Beta-blocker carteolol and oxprenolol produce cutaneous analgesia in response to needle pinpricks in the rat

BackgroundThis present study was undertaken to determine whether beta-blockers produce the cutaneous analgesic effect, comparing them with the long-acting local anesthetic bupivacaine.MethodsUsing a rat model of infiltrative cutaneous analgesia, the effect of 5 beta-blockers (oxprenolol, carteolol, butaxamine, metoprolol, and acebutolol) and bupivacaine was compared and eventually combined with epinephrine.ResultsAmong 5 beta-blockers, oxprenolol exhibited the most potent and the longest duration of cutaneous analgesia. In dose-response studies, the rank order of efficacy (ED50 [50% effective dose]) was bupivacaine (0.40 [0.35-0.47] mu mol) > oxprenolol (2.33 [2.06-2.64] mu mol) > carteolol (4.86 [4.27-5.53] mu mol) (p< 0.01). Carteolol provoked a longer duration of analgesia (p< 0.01) than oxprenolol or bupivacaine on an equipotent basis (ED25, ED50, and ED75). Adding epinephrine 1:200,000 to drug preparations (carteolol, oxprenolol, and bupivacaine) at ED95 had a peripheral action in prolonging the duration of action.ConclusionsOxprenolol and carteolol had greater potencies and longer durations of cutaneous analgesia than butaxamine, metoprolol, and acebutolol. Oxprenolol produced a similar duration of action when compared to bupivacaine, while carteolol had a greater duration of action than bupivacaine. Cutaneous analgesia of oxprenolol (or carteolol) plus adrenaline was greater than that of bupivacaine plus adrenaline.