dosages of 100-600 mg/kg daily have not revealed evidence of impaired fertility or harm to the fetus.1 Reproduction studies in rats receiving oral clindamycin dosages up to 300 mg/kg daily (31 times the usual human dosage) have not revealed evidence of impaired fertility or mating ability.100

Lactation

Although it is not known whether clindamycin is distributed into milk following topical1 or intravaginal100 application, the drug is distributed into milk following systemic administration.1,100 Because of the potential for serious adverse reactions to clindamycin in nursing infants, a decision should be made whether to discontinue nursing or to discontinue topical or intravaginal application of the drug, taking into account the importance of the drug to the woman.1,100,178,179

Because clindamycin can be absorbed systemically following intravaginal application, the possibility that drug interactions could occur with this route of administration should be considered.100,108

Clindamycin has been shown to have neuromuscular blocking properties that may enhance the neuromuscular blocking action of other agents (e.g., ether, tubocurarine, pancuronium).100,125,126,176 Intravaginal100 clindamycin should be used with caution in patients receiving such agents100,125,126,176 and patients should be observed for prolongation of neuromuscular blockade.126

Topical acne preparations containing peeling, desquamating, or abrasive agents (e.g., benzoyl peroxide, tretinoin, salicylic acid, sulfur) should be used cautiously in patients using topical anti-infectives because a cumulative irritant effect could occur. In addition, information on the physical and/or chemical compatibility of topical anti-infectives and other topical acne preparations is not available. Concurrent use of abrasive or medicated soaps or cosmetic products containing alcohol (e.g., astringents, after-shave lotions) may also cause a cumulative irritant or drying effect in patients using topical anti-infectives.

Because of possible competitive binding for the 50S ribosomal subunit, clindamycin and erythromycin probably should not be used concomitantly.

Acute Toxicity

Topically applied clindamycin phosphate (gel, lotion, solution) or vaginally applied clindamycin phosphate (2% clindamycin) vaginal cream or suppositories can be absorbed in sufficient amounts to produce systemic effects.1,100,176

Mechanism of Action

Clindamycin may be bacteriostatic or bactericidal in action, depending on the concentration of the drug attained at the site of infection and the susceptibility of the infecting organism. Clindamycin phosphate is inactive until hydrolyzed to free clindamycin; phosphatases on the skin rapidly hydrolyze the drug following topical application.

Clindamycin appears to inhibit protein synthesis in susceptible organisms by binding to 50S ribosomal subunits; the primary effect is inhibition of peptide-bond formation. The binding sites of clindamycin appear to be the same as or to overlap those of chloramphenicol and erythromycin.

The exact mechanisms by which clindamycin reduces lesions of acne vulgaris have not been fully elucidated; however, the effect appears to partly result from the antibacterial activity of the drug. Following topical application to the skin of a 1% hydroalcoholic solution of clindamycin as the hydrochloride or the phosphate, the drug inhibits the growth of susceptible organisms (primarily Propionibacterium acnes ) on the surface of the skin and reduces the concentration of free fatty acids in sebum. The reduction in free fatty acids in sebum may be an indirect result of the inhibition of lipase-producing organisms that convert triglycerides into free fatty acids or may be a direct result of interference with lipase production in these organisms. Free fatty acids are comedogenic and are believed to be a possible cause of the inflammatory lesions (e.g., papules, pustules, nodules, cysts) of acne. However, other mechanisms also appear to be involved because clinical improvement of acne vulgaris with topical clindamycin therapy does not necessarily correspond with a reduction in the bacterial flora of the skin or a decrease in the free fatty acid content of sebum. In one study, clindamycin inhibited the growth of P. acnes within open comedones following topical application of a 1% solution of clindamycin as the phosphate in a pyrollidone vehicle (a vehicle that presumably enhances penetration); however, neither erythromycin base nor tetracycline hydrochloride inhibited these organisms within open comedones following topical application of 1% solutions of these drugs in the same vehicle. Topical application of a 1% hydroalcoholic solution of clindamycin as the base or as the phosphate also resulted in inhibition of P. acnes within open comedones.

In an in vitro study, clindamycin hydrochloride inhibited leukocyte chemotaxis. It has been hypothesized that this effect, if it occurs in vivo, could be another mechanism by which clindamycin suppresses the inflammatory lesions of acne vulgaris.

Spectrum

In general, clindamycin is active in vitro and in vivo against most aerobic gram-positive cocci5,6 and several anaerobic and microaerophilic gram-negative and gram-positive organisms.5,6,10 The drug is inactive against Enterobacteriaceae, fungi, and viruses. In vitro, clindamycin concentrations of 0.04-0.4 mcg/mL inhibit most susceptible strains of staphylococci,5,6 streptococci,5,6 pneumococci,5,6 Actinomyces ,6,10 Arachnia propionica ,5 Corynebacterium diphtheriae ,6 and Propionibacterium acnes ;6,13,22 clindamycin concentrations of 0.1-4 mcg/mL inhibit most susceptible strains of Clostridium ,6 Fusobacterium ,6 Moraxella ,14 Mycoplasma ,6 and Neisseria gonorrhoeae 5,6 in vitro.

Clindamycin is active in vitro and in vivo against Gardnerella vaginalis (formerly Haemophilus vaginalis ).100,104,117,122,128 The drug also is active in vitro against Mycoplasma hominis 100,134 and anaerobic organisms including Bacteroides ,100 Prevotella 122,124 and Porphyromonas 122 (both formerly classified as Bacteroides ), Peptostreptococcus ,100,122,124 and Mobiluncus .100,118,122,123

Resistance

Staphylococcal resistance to clindamycin has been induced in vitro and has been shown to be acquired in a stepwise manner. Natural and acquired resistance to clindamycin have been demonstrated in vitro and in vivo in strains of staphylococci, streptococci, pneumococci, and C. diphtheriae.

Complete cross-resistance occurs between clindamycin and lincomycin and partial cross-resistance occurs between clindamycin, lincomycin, and erythromycin. In vitro, bacteria resistant to erythromycin and susceptible to clindamycin or lincomycin may exhibit a dissociated type of resistance to the latter drugs during susceptibility testing if erythromycin is also present. This phenomenon may be the result of competition between erythromycin and clindamycin or lincomycin for the ribosomal binding site.

Pharmacokinetics

In all studies in the Pharmacokinetics section, clindamycin was administered topically, intravaginally, or parenterally as the phosphate ester and orally as the hydrochloride, unless otherwise noted; dosages and concentrations of the drug are expressed in terms of clindamycin.

Absorption

Topical Administration

Clindamycin phosphate is absorbed systemically following topical application of the drug.1 Animal studies indicate that topical application of clindamycin as the hydrochloride results in a more rapid rate of systemic absorption of clindamycin than does topical application of clindamycin as the phosphate. In humans, 0.7 mcg/mL or less of clindamycin has been detected in urine following twice daily application to the skin of a 1% hydroalcoholic solution of clindamycin as the hydrochloride (not commercially available in the US). Following multiple application to the skin of a 1% hydroalcoholic solution of clindamycin as the phosphate, low concentrations of the drug (0-3 ng/mL) have been detected in serum and less than 0.2% of the dose was detected in urine unchanged.

Because topical application of clindamycin as the phosphate appears to result in less systemic absorption of clindamycin than does topical application of clindamycin as the hydrochloride, clindamycin phosphate is the preferred salt for topical therapy. In vivo studies indicate that clindamycin penetrates comedones following topical application. In one study, comedonal concentrations of clindamycin averaged 597 mcg/g of comedonal material following twice daily application to the skin of the commercially available clindamycin phosphate topical solution.

In a comparative study in 78 patients evaluating the pharmacokinetics of a topical solution containing clindamycin 1% and a topical gel containing clindamycin phosphate 1% in fixed combination with benzoyl peroxide 5% (Duac^®), mean plasma clindamycin concentrations reported for both topical preparations were less than 0.5 ng/mL during the 4-week study.178 Benzoyl peroxide is absorbed by the skin where it is converted to benzoic acid; less than 2% of the dose of benzoyl peroxide enters systemic circulation as benzoic acid.178,179

Intravaginal Administration

Clindamycin phosphate is absorbed systemically following intravaginal application of the drug as a vaginal cream or suppositories.100,108,176 The systemic bioavailability of intravaginally administered clindamycin 2% vaginal cream (Cleocin^®) is about 5% and that of the suppositories after three 100 mg daily doses is almost 30%. 100,176 Only low concentrations of the drug are achieved systemically following administration of usual intravaginal doses (e.g., 100 mg of clindamycin) relative to usual oral doses (e.g., 300 mg of clindamycin).100,142,176 Average serum clindamycin concentrations following IV administration of a single dose of the drug (approximately 48 mg of clindamycin) were up to 300-fold greater than those following intravaginal application of clindamycin 50 mg as the cream.108 In addition, the overall systemic bioavailability of clindamycin following intravaginal administration of the suppository is 2- to 20-fold lower than that with usual oral dosages and 40- to 50-fold lower than that with parenteral dosages of the drug.176

Following intravaginal administration of 5 g of the 2% vaginal cream (Cleocin^®; 100 mg of clindamycin) daily for 7 consecutive days in a limited number of healthy women, approximately 5% (range: 0.6-11%) of the administered dose was absorbed systemically.100 Peak serum clindamycin concentrations approximately 10 hours (range: 4-24 hours) after administration averaged 18 ng/mL (range: 4-47 ng/mL) and 25 ng/mL (range: 6-61 ng/mL) on days 1 and 7 of therapy, respectively.100

Following intravaginal administration of a single dose of clindamycin vaginal cream (Clindesse^®) in a limited number of healthy women, peak plasma concentrations averaged 6.6 ng/mL (range: 0.8-39 ng/mL).180

Following intravaginal administration of the suppository (100 mg of clindamycin) once daily for 3 consecutive days in a limited number of healthy women, approximately 30% (range: 6-70%) of the administered dose was absorbed systemically on day 3 of therapy as measured by the area under the concentration-time curve (AUC).176 Peak serum clindamycin concentrations approximately 5 hours (range: 1-10 hours) after intravaginal administration averaged 0.27 mcg/mL (range: 0.03-0.67 mcg/mL) on day 3 of therapy.176

Systemic absorption of intravaginal clindamycin cream (Cleocin^®) was slower and less variable in women with bacterial vaginosis than in healthy women.100 Following intravaginal administration of 5 g of the 2% vaginal cream (100 mg of clindamycin) daily for 7 consecutive days in a limited number of women with bacterial vaginosis, approximately 5% (range: 2-8%) of the administered dose was absorbed systemically.100 Peak serum clindamycin concentrations approximately 14 hours (range: 4-24 hours) after administration averaged 13 ng/mL (range: 6-34 ng/mL) and 16 ng/mL (range: 7-26 ng/mL) on days 1 and 7 of therapy, respectively.100 Little or no systemic accumulation of clindamycin appears to occur following repeated application of clindamycin 2% vaginal cream.100

In a limited number of healthy women who received intravaginal application of a 1% vaginal cream (50 mg of clindamycin; not commercially available in the US) once daily for 7 days, average peak serum clindamycin concentrations at steady state ranged from 20-27 ng/mL; approximately 6% of the dose was absorbed systemically.108 In a limited number of healthy women who received intravaginal application of a 1% vaginal cream (50 mg of clindamycin) twice daily for 7 days, average peak serum clindamycin concentrations were 3-5 times higher than those in the group receiving the same dose once daily, and an average of 12-14% of the dose was absorbed systemically.108

Distribution and Elimination

The distribution and elimination characteristics of clindamycin following intravaginal application of the drug have not been fully characterized.150 Following intravaginal application of 2% clindamycin cream (Cleocin^®), the systemic half-life of the drug appears to be about 1.5-2.6 hours.100 Following intravaginal administration of clindamycin suppositories, the apparent elimination half-life averaged about 11 hours (range: 4-35 hours).176 Elimination of clindamycin suppositories is considered to be limited by absorption rate.176

Chemistry and Stability

Chemistry

Clindamycin is a semisynthetic derivative of lincomycin,5,6,7,100 an antibiotic obtained from cultures of Streptomyces lincolnensis. 5 Clindamycin differs structurally from lincomycin in the substitution of a chlorine atom for the 7-hydroxyl group and the inversion of the involved 7-carbon.5,7,100

Clindamycin is commercially available for topical or vaginal use as the phosphate ester; potency of clindamycin phosphate is expressed in terms of clindamycin.100 Clindamycin phosphate occurs as a white to off-white, hygroscopic, crystalline powder that is odorless or practically odorless and has a bitter taste. The drug has a solubility of approximately 400 mg/mL in water at 25°C and is slightly soluble in dehydrated alcohol.

For the topical treatment of acne vulgaris, clindamycin phosphate 1% is commercially available as a gel containing allantoin, carbomer 934P, methylparaben, polyethylene glycol 400, propylene glycol, sodium hydroxide, and purified water; a lotion containing cetearyl alcohol 2.5%, methylparaben 0.3%, glyceryl stearate SE (with potassium monostearate), glycerin, sodium lauroyl sarcosinate, stearic acid, isostearyl alcohol, and water; and a solution in a vehicle containing isopropyl alcohol 50%, propylene glycol, and water. Clindamycin phosphate topical solutions have a pH of 4-7.

For the topical treatment of acne vulgaris, clindamycin phosphate (clindamycin 1%) in fixed combination with benzoyl peroxide 5% (Duac^®) is available as a gel containing carbomer 940, dimethicone, disodium lauryl sulfosuccinate, edetate disodium, glycerin, silicon dioxide, methylparaben, poloxamer, purified water, and sodium hydroxide.178 Clindamycin phosphate (clindamycin 1%) also is available as powder that is reconstituted and admixed with benzoyl peroxide 5% gel at the time of dispensing (BenzaClin^®); the benzoyl peroxide gel also contains carbomer, sodium hydroxide, docusate sodium, and purified water.179

For vaginal use, clindamycin phosphate is commercially available as a cream (Cleocin^®) containing benzyl alcohol, cetostearyl alcohol, cetyl palmitate, mineral oil, polysorbate 60, propylene glycol, purified water, sorbitan monostearate, and stearic acid.100 Each gram of Cleocin^® vaginal cream contains 20 mg of clindamycin.100,150 The pH of the vaginal cream is 3-6.100

Clindamycin phosphate also is commercially available as a vaginal cream (Clindesse^®) containing edetate disodium, parabens, microcrystalline wax, and other ingredients.180 Each gram of Clindesse^® vaginal cream contains 20 mg of clindamycin.180

Clindamycin phosphate also is commercially available for vaginal administration as a vaginal suppository.176 Each 2.5 g vaginal suppository contains 100 mg of clindamycin (as the phosphate) in a base containing a mixture of glycerides of saturated fatty acids.

Stability

Commercially available clindamycin phosphate 1% topical gel, lotion, and solution should be stored in tight containers at 20-25°C; freezing should be avoided.1

The commercially available gel containing clindamycin phosphate (clindamycin 1%) in fixed combination with benzoyl peroxide 5% (Duac^®) should be refrigerated at 2-8°C until dispensed.178 Once dispensed, the gel may be stored at a room temperature up to 25°C for up to 60 days.178 The gel should not be frozen.178

The commercially available clindamycin phosphate powder and benzoyl peroxide gel (BenzaClin^®) should be stored at a room temperature up to 25°C.179 After the clindamycin phosphate powder is reconstituted and admixed with the benzoyl peroxide gel at the time of dispensing, the gel should be stored at room temperature and is stable for 3 months.179

Commercially available clindamycin phosphate vaginal cream (Cleocin^®) should be stored in a tight container at 20-25°C; freezing should be avoided.100 The vaginal suppositories176 and clindamycin phosphate vaginal cream (Clindesse^®)180 should be stored at a controlled room temperature of 25°C, but may be exposed to temperatures ranging from 15-30°C; exposure to temperatures exceeding 30°C or high humidity should be avoided. When stored as recommended, the commercially available vaginal cream is stable for 18 months following the date of manufacture.150

Additional Information

The American Society of Health-System Pharmacists, Inc. represents that the information provided in the accompanying monograph was formulated with a reasonable standard of care, and in conformity with professional standards in the field. Readers are advised that decisions regarding use of drugs are complex medical decisions requiring the independent, informed decision of an appropriate health care professional, and that the information contained in the monograph is provided for informational purposes only. The manufacturer's labeling should be consulted for more detailed information. The American Society of Health-System Pharmacists, Inc. does not endorse or recommend the use of any drug. The information contained in the monograph is not a substitute for medical care.

Only references cited for selected revisions after 1984 are available electronically.

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