The role of a slow channel inhibitor, verapamil, in the management of hypertension.

The 'Oxford' system for continuous monitoring of the ambulatory blood pressure was used to assess the changes in blood pressure following therapy with the slow channel inhibitor, verapamil. Sixteen patients were studied on no therapy and following a minimum of 6 weeks therapy (dose range 120-160 mg t.d.s.). During each study patients underwent standardized physiological tests including tilt, isometric handgrip and dynamic bicycle exercise. Verapamil was demonstrated to produce a consistent reduction of blood pressure over most of the 24 h period studied but this was most marked during the day. Heart rate was also reduced. There was no postural hypotension and the absolute responses to dynamic and isometric exercise were reduced. The results demonstrate the antihypertensive efficacy of 'slow channel inhibitors' as represented by verapamil.