The cardiac depressant effects of
verapamil and
beta blockers are additive, and although concurrent use can be beneficial, serious cardiodepression (bradycardia, asystole, sinus arrest) sometimes occurs. An adverse interaction can occur even with
beta blockers given as eye drops.
Concurrent use should only be undertaken if the patient can initially be closely monitored. The doses should be carefully titrated to effect. It has been suggested that
verapamil injections should not be given to patients recently given
beta blockers because of the risk of hypotension and asystole.