Comparison of the Effects on Ambulatory Blood Pressure of Awakening versus Bedtime Administration of Torasemide in Essential Hypertension

Torasemide is a high-ceiling loop diuretic frequently used in the treatment of congestive heart failure, renal failure, and hypertension. Low doses of torasemide (2.5 to 5 mg/day) do not elevate 24 h natriuresis, and they constitute effective monotherapy for mild-to-moderate uncomplicated essential hypertension according to results based on clinic blood pressure (BP). However, there has yet to be a proper evaluation of its 24 h efficacy or potential dependency of effects according to the circadian time of treatment. Accordingly, this trial investigated the administration time-dependent efficacy of torasemide in uncomplicated essential hypertensive patients. We studied a total of 113 grade 1 and 2 hypertensive patients, 51.7+/-10.6 yrs of age, randomly assigned to receive torasemide (5 mg/day) as a monotherapy either upon awakening or at bedtime. BP was measured by ambulatory monitoring for 48 consecutive hours before and after six weeks of treatment. The efficacy of torasemide was significantly greater with bedtime dosing (i.e., 14.8 and 9.5 mmHg reduction in the 24 h mean systolic and diastolic BP, respectively) as compared with morning dosing upon awakening (i.e., 6.4 and 3.4 mmHg reduction in mean systolic and diastolic BP; p<0.001 between the two treatment-time groups). The percentage of patients with controlled ambulatory BP after treatment was also higher after bedtime treatment (64 vs. 23%; p<0.001). Safety and tolerability were comparable between the two treatment-time groups. A dose of 5 mg/day torasemide is more effective for BP reduction for uncomplicated essential hypertensive patients when ingested at bedtime than in the morning upon arising. The difference in antihypertensive efficacy as a function of the circadian dosing-time of torasemide here documented should be taken into account when prescribing this loop diuretic to treat essential hypertensive patients.