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Cimetidine's effect on dermal H1-receptor antagonist tolerance
British Journal of Clinical Pharmacology
|February 1, 1985
Summary
Histamine skin reactions can become tolerant to H1-receptor antagonists like clemastine. Adding an H2-receptor antagonist, cimetidine, did not overcome this tolerance, suggesting limited efficacy in such cases.
Area of Science:
- Pharmacology
- Dermatology
- Allergy and Immunology
Background:
- Histamine-induced skin reactions (weal and flare) are common.
- Tolerance to H1-receptor antagonists can develop with prolonged use.
- The potential for cross-tolerance or additive effects with H2-receptor antagonists is not fully understood.
Purpose of the Study:
- To investigate the effect of cimetidine (an H2-receptor antagonist) on histamine-induced weal and flare responses tolerant to clemastine (an H1-receptor antagonist).
Main Methods:
- Nine healthy male subjects received clemastine (1 mg orally twice daily) for 21 days.
- Histamine-induced weal and flare responses were measured before and after clemastine therapy.
- The effect of a single 400 mg dose of cimetidine was assessed on both tolerant and non-tolerant responses.
Main Results:
- Clemastine therapy led to tolerance in the weal response but not the flare response.
- Cimetidine did not significantly reduce the tolerant weal response compared to the non-tolerant response.
Conclusions:
- Histamine-mediated skin reactions can develop tolerance to H1-receptor antagonist therapy.
- Adding an H2-receptor antagonist (cimetidine) does not appear to overcome this established tolerance to H1-receptor antagonists.