Tienilic acid in patients with impaired renal function.

Diuretic therapy is usually accompanied by biochemical changes, such as hypokalemia, impaired glucose tolerance and hyperuricaemia. Tienilic acid is a new long-acting diuretic with antihypertensive effect, combined with uricosuric property. For the purpose of evaluating the effect of tienilic acid in patients with impaired renal function, eleven patients with hypertension and slight to moderate renal impairment were randomized to either hydrochlorothiazide or tienilic acid therapy. During eight weeks of treatment no changes occurred in serum-creatinine, creatinine-clearance, serum-sodium, or urea. Despite renal impairment, serum uric acid decreased during tienilic acid treatment. Compared with placebo, a significant decrease in uric acid was seen as early as after one week of treatment (p less than 0.01) and after 8 weeks the difference was still of the same order (p less than 0.01). During hydrochlorothiazide therapy, serum uric acid increased progressively. The difference was p less than 0.002 at 4 weeks and p less than 0.0005 at 8 weeks of treatment, compared with placebo. The results of this study show that the uricosuric effect of tienilic acid is maintained in patients with mild to moderate renal impairment.