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Hydrochlorothiazide is not additive to verapamil in treating essential hypertension
J P Nicholson1, L M Resnick, J H Laragh
1Cardiovascular Center, New York Hospital-Cornell Medical Center, New York 10021.
Insights
Adding hydrochlorothiazide to verapamil did not further lower blood pressure in patients with essential hypertension. This combination therapy may not be beneficial for managing hypertension.
Area of Science:
- Cardiology
- Pharmacology
Background:
- Calcium channel blockers are effective antihypertensive agents, especially in low renin hypertension.
- Thiazide diuretics are also effective, particularly in low renin hypertension.
Purpose of the Study:
- To investigate the additive antihypertensive effect of thiazide diuretics when combined with calcium channel blockers.
Main Methods:
- An open study involving 13 patients with mild to moderate essential hypertension.
- Patients received verapamil hydrochloride (360 mg/d) or hydrochlorothiazide (25 mg/d) alone and in combination.
Main Results:
- Both verapamil and hydrochlorothiazide monotherapy lowered blood pressure.
- Combining hydrochlorothiazide with verapamil showed no additional blood pressure reduction.
- Hydrochlorothiazide decreased serum potassium and increased plasma renin activity; verapamil had minimal effects on renin and no effect on potassium.
Conclusions:
- Concurrent diuretic therapy with verapamil may not offer additional antihypertensive benefits in essential hypertension.
- The findings suggest that combining verapamil with hydrochlorothiazide is not warranted for essential hypertension management.
Abstract:
Calcium channel blockers, a newer class of antihypertensive medications, have gained considerable acceptance as monotherapeutic agents, particularly in low renin hypertension where diuretics are also most effective. To study whether thiazide diuretics exert an additional antihypertensive effect in the setting of calcium channel blockade, we gave verapamil hydrochloride (360 mg/d) or hydrochlorothiazide (25 mg/d) alone and in combination in an open study to 13 hypertensive patients with mild to moderate essential hypertension. Both verapamil and hydrochlorothiazide lowered blood pressure (170 +/- 17/109 +/- 6 mm Hg pretreatment to 150 +/- 25/95 +/- 8 mm Hg with verapamil; 170 +/- 5/109 +/- 2 mm Hg pretreatment to 164 +/- 25/103 +/- 10 mm Hg with hydrochlorothiazide), but addition of hydrochlorothiazide to verapamil resulted in no added benefit (150 +/- 25/95 +/- 8 mm Hg vs 150 +/- 20/95 +/- 6 mm Hg). Furthermore, while hydrochlorothiazide lowered serum potassium values (4.2 +/- 0.25 mmol/L to 3.7 +/- 0.35 mmol/L) and stimulated plasma renin activity (1.5 +/- 1.3 ng/mL/h) pretreatment to 3.3 +/- 2.7 ng/mL/h with verapamil), verapamil only modestly elevated renin activity (1.5 +/- 1.3 ng/mL/h pretreatment to 2.7 +/- 2.5 ng/mL/h with verapamil) and did not lower potassium values. Altogether, the data suggest that in essential hypertension, at least for verapamil, concurrent diuretic therapy may not be helpful or warranted.