Isradipine and other calcium channel antagonists attenuate ethanol consumption in ethanol-preferring rats.

The present work is concerned with studying of the ability of different calcium channel antagonists to modify voluntary ethanol ingestion by rats selectively bred for high ethanol preference. The compounds were given s.c. thrice daily for 5 days at doses that did not produce locomotor impairment. While nifedipine, darodipine, and verapamil (each at the dose of 20 mg/kg thrice daily) produced a modest reduction in ethanol intake, isradipine (at the dose of 1 mg/kg three times a day) reduced ethanol intake by over 70%. For all compounds, the reduction in ethanol intake was compensated by a proportional increase in water consumption and the inhibitory effect persisted throughout the 5 days of treatment. The data indicate that calcium channel antagonists exhibit quite different potency in reducing ethanol preference, however this action is a general property of this class of compounds.