Treatment of arterial hypertension with tienilic acid, a new diuretic with uricosuric properties.

Tienilic acid--2,3-dichloro-4-(2-thienyl-carbonyl)phenoxyacetic acid--is a new diuretic with uricosuric properties. Nineteen patients with moderate arterial hypertension were treated for 5 consecutive weeks in a randomized fashion in a double-blind study with either tienilic acid or hydrochlorothiazide. Blood pressure was significantly reduced and to the same degree with both drugs. In 7 of the 11 patients receiving tienilic acid the daily dose was increased from 250 to 500 mg after 2 weeks, and in 2 of the 8 patients taking hydrochlorothiazide the daily dose was increased from 50 to 100 mg. Because of the potent uricosuric action of tienilic acid the mean serum urate concentration decreased from 6.3 to 3.3 mg/dL in the patients taking the drug. In contrast, the patients receiving hydrochlorothiazide the mean serum urate concentration increased from 6.1 to 7.8 mg/dL. Moderate hypokalemia of almost identical degree (mean serum potassium values 3.6 and 3.5 mmol/L) and mild metabolic alkalosis were observed in both groups. Tienilic acid had a marked hypocalciuric effect, which was of the same magnitude as the observed with hydrochlorothiazide. During the 5 weeks of treatment no significant change in renal or liver function was observed in either group. There were no hematologic complications and the drug was remarkably well tolerated. Tienilic acid, because of its unique character as a diuretic, hypouricemic and antihypertensive agent, should become the preferred drug for the treatment of arterial hypertension.