CALCIUM-CHANNEL BLOCKERS AND H2-RECEPTOR ANTAGONISTS

The plasma levels of diltiazem, isradipine and nifedipine are increased by cimetidine and it may be necessary to reduce their dosages. High doses of cimetidine may increase the bioavailability of lercanidipine. Although studies suggest no important inter- actions occur between nicardipine or nisoldipine and cimetidine, the manufacturers advise caution. Plasma felodipine, lacidipine, nimodipine, and nitrendipine levels are also increased but this does not seem to be clinically significant.
Monitor concurrent use. If adverse effects (such as hypotension, dizziness, flushing and palpitations) become troublesome decrease the calcium-channel blocker dose.