BETA BLOCKERS AND CALCIUM-CHANNEL BLOCKERS - DILTIAZEM

The cardiac depressant effects of diltiazem and beta blockers are additive, although concurrent use can be beneficial. A number of patients, usually those with pre-existing ventricular failure or conduction abnormalities, have developed serious and poten- tially life-threatening bradycardia.
Monitor the outcome of concurrent use for additive haemodynamic effects (e.g. bradycardia, hypotension or heart failure).