Sulfamylon® for 5% Topical Solution

• Bacteriostatic action against many organisms reduces risk of infection
• Activity not altered by changes in the acidity of the environment
• Suitable for topical administration

Indicated for use as an adjunctive topical antimicrobial agent to control bacterial infection when used under moist dressings over meshed autografts on excised burn wounds.

Sulfamylon® 5% Solution is contraindicated for patients who are hypersensitive to mafenide acetate. It is not known whether there is cross-sensitivity to other sulfonamides.

Fatal hymolytic anemia with disseminated intravascular coagulation, presumably related to a glucose-6-phosphate dehydrogenase deficiency, has been reported following Sulfamylon® therapy with mafenide acetate.

Mafenide acetate and its metabolite, p-carboxybenzenesulfonamide, inhibit carbonic anhydrase, which may result in metabolic acidosis, usually compensated by hyperventilation. In the presence of impaired renal function, high blood levels of mafenide acetate and its metabolite may exaggerate the carbonic anhydrase inhibition. Therefore, close monitoring of acid-base balance is necessary, particularly in patients with extensive second-degree or partial-thickness burns and in those with pulmonary or renal dysfunction. Some burn patients treated with mafenide acetate have also been reported to manifest an unexplained syndrome of masked hyperventilation with resulting respiratory alkalosis (slightly alkaline blood pH, low arterial pCO2, and decreased total CO2); change in arterial pO2 is variable. The etiology and significance of these findings are unknown.

Mafenide acetate should be used with caution in burn patients with acute renal failure.

Fungal colonization may occur concomitantly with reduction of bacterial growth in the burn wound. However, systemic fungal infection through the infected burn wound is rare.

Carcinogenesis, Mutagenesis, Impairment of Fertility: No long-term animal studies have been performed to evaluate the carcinogenic potential of mafenide acetate; however, the drug did not induce mutations in the L5178Y mouse lymphoma cells at the TK locus.

Animal studies have not been performed to evaluate the potential effects of mafenide acetate on fertility.

Pregnancy: Teratogenic Effects. Pregnancy Category C: A teratology study performed in rats using oral doses of up to 600 mg/kg/day revealed no evidence of harm to the fetus due to mafenide acetate. There are no adequate data regarding the potential reproductive toxicity of mafenide acetate in a non-rodent species, nor are there adequate and well controlled studies in pregnant women. Mafenide acetate should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Nursing mothers: It is not known whether mafenide acetate is excreted in human milk. Because many drugs are excreted in human milk and because of the potential for serious adverse reaction in nursing infants from mafenide acetate, 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.

In the clinical setting of severe burns, it is often difficult to distinguish between an adverse reaction to mafenide acetate and burn sequelae. In a clinical study of pediatric patients with acute burns requiring autografts who received Sulfamylon® 5% Solution in addition to double antibiotic solution (DAB) wound therapy (neomycin sulfate 40 mg and polymyxin B 200,000 units/liter), the incidence of rash (4.6%) and itching (2.8%) in the group which received Sulfamylon® 5% Solution was not different from that experienced with (DAB) dressings alone (5.7% and 1.3%, respectively).

From other clinical settings, a single case of bone marrow depression and a single case of an acute attack of porphyria have been reported following therapy with mafenide acetate. Fatal hemolytic anemia with disseminated intravascular coagulation, presumably related to a glucose-6-phosphate dehydrogenase deficiency, has been reported following therapy with mafenide acetate. The following adverse reactions have been reported with topical mafenide acetate therapy:

Dermatologic and Allergic: Pain or burning sensation, rash and pruritus (often localized to the area covered by the wound dressing), erythema, skin maceration from prolonged wet dressings, facial edema, swelling, hives, blisters, eosinophilia.

Respiratory or Metabolic: Tachypnea, hyperventilation, decrease in pCO2, metabolic acidosis, increase in serum chloride.

Overdosage: Single oral doses of 2000 mg/kg of mafenide acetate as a 5% solution did not cause mortality or clinical symptoms of toxicity in rats.

The reconstituted Sulfamylon® 5% Solution may be held up to 28 days after preparation if stored in unopened containers. Once a container is opened, any unused portion should be discarded after 48 hours.

Store the reconstituted solution at 20º to 25ºC (68º to 77ºF). Limited storage periods at 15º to 30ºC (59º to 86º) are acceptable.