Mafenide

Dosage Forms

Excipient information presented when available (limited, particularly for generics); consult specific product labeling.

Cream, External, as acetate [strength expressed as base]:

Sulfamylon: 85 mg/g (56.7 g, 113.4 g, 453.6 g) [contains methylparaben, propylparaben, sodium metabisulfite]

Packet, External, as acetate:

Sulfamylon: 50 g (1 ea, 5 ea)

Generic: 50 g (1 ea, 5 ea)

Pharmacology

Mechanism of Action

As a sulfonamide, mafenide interferes with bacterial folic acid synthesis through competitive inhibition of para-aminobenzoic acid. Spectrum of activity encompasses both gram positive and negative organisms, including Pseudomonas and some anaerobes.

Pharmacokinetics/Pharmacodynamics

Absorption

Diffuses through devascularized areas and is rapidly absorbed from burned surface

Metabolism

To para-carboxybenzene sulfonamide; mafenide and metabolite are carbonic anhydrase inhibitors

Excretion

Urine (as metabolites)

Time to Peak

Serum: Cream 11%: 2 to 4 hours; Burn tissue: Cream 11%: 2 hours, Solution 5%: 4 hours

Use: Labeled Indications

Burn treatment: For adjunctive therapy of patients with second- and third-degree burns (cream); for use as an adjunctive topical antimicrobial agent to control bacterial infection when used under moist dressings over meshed autografts on excised burn wounds (powder for solution)

Contraindications

Hypersensitivity to mafenide or any component of the formulation

Dosage and Administration

Dosing: Adult

Burn treatment: Topical:

Cream: Apply once or twice daily with a sterile-gloved hand; apply to a thickness of approximately ¹/₁₆ inch (thicker application is not recommended). The burned area should be covered with cream at all times. Continue treatment until healing is progressing well or the burn site is ready for grafting.

Powder for solution: Wet an 8-ply burn dressing with solution and cover graft area. Keep dressing wet using syringe or irrigation tubing every 4 hours (or as necessary) or by moistening dressing every 6 to 8 hours (or as necessary). Continue treatment until autograft vascularization occurs and healing is progressing; may leave dressings in place for ≤5 days.

Dosing: Geriatric

Refer to adult dosing.

Dosing: Pediatric

Burns: Topical:

Cream: Infants, Children, and Adolescents: Apply once or twice daily with a sterile-gloved hand; apply to a thickness of approximately ¹/₁₆ inch; the burned area should be covered with cream at all times.

Solution (5%): Infants ≥3 months, Children, and Adolescents: Cover graft area with 1 layer of fine mesh gauze. Wet an 8-ply burn dressing with mafenide solution and cover graft area. Keep dressing wet using syringe or irrigation tubing every 4 hours (or as necessary), or by moistening dressing every 6 to 8 hours (or as necessary). Irrigation dressing should be secured with bolster dressing and wrapped as appropriate. May leave dressings in place for up to 5 days.

Dosing: Adjustment for Toxicity

Acidosis: When acidosis becomes difficult to control, discontinuing treatment for 24 to 48 hours may aid in restoring acid-base balance

Reconstitution

Powder for solution: To prepare a 5% topical solution, add mafenide 50 g to 1000 mL of NS for irrigation or sterile water for irrigation. Mix until dissolved.

Administration

Topical:

Cream: For external use only. Keep burn area covered with cream at all times. Dressings are typically not required however if necessary only a thin layer of dressings should be used. Apply to clean debrided area with a sterile gloved hand. Apply to a thickness of approximately ¹/₁₆ inch (thicker application is not recommended). Do not discontinue therapy if there is a possibility of infection. If possible, patient should bathe daily to aid debridement (eg, whirlpool bath, shower, or bathed in bed).

Powder for solution: For external use only. Cover graft area with 1 layer of fine mesh gauze. Wet an 8-ply burn dressing with solution until leaking is noticeable and cover graft area. Keep dressing wet using syringe or irrigation tubing or by moistening dressing. Irrigation tubing should be placed over burn dressing in contact with the wound; use an additional 8-ply dressing to cover. Irrigation dressing should be secured with bolster dressing and wrapped as appropriate.

Storage

Cream: Avoid exposure to excessive heat (>40°C [>104°F]).

Powder for solution: Prior to reconstitution, store powder at 15°C to 30˚C (59°F to 86˚F). Store prepared solution at 20°C to 25˚C (68°F to 77˚F); excursions permitted between 15°C and 30°C (59°F and 86°F). May store at 15°C to 30˚C (59°F to 86˚F) for limited periods. Solution may be stored in unopened containers for up to 28 days; once container is open, discard unused portion within 48 hours.

Drug Interactions

BCG (Intravesical): Antibiotics may diminish the therapeutic effect of BCG (Intravesical). Avoid combination

BCG Vaccine (Immunization): Antibiotics may diminish the therapeutic effect of BCG Vaccine (Immunization). Monitor therapy

Dapsone (Topical): May enhance the adverse/toxic effect of Methemoglobinemia Associated Agents. Monitor therapy

Local Anesthetics: Methemoglobinemia Associated Agents may enhance the adverse/toxic effect of Local Anesthetics. Specifically, the risk for methemoglobinemia may be increased. Monitor therapy

Nitric Oxide: May enhance the adverse/toxic effect of Methemoglobinemia Associated Agents. Combinations of these agents may increase the likelihood of significant methemoglobinemia. Monitor therapy

Prilocaine: Methemoglobinemia Associated Agents may enhance the adverse/toxic effect of Prilocaine. Combinations of these agents may increase the likelihood of significant methemoglobinemia. Management: Monitor patients for signs of methemoglobinemia (e.g., hypoxia, cyanosis) when prilocaine is used in combination with other agents associated with development of methemoglobinemia. Avoid lidocaine/prilocaine in infants receiving such agents. Monitor therapy

Sodium Nitrite: Methemoglobinemia Associated Agents may enhance the adverse/toxic effect of Sodium Nitrite. Combinations of these agents may increase the likelihood of significant methemoglobinemia. Monitor therapy

Sodium Picosulfate: Antibiotics may diminish the therapeutic effect of Sodium Picosulfate. Management: Consider using an alternative product for bowel cleansing prior to a colonoscopy in patients who have recently used or are concurrently using an antibiotic. Consider therapy modification

Adverse Reactions

Frequency not defined.

Cardiovascular: Edema, facial edema

Dermatologic: Erythema, maceration, pruritus, rash, urticaria

Endocrine & metabolic: Hyperchloremia, metabolic acidosis

Gastrointestinal: Diarrhea (following accidental ingestion)

Hematologic: Bleeding, bone marrow suppression, DIC, eosinophilia, hemolytic anemia, porphyria

Local: Blisters, burning sensation, excoriation, pain

Respiratory: Dyspnea, hyperventilation, pCO₂ decreased, tachypnea

Miscellaneous: Hypersensitivity

Warnings/Precautions

Concerns related to adverse effects:

• Acid-base imbalance: Mafenide and its metabolite inhibit carbonic anhydrase; metabolic acidosis may occur. Symptoms may include compensatory hyperventilation; risk is increased in patients with impaired renal function. Some patients experience masked hyperventilation and respiratory alkalosis; etiology is unknown. Monitor acid-base balance, especially in patients with extensive second-degree or partial-thickness burns and in patients with pulmonary or renal dysfunction.
• Sulfonamide allergy: Chemical similarities are present among sulfonamides, sulfonylureas, carbonic anhydrase inhibitors, thiazides, and loop diuretics (except ethacrynic acid). Use in patients with sulfonamide allergy is specifically contraindicated in product labeling, however, a risk of cross-reaction exists in patients with allergy to any of these compounds; avoid use when previous reaction has been severe.
• Superinfection: Prolonged use may result in fungal or bacterial superinfection, including C. difficile-associated diarrhea (CDAD) and pseudomembranous colitis; CDAD has been observed >2 months postantibiotic treatment.

Disease-related concerns:

• G6PD deficiency: Use caution in patients with G6PD deficiency; hemolytic anemia with DIC (including fatalities) has been reported with use, presumably related to G6PD deficiency.
• Renal impairment: Use with caution in burn patients with acute renal impairment; accumulation of parent drug and metabolite may enhance carbonic anhydrase inhibition and increase risk of metabolic acidosis.

Concurrent drug therapy issues:

• Drug-drug interactions: Potentially significant interactions may exist, requiring dose or frequency adjustment, additional monitoring, and/or selection of alternative therapy. Consult drug interactions database for more detailed information.

Dosage forms specific issues:

• Sulfites: Some dosage forms contain sulfites which may cause allergic-type reactions (including anaphylaxis) as well as life-threatening or less severe asthmatic episodes in certain individuals; consider discontinuation of therapy if allergic reactions occur.

Monitoring Parameters

Acid base balance; signs of infection; signs of healing

Pregnancy

Pregnancy Considerations

Adverse events were not observed in animal reproduction studies using an oral preparation. The manufacturer does not recommend use of the cream in women of childbearing potential unless the burn area covers >20% of the total body surface or when benefits of treatment outweigh possible risks to the fetus.

Patient Education

• Discuss specific use of drug and side effects with patient as it relates to treatment. (HCAHPS: During this hospital stay, were you given any medicine that you had not taken before? Before giving you any new medicine, how often did hospital staff tell you what the medicine was for? How often did hospital staff describe possible side effects in a way you could understand?)
• Patient may experience short-term pain or burning. Have patient report immediately to prescriber signs of acidosis (confusion, fast breathing, fast heartbeat, abnormal heartbeat, severe abdominal pain, nausea, vomiting, fatigue, shortness of breath, or loss of strength and energy), severe skin irritation, or signs of hemolytic anemia (severe loss of strength and energy, dark urine, or yellow skin) (HCAHPS).
• Educate patient about signs of a significant reaction (eg, wheezing; chest tightness; fever; itching; bad cough; blue skin color; seizures; or swelling of face, lips, tongue, or throat). Note: This is not a comprehensive list of all side effects. Patient should consult prescriber for additional questions.

Intended Use and Disclaimer: Should not be printed and given to patients. This information is intended to serve as a concise initial reference for healthcare professionals to use when discussing medications with a patient. You must ultimately rely on your own discretion, experience and judgment in diagnosing, treating and advising patients.