Effects of calcium-antagonists on passive cutaneous anaphylaxis in the rat

The actions of four Ca2+-antagonists (nifedipine, verapamil, diltiazem and D 600) were compared with those of four substances that are used clinically in treating asthma (theophylline, isoproterenol, disodium cromoglycate and clemastine), using the passive cutaneous anaphylaxis (PCA) reaction in the rat. Nifedipine, verapamil and diltiazem produced a partial, but dose-related inhibition of the PCA reaction. A slight, but significant inhibitory effect was also observed with D 600. Isoproterenol, theophylline and disodium cromoglycate also produced dose-related inhibition of the PCA reaction, their maximum effects being greater than those of the Ca2+-antagonists. As the histamine H1-antagonist clemastine was about as active as nifedipine, verapamil or diltiazem in inhibiting the PCA reaction, it seems possible that certain Ca2+-antagonists might be of value in treating allergic disorders in man.