Effects of tiapamil, a new calcium channel blocker, on ambulatory intraarterial blood pressure and exercise-induced changes in blood pressure.

The duration and magnitude of effect of a new calcium-channel blocker, tiapamil, given twice daily, was studied in 17 hypertensive patients using ambulatory intraarterial blood pressure recording. The drug produced moderate reductions of blood pressure throughout the 24-h cycle with slight reduction of effect before each dose. Ten patients reported side effects, and one withdrew as a result of these. Tiapamil attenuated the blood pressure rise during dynamic cycle ergometry but had no effect on the increase during isometric hand grip. We conclude that tiapamil is similar to existing calcium-channel blocking agents in lowering the blood pressure, but it does not appear to influence the response to isometric exercise in this dose.