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dapsone (Avlosulfon)

Tradename: Avlosulfon. Indications: - dermatitis herpetiformis - pyoderma gangrenosum [7] - subcorneal pustular dermatosis - pemphigoid - cicatricial pemphigoid [7] - granuloma annulare - connective tissue disease - vasculitis - leprosy - Pneumocystis carinii pneumonia - pneumocystis pneumonia prophylaxis - mycetoma [7] - Toxoplasmosis [7] - topical treatment of acne vulgaris [6] - chronic idiopathic urticaria & autoimmune urticaria (2nd line) [9] Contraindications: Caution: 1) patients with severe anemia 2) glucose-6-phosphate dehydrogenase activity Dosage: - dermatitis herpetiformis: 50-300 mg PO QD - leprosy: 50-100 mg/day for 3-10 years - Pneumocystis carinii pneumonia a) prophylaxis: 100 mg PO QD b) treatment: 100 mg PO QD in combination with trimethoprim 20 mg/kg/day for 21 days Tabs: 25 & 100 mg. Aczone: topical gel for acne Pharmacokinetics: 1) well absorbed following oral administration 2) metabolized in the liver by cyt P450 3A4 3) 1/2life 20-30 hours 4) elimination a) 20% unchanged in the urine b) 70-85% as metabolites in the urine Dosage adjustment in renal failure: - dose adjustment may be necessary with renal impairment. - no specific guidelines available Monitor: - G6PD in erythrocytes to rule out G6PD deficiency - not necessary with topical dapsone - screening for HLA-B*1301 allele recommended prior to dapsone therapy in Asians [8] Adverse effects: 1) not common (1-10%) a) dose related hemolysis in patients with & without G6PD deficiency b) methemoglobinemia with cyanosis 2) uncommon (< 1%) - peripheral neuropathy, insomnia, headache - exfoliative dermatitis - anemia, leukopenia, agranulocytosis - nausea/vomiting, hepatitis, cholestatic jaundice - blurred vision, tinnitus 3) adverse cutaneous reaction in Asians with HLA-B*1301 allele [8] Drug interactions: 1) rifampin lowers blood levels of dapsone by increasing clearance 2) folate antagonists such as pyrimethamine may increase likelihood of hematologic reactions 3) PABA may decrease effectiveness 4) didanosine (ddI) in combination decreases effect of dapsone; administer 2 hours apart 5) trimethoprim in combination may increase both dapsone & trimethoprim levels 6) clofazimine in combination may decrease effective of dapsone 7) any drug that inhibits cyt P450 3A4 may increase levels of dapsone 8) any drug that induces cyt P450 3A4 may diminish levels of dapsone Mechanism of action: 1) competitive antagonist of para-aminobenzoic acid (PABA) 2) prevents bacterial utilization of PABA for synthesis of folate

Interactions

drug interactions drug adverse effects of sulfonamides

Related

cytochrome P450 3A4 (cytochrome P450 C3, nifedipine oxidase, P450-PCN1, NF-25, CYP3A4) dermatitis herpetiformis; Duhring-Brocq disease leprosy (Hansen's disease) para-aminobenzoic acid; 4-aminobenzoic acid (PABA, Paraben, Potaba)

Specific

Dapsone Topical (Aczone)

General

disease-modifying antirheumatic agent (DMARD) sulfonamide

Properties

MISC-INFO: elimination route LIVER 75% KIDNEY 20% 1/2life 20-30 HOURS pregnancy-category C safety in lactation -

Database Correlations

PUBCHEM cid=2955

References

  1. The Pharmacological Basis of Therapeutics, 9th ed. Gilman et al, eds. Permagon Press/McGraw Hill, 1996
  2. Drug Information & Medication Formulary, Veterans Affairs, Central California Health Care System, 1st ed., Ravnan et al eds, 1998
  3. Kaiser Permanente Northern California Regional Drug Formulary, 1998
  4. Medical Knowledge Self Assessment Program (MKSAP) 11, 18. American College of Physicians, Philadelphia 1998, 2018
  5. Prescriber's Letter 13(2): 2006 Detail-Document#: 220215 (subscription needed) http://www.prescribersletter.com
  6. Prescriber's Letter 16(1): 2009 COMMENTARY: New Drug: Aczone (Dapsone) Gel 5% GUIDELINES: Acne Vulgaris Management GUIDELINES: Recommendations for Acne Management Detail-Document#: 250112 (subscription needed) http://www.prescribersletter.com
  7. Deprecated Reference
  8. Tangamornsuksan W, Lohitnavy M. Association Between HLA-B*1301 and Dapsone-Induced Cutaneous Adverse Drug Reactions. A Systematic Review and Meta-analysis. JAMA Dermatol. 2018 Mar 14. PMID: 29541744
  9. Liang SE, Hoffmann R, Peterson E et al. Use of dapsone in the treatment of chronic idiopathic and autoimmune urticaria. JAMA Dermatol 2018 Nov 21; 155:90. PMID: 30476976 https://jamanetwork.com/journals/jamadermatology/fullarticle/2715087