Amlodipine, a calcium channel inhibitor, and cocaine and ethanol's reinforcing effects.

The effects of amlodipine (from 0.1 to 3.0 mg/kg) on rats' pressing for rewarding brain stimulation, with and without cocaine administration, were assessed. None of the doses reliably modified the effects of cocaine. Also, amlodipine was given to two groups of rats taking alcohol: one group that was regularly taking a sweetened alcoholic beverage and the other taking an unsweetened alcoholic beverage. The only discernible effects of amlodipine on alcohol intake were associated with the highest dose and only with rats taking the sweetened beverage. The effects of this high dose could easily be attributable to behavioral toxicity elicited by the dose. In contrast, and confirming previous work, isradipine, another calcium channel inhibitor, produced reliable reductions on both cocaine's and alcohol's reinforcing effects. Despite the similarity of isradipine and amlodipine, isradipine apparently has some unique features with respect to cocaine and alcohol.