A Comparison of the Anti‐Hypertensive Effectiveness of Two Triameterene/Hydrochlorothiazide Combinations: Maxzide Versus Dyazide

Abstract

The hydrochlorothiazide component of Maxzide (Lederle Laboratories, Pearl River, NY) has been shown to be more bioavailable than the hydrochlorothiazide component of Dyazide (Smith, Kline and French Laboratories, Philadelphia, PA). The authors compared the antihypertensive effectiveness of a half-tablet of Maxzide (25 mg of hydrochlorothiazide and 37.5 mg of triamterene) to one capsule of Dyazide (25 mg of hydrochlorothiazide and 50 mg of triamterene) to determine if the difference in bioavailability would be reflected in differences in blood pressure control and metabolic changes. Thirty patients were studied in a randomized open-label crossover design study. There was a significant reduction in systolic blood pressure for both treatments although there was no difference in blood pressures at any time during the study between the two agents. There were no statistically significant differences between Maxzide and Dyazide in terms of metabolic changes for potassium, magnesium, glucose, cholesterol, triglycerides, uric acid, or calcium. Although the hydrochlorothiazide component of Maxzide is more bioavailable than that of Dyazide this did not translate into enhanced hypotensive efficacy.

Contemplating the history of drug therapy for hypertension

“…Further evidence of adverse effects of diuretics on diabetes and metabolic parameters showed a deterioration in glucose tolerance [44], plasma glucose [45,46], plasma potassium [47], plasma cholesterol [48] and serum uric acid [49], which perhaps outweighed the modest benefits of treatment afforded by diuretics to patients with mild hypertension. Potassium sparing agents -spironolactone, triamterene and amiloride -succeeded in solving the problem of potassium loss when given together with hydrochlorothiazide in such combinations as aldactazide [50], diazyde [51] and moduretic [52]. Spironolactone alone is used in patients with hyperaldosteronism.…”