There is a potential cross sensitivity between silver sulfadiazine and other sulfonamides. If allergic reactions attributable to treatment with silver sulfadiazine occur, continuation of therapy must be weighed against the potential hazards of the particular allergic reaction.
Fungal proliferation in and below the eschar may occur. However, the incidence of clinically reported fungal superinfection is low.
The use of Silver Sulfadiazine Cream in some cases of glucose-6-phosphate dehydrogenase-deficient individuals may be hazardous, as hemolysis may occur.
If hepatic and renal functions become impaired and elimination of the drug decreases, accumulation may occur and discontinuation of Silver Sulfadiazine Cream should be weighed against the therapeutic benefit being achieved.
In considering the use of topical proteolytic enzymes in conjunction with Silver Sulfadiazine Cream, the possibility should be noted that silver may inactivate such enzymes.
In the treatment of burn wounds involving extensive areas of the body, the serum sulfa concentrations may approach adult therapeutic levels (8 to 12 mg %). Therefore, in these patients it would be advisable to monitor serum sulfa concentrations. Renal function should be carefully monitored and the urine should be checked for sulfa crystals.
Absorption of the propylene glycol vehicle has been reported to affect serum osmolality, which may affect the interpretation of laboratory tests.
Carcinogenesis, Mutagenesis, Impairment of Fertility
Long-term dermal toxicity studies of 24 months duration in rats and 18 months in mice with concentrations of silver sulfadiazine three to ten times the concentration in Silver Sulfadiazine Cream revealed no evidence of carcinogenicity.
Pregnancy category B. A reproductive study has been performed in rabbits at doses up to three to ten times the concentration of silver sulfadiazine in Silver Sulfadiazine Cream and has revealed no evidence of harm to the fetus due to silver sulfadiazine. There are, however, no adequate and well controlled studies in pregnant women. Because animal reproduction studies are not always predictive of human response, this drug should be used during pregnancy only if clearly justified, especially in pregnant women approaching or at term.
It is not known whether Silver Sulfadiazine Cream is excreted in human milk. However, sulfonamides are known to be excreted in human milk and all sulfonamides derivatives are known to increase the possibility of kernicterus. Because of the potential for serious adverse reactions in nursing infants from sulfonamides, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother.
Safety and effectiveness in children have not been established.
Several cases of transient leucopenia have been reported in patients receiving silver sulfadiazine therapy. Leucopenia associated with silver sulfadiazine administration is primarily characterized by decreased neutrophil count. Maximal white blood cell depression occurs within two to four days of initiation of therapy. Rebound to normal leukocyte levels follows onset within two to three days. Recovery is not influenced by continuation of silver sulfadiazine therapy. The incidence of leucopenia in various reports averages about 20%. A higher incidence has been seen in patients treated concurrently with cimetidine.
Other infrequently occurring events include skin necrosis, erythema multiforme, skin discoloration, burning sensation, rashes, and interstitial nephritis. Reduction in bacterial growth after application of topical antibacterial agents has been reported to permit spontaneous healing of deep partial-thickness burns by preventing conversion of the partial thickness to full thickness by sepsis. However, reduction in bacterial colonization has caused delayed separation, in some cases necessitating escharotomy in order to prevent contracture.
Absorption of silver sulfadiazine varies depending upon the percent of body surface area and the extent of the tissue damage. Although few have been reported, it is possible that any adverse reaction associated with sulfonamides may occur. Some of the reactions which have been associated with sulfonamides are as follows: blood dyscrasias, including agranulocytosis, aplastic anemia, thrombocytopenia, leucopenia, hemolytic anemia; dermatologic and allergic reactions, Stevens-Johnson syndrome and exfoliative dermatitis; gastrointestinal reactions; hepatitis and hepatocellular necrosis; CNS reactions; and toxic nephrosis.