Some calcium channel antagonists have no effect on the open-field behavior of rats nor do they interact with cocaine.

The behavioral effects of the calcium channel antagonists nifedipine (10 mg/kg), diltiazem (10 mg/kg) and verapamil (10 mg/kg) administered intraperitoneally alone or in combination with the CNS stimulant cocaine (20 mg/kg) were investigated in rats using the open-field test. Calcium channel antagonists alone or combined with cocaine produced no significant effects on the number of rearings or number of ambulations. Cocaine injected alone significantly increased the frequency of ambulation. These data indicate that some calcium channel antagonists were not able to alter the behavioral effects induced by cocaine in rats in the open-field and thus do not support the view that calcium antagonists can reverse the effects of psychostimulant drugs.