Dapsone

Indications

Dapsone is indicated for the topical treatment of acne vulgaris in patients 12 years of age and older.

Pharmacology

Dapsone has both anti-infammatory and antimicrobial properties. A combination of these activities may account for its efcacy in acne. Anti-infammatory efects include inhibition of neutrophil myeloperoxidase and eosinophil peroxidase activity, suppression of hypochlorous acid production, scavenging of reactive oxygen species, suppression of neutrophil activity, and inhibition of chemoattractant-induced signal transduction. Antimicrobial activity, similar to that of sulfones and sulfonamides, is by inhibition of bacterial dihydropteroate synthase in the folic acid metabolic pathway. This mechanism is efective against microorganisms synthesizing their own folic acid. In vitro susceptibility testing has demonstrated some activity for Dapsone against Propionibacterium species, including Propionibacterium acnes (P. acnes).

Dosage & Administration

  • Apply once daily (7.5% gel) and twice daily (5% gel) after the skin is gently washed and patted dry
  • Apply approximately a pea-sized amount of gel in a thin layer to the acne affected area
  • Rub the gel gently and completely
  • If there is no improvement after 12 weeks, treatment with this gel should be reassessed
  • Dapsone gel maybe gritty with visible drug substance particles
  • Wash hands after application

Interaction

Trimethoprim/ sulfamethoxazole (TMP/ SMX) increases the systemic level of Dapsone and its metabolites. Topical benzoyl peroxide used at the same time as Dapsone may result in temporary local yellow or orange skin discoloration.

Contraindications

Those who are hypersensitive to Dapsone.

Side Effects

Oiliness/peeiing, dryness and erythema at the application site.

Pregnancy & Lactation

Pregnancy Category C. There are no adequate and well controlled studies in pregnant women. Dapsone has been shown to have an embryocidal effect in rats and rabbits. These effects were probably secondary to maternal toxicity. Dapsone Gel should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Although systemic absorption of dapsone following topical application Dapsone Gel is minimal relative to oral dapsone administration, it is known that dapsone is excreted in human milk. Because of the potential for oral dapsone to cause adverse reactions in nursing infants, a decision should be made whether to discontinue nursing or to discontinue Dapsone Gel, taking into account the importance of the drug to the mother.

Precautions & Warnings

Methemoglobinemia: Cases of Methemoglobinemia have been reported. Discontinue Dapsone Gel if signs of Methemoglobinemia occur.

Hematologic Effects: Some subjects with Glucose Phosphate Dehydrogenase (G6PD) deficiency using Dapsone Gel developed laboratory changes suggestive of hemolysis.

Use in Special Populations

Pediatric Use: Safety and efectiveness of Dapsone have not been established in pediatric patients below the age of 12 years.

Geriatric Use: Clinical trials of Dapsone did not include sufcient numbers of subjects aged 65 years and over to determine whether they respond diferently from younger subjects.

Therapeutic Class

Acne treatment preparations

Storage Conditions

Store at or below 30°C temperature. Keep away from light and wet place. Keep out of reach of children.