Effects of some antihypertensive drugs on cutaneous blood flow and inflammatory skin responses following allergen challenge in guinea pigs.

The effects of the antihypertensive drugs clonidine, prazosin, and MK 422 (the active parent diacid of enalapril) were studied on the cutaneous blood flow and allergen evoked inflammatory skin reactions in ovalbumin sensitized guinea pigs. The hypotensive effect of the drugs did not significantly change the basal cutaneous blood flow at the time of allergen challenge. MK 422 (0.02 mg/kg) markedly enhanced the wheal and flare reaction following allergen challenge, whereas clonidine (0.005 and 0.05 mg/kg) inhibited the inflammatory response. Prazosin (0.03 mg/kg) did not significantly influence the wheal and flare reaction. Our results indicate that some antihypertensive drugs (clonidine) could be beneficial to antihypertensive patients with inflammatory diseases, while others (ACE-inhibitors) may enhance their inflammatory disorders.