CONVERSION FROM 2.5 MG TO 1.25 MG INDAPAMIDE IN PATIENTS WITH MILD-TO-MODERATE HYPERTENSION

Background. Indapamide is an effective antihypertensive drug with diur etic and vasodilating activities. The com mon starting dose has been 2 .5 mg to 5 mg. A lower dose formulation (1.25 mg) is now available. Th e safety and efficacy of switching patients from indapamide 2.5 mg to indapamide 1.25 mg was evaluated in this randomized, double-blind, mul ticenter clinical trial. Methods. Three hundred seventy-eight adult pa tients with mild to moderate essential hypertension were enrolled in a washout period, during which patients received single-blind placebo f or 4 weeks. All 378 patients qualified for the study and received open -label treatment with indapamide 2.5 mg for 8 weeks. Of the 378 patien ts, 265 responded to indapamide 2.5 mg and were randomized to receive double-blind treatment with either indapamide 1.25 mg (n=132) or 2.5 m g (n=133) for 8 weeks. Overall, 245 of the 378 patients who were initi ally enrolled completed the study. The primary efficacy variable was t he number of patients in each treatment group who maintained a supine diastolic blood pressure of less than or equal to 90 mm Hg (treatment success) by the end of the double-blind period (week 16). Results. Tre atment with indapamide 1.25 mg once daily was as efficacious as the 2. 5-mg once-daily dose. No significant difference was observed for the p ercentage of patients who achieved treatment success between the patie nts switched from indapamide 2.5 to 1.25 mg (74%) and the control grou p maintained on indapamide 2.5 mg (70%). The incidence of drug-related adverse events during the double-blind period was similar between the two treatment groups. The mean change from pretreatment baseline to e ndpoint in serum potassium was -0.2 mEq/L (-0.2 mmol/L) in the indapam ide 1.25 mg treatment group, compared with -0.4 mEq/L (-0.4 mmol/L) in the indapamide 2.5 mg treatment group. Conclusions. Indapamide 1.25 m g given once daily for 8 weeks was as effective as 2.5 mg once daily i n reducing systolic and diastolic blood pressure in patients with mild to moderate hypertension.