• PO, IV: Treatment of the following anaerobic infections:
  • Intra-abdominal infections (may be used with a cephalosporin),
  • Gynecologic infections,
  • Skin and skin structure infections,
  • Lower respiratory tract infections,
  • Bone and joint infections,
  • CNS infections,
  • Septicemia,
  • Endocarditis.
• IV: Perioperative prophylactic agent in colorectal surgery.
• PO: Treatment of the following infections:
  • Amebic dysentery, amebic liver abscess, and trichomoniasis
  • Peptic ulcer disease caused by Helicobacter pylori.
• Topical: Acne rosacea.
• Vag: Bacterial vaginosis.

Unlabeled Uses:

• Giardiasis.
• Anti-infective associated Clostridioides difficile-associated diarrhea (CDAD).

Contraindicated in:

• Hypersensitivity
• Hypersensitivity to parabens (topical only)
• Cockayne syndrome (↑ risk of hepatotoxicity and death)
• OB: First trimester of pregnancy.

Use Cautiously in:

• History of blood dyscrasias
• History of seizures or neurologic problems
• Severe hepatic impairment (dose ↓ suggested)
• Patients receiving corticosteroids or predisposed to edema (injection contains 28 mEq sodium/g metronidazole)
• OB: Although safety has not been established, has been used to treat trichomoniasis in 2nd- and 3rd-trimester pregnancy—but not as single-dose regimen
• Lactation: If needed, use single dose and interrupt nursing for 24 hr thereafter.

Derm: rash, STEVENS-JOHNSON SYNDROME (SJS), urticaria.
topical only: burning, mild dryness, skin irritation, transient redness.

EENT: optic neuropathy, tearing (topical only).

GI: abdominal pain, anorexia, nausea, diarrhea, dry mouth, furry tongue, glossitis, unpleasant taste, vomiting.

Hemat: leukopenia.

Local: phlebitis at IV site.

Neuro: dizziness, headache, aseptic meningitis (IV), encephalopathy (IV), peripheral neuropathy, psychosis, SEIZURES.
Misc: superinfection.

Drug-Drug:

• Cimetidine may ↑ levels and risk of toxicity.
• Phenobarbital and rifampin may ↓ levels and effectiveness.
• May ↑ levels and the risk of toxicity of phenytoin, lithium, and warfarin.
• Disulfiram-like reaction may occur with alcohol ingestion.
• May cause acute psychosis and confusion with disulfiram.
• ↑ risk of leukopenia with fluorouracil or azathioprine.
• Use with QT interval prolonging medications may ↑ risk of QT interval prolongation.

(Generic available)

• Tablets: 250 mg; 500 mg;
• Capsules: 375 mg; 500 mg;
• Premixed infusion: 500 mg/100 mL;
• Topical cream: 0.75%; 1%;
• Topical gel: 0.75%; 1%;
• Topical lotion: 0.75%;
• Vaginal cream: 10% (500 mg/applicatorful);
• Vaginal gel: 0.75% (37.5 mg/5 g applicatorful); 1.3% (65 mg/5 g applicatorful);
• In combination with: bismuth subcitrate potassium and tetracycline (Pylera). See Appendix [not included in this PDA edition].

• PO (Adults): Anaerobic infections: 7.5 mg/kg every 6 hr (not to exceed 4 g/day). Trichomoniasis: 250 mg every 8 hr for 7 days or single 2-g dose or 1 g twice daily for 1 day. Amebiasis: 500–750 mg every 8 hr for 5–10 days. H. pylori: 250 mg 4 times daily or 500 mg twice daily for 1–2 wk (with other agents). Antibiotic associated Clostridioides difficile-associated diarrhea (CDAD): 250–500 mg 3–4 times/day for 10–14 days.
• PO (Infants and Children): Anaerobic infections: 30 mg/kg/day divided every 6 hr, maximum dose: 4 g/day Trichomoniasis: 15–30 mg/kg/day divided every 8 hr for 7–10 days. Amebiasis: 35–50 mg/kg/day divided every 8 hr for 5–10 days (not to exceed 750 mg/dose). Clostridioides difficile-associated diarrhea (CDAD): 30 mg/kg/day divided every 6 hr for 7–10 days. H. pylori: 15–20 mg/kg/day divided twice daily for 4 wk.
• IV, PO (Neonates 0–4 wk, <1200 g): 7.5 mg/kg every 48 hr. Postnatal age <7 days, 1200–2000 g: 7.5 mg/kg/day every 24 hr. Postnatal age <7 days, >2000 g: 15 mg/kg/day divided every 12 hr. Postnatal age >7 days, 1200–2000 g: 15 mg/kg/day divided every 12 hr. Postnatal age >7 days, >2000 g: 30 mg/kg/day divided every 12 hr.
• IV (Adults): Anaerobic infections: Initial dose 15 mg/kg, then 7.5 mg/kg every 6–8 hr or 500 mg every 6–8 hr (not to exceed 4 g/day). Perioperative prophylaxis: Initial dose 15 mg/kg 1 hr before surgery, then 7.5 mg/kg 6 and 12 hr later. Amebiasis: 500–750 mg every 8 hr for 5–10 days.
• IV (Children): Anaerobic infections: 30 mg/kg/day divided every 6 hr, maximum dose: 4 g/day.
• Topical (Adults): Acne rosacea: Apply thin film to affected area bid.
• Vag (Adults): 0.75% vaginal gel: One applicatorful (37.5 mg) of 0.75% gel 1–2 times daily for 5 days; Nuvessa: One applicatorful (65 mg) of 1.3% gel as a single dose at bedtime; Vandazole: One applicatorful (37.5 mg) of 0.75% gel once daily for 5 days.
• Vag (Children ≥12 yr): Nuvessa: One applicatorful (65 mg) of 1.3% gel as a single dose at bedtime.
• Vag (Children Post-menarchal): Vandazole: One applicatorful (37.5 mg) of 0.75% gel once daily for 5 days.

Flagyl, MetroCream, MetroGel, MetroLotion, Noritate, Nuvessa, Vandazole

• Disrupts DNA and protein synthesis in susceptible organisms.

• Bactericidal, trichomonacidal, or amebicidal action.

Spectrum:

• Most notable for activity against anaerobic bacteria, including:
  • Bacteroides spp.,
  • Clostridioides difficile.
  • Gardnerella vaginalis
  • Mobiluncus spp.
  • Peptostreptococcus spp.
• In addition, is active against:
  • Trichomonas vaginalis,
  • Entamoeba histolytica,
  • Giardia lamblia,
  • H. pylori,

Therapeutic Classification: anti-infectives, antiprotozoals, antiulcer agents

Absorption: 80% absorbed after oral administration. Minimal absorption after topical or vaginal application.

Distribution: Widely distributed into most tissues and fluids, including CSF.

Metabolism/Excretion: Partially metabolized by the liver (30–60%), partially excreted unchanged in the urine, 6–15% eliminated in the feces.

Half-life: Neonates: 25–75 hr; Children and adults: 6–12 hr.

Nidagel

(PO, IV = blood levels; topical = improvement in rosacea)

• Instruct patient to take medication as directed with evenly spaced times between doses, even if feeling better. Do not skip doses or double up on missed doses. Take missed doses as soon as remembered if not almost time for next dose.
• Advise patients treated for trichomoniasis that sexual partners may be asymptomatic sources of reinfection and should be treated concurrently. Patient should also refrain from intercourse or use a condom to prevent reinfection.
• Caution patient to avoid intake of alcoholic beverages or preparations containing alcohol during and for at least 3 days after treatment with metronidazole, including vaginal gel. May cause a disulfiram-like reaction (flushing, nausea, vomiting, headache, abdominal cramps).
• May cause dizziness or light-headedness. Caution patient to avoid driving or other activities requiring alertness until response to medication is known.
• Instruct patient to notify health care professional promptly if rash occurs.
• Inform patient that medication may cause an unpleasant metallic taste.
• Advise patient to notify health care professional of all Rx or OTC medications, vitamins, or herbal products being taken and to consult with health care professional before taking other medications.
• Advise patient that frequent mouth rinses, good oral hygiene, and sugarless gum or candy may minimize dry mouth. Notify health care professional if dry mouth persists for more than 2 wk.
• Inform patient that medication may cause urine to turn dark.
• Advise patient to consult health care professional if no improvement in a few days or if signs and symptoms of superinfection (black, furry overgrowth on tongue; vaginal itching or discharge; loose or foul-smelling stools) develop.
• Advise females of reproductive potential to inform health care professional if pregnancy is planned or suspected and to avoid breastfeeding during therapy.
• Vag: Instruct patient in correct technique for intravaginal instillation. Advise patient to avoid intercourse during treatment with vaginal gel.
• Topical: Instruct patient on correct technique for application of topical gel. Cosmetics may be used after application of gel.

me-troe-NI-da-zole