ANTINOCICEPTIVE EFFECTS OF H1-ANTIHISTAMINICS AND H2-ANTIHISTAMINICS IN MICE

1. Two methods were used to study the analgesic effects of subcutaneou s injections of antihistaminics in mice: the p-benzoquinone(PBQ)-writh ing test and caudal compression test. 2. Mepyramine, lupitidine (SKF 9 3479), and famotidine produced significant antinociceptive effects dos e-dependently, during both the PBQ-writhing and caudal compression tes ts. 3. However, ranitidine did not reveal any antinociceptive effect. 4. Icotidine (SKF 93319) produced significant antinociception and also augmented the analgesic effect of morphine, on the caudal compression test. 5. However, mepyramine, famotidine, and lupitidine did not affe ct morphine-induced analgesia on the caudal compression test and displ ayed a nonsignificant potentiation on morphine-induced analgesia in th e PBQ-writhing test.