Mafenide acetate

CLINICAL PHARMACOLOGY

INDICATIONS & USAGE

Mafenide Acetate,USP For 5% Topical Solution is 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.

MAFENIDE ACETATE CONTRAINDICATIONS

WARNINGS

Fatal hemolytic anemia with disseminated intravascular coagulation, presumably related to a glucose-6-phosphate dehydrogenase deficiency, has been reported following therapy with Mafenide Acetate.

PRECAUTIONS

General:

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.

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 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 reactions 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.

Pediatric Use:

The safety and effectiveness of Mafenide Acetate,USP For 5% Topical Solution have been established in the age groups 3 months to 16 years.

Geriatric Use:

No studies have been conducted to specifically examine the effects of Mafenide Acetate on burn wounds in geriatric patients.

MAFENIDE ACETATE ADVERSE REACTIONS

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 Mafenide Acetate,USP for  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 Mafenide Acetate USP For 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:

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.

DOSAGE & ADMINISTRATION

Wound dressings may be left undisturbed, except for the irrigations, for up to five days. Additional soaks may be initiated until graft take is complete. Maceration of skin may result from wet dressings applied for intervals as short as 24 hours. Treatment is usually continued until autograft vascularization occurs and healing is progressing (typically occurring in about 5 days). Safety and effectiveness have not been established for longer than 5 days for an individual grafting procedure. 

If allergic manifestations occur during treatment with Mafenide Acetate ,USP for 5% solution, discontinuation of treatment should be considered. If acidosis occurs and becomes difficult to control, particularly in patients with pulmonary dysfunction, discontinuing the soaks with the mafenide acetate solution for 24 to 48 hours may aid in restoring acid-base balance (see PRECAUTIONS section). Dressing changes and monitoring the site for bacterial growth during this interruption should be adjusted accordingly.

HOW SUPPLIED

Mafenide Acetate , USP for 5% Topical Solution is available in packets containing 50 g of sterile Mafenide Acetate to be prepared using 1000 mL Sterile Water for Irrigation, USP or 0.9% Sodium Chloride Irrigation, USP. (See DOSAGE AND ADMINISTRATION: MAFENIDE ACETATE USP for 5% Topical Solution: Directions for Preparation of the Solution.) The packets are supplied as follows:

Carton of five 50 g packets (NDC # 49884-902-78).

The solution may be held for up to 28 days if stored in unopened containers.

ONCE A CONTAINER IS OPENED, ANY UNUSED SOLUTION MUST BE DISCARDED WITHIN 48 HOURS.

PACKAGE LABEL.PRINCIPAL DISPLAY PANEL