Silver sulfadiazine is a synthetic anti-infective agent produced by the reaction of silver nitrate with sulfadiazine.
Silver sulfadiazine is used as an adjunct in the prevention and treatment of infection in second- and third-degree burns after resuscitative measures (including control of shock and pain, and correction of electrolyte imbalance) have been instituted. Because infection may extend tissue destruction beyond the burned area and may destroy epithelial islands that could initiate healing, control of bacterial growth may prevent the conversion of deep, partial-thickness wounds to full thickness. Concomitant administration of appropriate systemic anti-infective agents may be necessary if infection is present or suspected.
Although silver sulfadiazine appears to be as effective as silver nitrate or mafenide, controlled studies comparing the effectiveness of silver sulfadiazine and other standard antibacterial burn treatments have not been published. Mafenide appears to penetrate the burn eschar better than does silver sulfadiazine and, therefore, may be more effective in minimizing the growth of bacteria. However, because of the softening action of silver sulfadiazine cream, removal of the eschar and preparation of the wound for grafting is apparently easier than after treatment with mafenide preparations. Unlike mafenide, silver sulfadiazine is not a carbonic anhydrase inhibitor and, therefore, does not alter acid-base balance. Unlike silver nitrate solutions, silver sulfadiazine cream does not alter electrolyte balance and does not stain tissues or dressings.
Silver sulfadiazine, as a 1% cream, is applied topically to cleansed, debrided, burned areas once or twice daily using a sterile-gloved hand. The cream should be applied to a thickness of approximately 16 mm (one-sixteenth inch); the burned area should be covered with cream at all times. If necessary, the cream should be reapplied to any areas from which it has been removed by patient activity. If possible, the patient should be bathed daily to aid in debridement. Dressings are usually not required but may be used. Silver sulfadiazine cream should be applied to the burn wound as long as there is a possibility of infection, unless a clinically important adverse reaction occurs. Therapy is usually continued until healing is progressing well or until the site is ready for grafting.
Pain, burning, or itching have occasionally been reported following application of silver sulfadiazine cream; however, the incidence and severity of local irritation is much less than that following application of mafenide salts. Rashes may also occur, but are generally localized and respond to treatment with antihistamines. Necrosis of the skin, erythema multiforme, and transient skin discoloration also have been reported following application of silver sulfadiazine cream.
When silver sulfadiazine is applied to extensive areas of the body surface, sulfadiazine may be absorbed systemically and may produce adverse reactions characteristic of the sulfonamides, including hemolytic anemia (in patients with glucose-6-phosphate dehydrogenase deficiency), agranulocytosis, aplastic anemia, thrombocytopenia, leukopenia, dermatologic and hypersensitivity reactions (e.g., Stevens-Johnson syndrome, exfoliative dermatitis), adverse GI effects, hepatitis and hepatocellular necrosis, adverse nervous system effects, and toxic nephrosis. (See Cautions in the Sulfonamides General Statement 8:12.20.) Reversible leukopenia may occur in the first 4 days of silver sulfadiazine therapy and is manifested principally by a decreased neutrophil count; the leukocyte count returns to normal within 2-3 days after the onset of leukopenia. Interstitial nephritis has been reported rarely.
Precautions and Contraindications
Sulfadiazine may accumulate in patients with impaired hepatic or renal function, and discontinuance of silver sulfadiazine should be considered if therapeutic benefits to the patient do not outweigh the possible risks. In patients with extensive burns, serum sulfonamide concentrations and renal function should be monitored, and urine should be examined for sulfonamide crystals. Absorption of propylene glycol (contained in silver sulfadiazine cream) can affect serum osmolality which may interfere with some laboratory test results.
The inhibition of proteolytic enzyme-producing bacteria by silver sulfadiazine may result in delayed eschar separation, and escharectomy may be required occasionally. Fungal superinfection may occur.
Silver sulfadiazine cream should be used with caution in individuals with known hypersensitivity to silver sulfadiazine or methylparaben, and discontinuance of the drug should be considered if an allergic reaction develops during therapy. The possibility of cross-hypersensitivity with other sulfonamides should be kept in mind.
Because sulfonamide therapy has produced kernicterus in neonates, silver sulfadiazine cream is contraindicated in premature neonates or neonates younger than 2 months of age.
No evidence of carcinogenesis was seen in mice receiving topical silver sulfadiazine dosages 3-10 times the usual human dosage for 18 months.
Reproduction studies in rabbits using silver sulfadiazine 3-10 times the usual human dosage have not revealed evidence of harm to the fetus. There are no adequate and controlled studies to date using silver sulfadiazine in pregnant women, and the drug should be used during pregnancy only when clearly needed. The drug is not recommended for use in pregnant women unless the burned area covers more than 20% of the body surface or the therapeutic benefits to the patient outweigh the possible risks to the fetus. Because sulfonamide therapy has produced kernicterus in neonates, silver sulfadiazine cream is contraindicated in pregnant women approaching or at term.
It is not known whether silver sulfadiazine is distributed into human milk. Because sulfonamides are distributed into milk and sulfonamides may cause kernicterus in infants younger than 2 months of age, silver sulfadiazine should be used with caution in nursing women.
The mechanism of action of silver sulfadiazine appears to be distinct from that of sulfadiazine and silver nitrate. Silver sulfadiazine acts upon the cell membrane and cell wall. Unlike sulfadiazine and other sulfonamides, the antibacterial action of the silver salt of sulfadiazine does not appear to depend on inhibition of bacterial folic acid synthesis; silver sulfadiazine's activity is not competitively inhibited by aminobenzoic acid ( p -aminobenzoic acid). Both silver sulfadiazine and silver nitrate bind to DNA in vitro, but, unlike silver nitrate, binding by silver sulfadiazine to DNA does not appear to account for its in vivo activity.
As a topical anti-infective agent, silver sulfadiazine has a wide spectrum of activity. The drug is bactericidal against species of both gram-positive and gram-negative organisms, but resistance has been reported occasionally. In vitro, silver sulfadiazine concentrations of 10-50 mcg/mL inhibit most species of Klebsiella, Proteus, Pseudomonas , and Staphylococcus. Silver sulfadiazine also inhibits Escherichia coli, Corynebacterium diphtheriae, and species of Acinetobacter, Citrobacter, Enterobacter, Providencia, Serratia, and streptococci in vitro. Candida albicans may be inhibited by silver sulfadiazine concentrations of 50-100 mcg/mL, and Herpesvirus hominis may be inhibited by 10 mcg/mL. In higher concentrations, the drug inhibits Clostridium perfringens.
Silver sulfadiazine itself does not appear to be absorbed. When in contact with body tissues and fluids, silver sulfadiazine slowly reacts with sodium chloride, sulfhydryl groups, and protein, resulting in the release of sulfadiazine. Sulfadiazine may be systemically absorbed from the site of application, particularly when silver sulfadiazine is applied to second-degree burns. When the drug is applied to extensive burns, serum sulfadiazine concentrations of up to 12 mg/dL have been reported. In one study, patients who were treated with 5-10 g of silver sulfadiazine daily applied as a 1% cream were found to have blood sulfadiazine concentrations of 1-2 mg/dL; 100-200 mg of sulfadiazine was excreted in urine within 24 hours following application of the cream. When 5-15 g/kg of a cream containing 1% silver sulfadiazine was applied daily for 100 days to experimentally abraded areas on rabbits, an unidentified silver compound was deposited in renal tissue; however, concurrent impairment of renal function was not noted.
Silver sulfadiazine is a synthetic anti-infective agent produced by the reaction of silver nitrate with sulfadiazine. Silver sulfadiazine occurs as a white, fluffy powder and is practically insoluble in water. The commercially available cream contains silver sulfadiazine in micronized form.
Silver sulfadiazine cream should be stored at 15-30°C.
Silver sulfadiazine reacts with most heavy metals; this reaction may result in release of free silver and darkening of the cream. If this occurs, the cream should be discarded. When silver sulfadiazine is used in conjunction with topical proteolytic enzymes, the possibility that silver may inactivate the proteolytic enzymes should be considered; however, the manufacturer of sutilains (no longer commercially available in the US) has stated that this did not occur with its product.
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.
Excipients in commercially available drug preparations may have clinically important effects in some individuals; consult specific product labeling for details.
Please refer to the ASHP Drug Shortages Resource Center for information on shortages of one or more of these preparations.
Routes | Dosage Forms | Strengths | Brand Names | Manufacturer |
|---|---|---|---|---|
Topical | Cream | 1%* | Silvadene® | Monarch |
Silver Sulfadiazine Topical Cream | ||||
SSD® | Par | |||
SSD AF® | Par | |||
Thermazene® | Major |
* available from one or more manufacturer, distributor, and/or repackager by generic (nonproprietary) name