NO DEVELOPMENT OF TOLERANCE TO ANALGESIA BY REPEATED ADMINISTRATION OF H-1 ANTAGONISTS

The effect produced by repeated administration of the H-1-antihistamin ics diphenhydramine, promethazine and pyrilamine on their ability to i nduce antinociception was evaluated in the mouse hot-plate and abdomin al constriction tests. Contrary to morphine, baclofen and oxotremorine , the three H-1 antagonists investigated did not promote the developme nt of tolerance to the analgesic effect after 14 days of repeated trea tment. H-1 antagonists could, therefore, represent a promising pharmac ological approach to the management of chronic pain. (C) 1998 Elsevier Science Inc.