The use of cimetidine to reduce dapsone-dependent methaemoglobinaemia in dermatitis herpetiformis patients.

Abstract

1. We have attempted to reduce dapsone-dependent methaemoglobinaemia formation in six dermatitis herpetiformis patients stabilised on dapsone by the co-administration of cimetidine. 2. In comparison with control, i.e. dapsone alone, methaemoglobinaemia due to dapsone fell by 27.3 +/- 6.7% and 26.6 +/- 5.6% the first and second weeks after commencement of cimetidine administration. The normally cyanotic appearance of the patient on the highest dose of dapsone (350 mg day-1), underwent marked improvement. 3. There was a significant increase in the trough plasma concentration of dapsone (2.8 +/- 0.8 x 10(-5)% dose ml-1) at day 21 in the presence of cimetidine compared with control (day 7, 1.9 +/- 0.6 x 10(-5)% dose ml-1, P less than 0.01). During the period of the study, dapsone-mediated control of the dermatitis herpetiformis in all six patients was unchanged. 4. Trough plasma concentrations of monoacetyl dapsone were significantly increased (P less than 0.05) at day 21 (1.9 +/- 1.0 x 10(-5)% dose ml-1) compared with day 7 (1.6 +/- 0.9 x 10(-5)% dose ml-1:control). 5. Over a 12 h period, 20.6 +/- 8.9% (day 0) of a dose of dapsone was detectable in urine as dapsone hydroxylamine. Significantly less dapsone hydroxylamine was recovered from urine at day 14 (15.0 +/- 8.4) in the presence of cimetidine, compared with day 0 (control: P less than 0.05). 6. The co-administration of cimetidine may be of value in increasing patient tolerance to dapsone, a widely used, effective, but comparatively toxic drug.

• Authors: M D Coleman, L E Rhodes, A K Scott, J L Verbov, P S Friedmann, A M Breckenridge, B K Park
• Journal: British journal of clinical pharmacology (Br J Clin Pharmacol) Vol. 34 Issue 3 Pg. 244-9 (Sep 1992) ISSN: 0306-5251 [Print] England
• PMID: 1389948 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Cimetidine
• Dapsone
• monoacetyldapsone

Topics

• Adult
• Aged
• Aged, 80 and over
• Cimetidine (pharmacology, therapeutic use)
• Dapsone (adverse effects, analogs & derivatives, pharmacokinetics, therapeutic use)
• Dermatitis Herpetiformis (complications, drug therapy)
• Drug Therapy, Combination
• Drug Tolerance
• Female
• Humans
• Male
• Methemoglobinemia (chemically induced, drug therapy)
• Middle Aged