Efficacy of verapamil in patients resistant to other antihypertensive therapy

A solution of verapamil in sequential intravenous infusion was used in patients with severe arterial hypertension who were resistant to various antihypertensive drug regimens. The infusion--25-mg verapamil diluted in 100-ml glucose and slowly injected over 10 minutes--was given daily until a diastolic pressure less than 100 mm Hg was sustained for more than 24 hours. Then patients were maintained on their conventional oral medication alone. This trial involved 11 patients, 10 of whom had primary hypertension and 1 a renovascular type of secondary hypertension. Normal pressure was maintained in all patients with the conventional medication after the verapamil infusions, which varied from 2 to 10; surprisingly, this situation continued from 30 to 120 days and this result was attributed to resetting of the baroreceptors. To confirm this theory, another group of patients underwent baroreceptor testing with angiotensin before and after the use of verapamil; the baroreceptors were functioning at a lower threshold of excitability after verapamil. We conclude that verapamil is capable of resetting the baroreceptors to a lower level, rendering them responsive to increases in blood pressure.