24-hour blood pressure control by once-daily administration of irbesartan assessed by ambulatory blood pressure monitoring. Irbesartan Multicenter Investigators' Group.

OBJECTIVES: To compare 24 h ambulatory blood pressure and trough office blood pressure lowerings after 8 weeks of therapy with 75 mg irbesartan once a day, 150 mg irbesartan once a day , and 75 mg irbesartan twice a day versus placebo; and to assess safety and tolerability of irbesartan therapy. DESIGN: Multicenter, double-blind, randomized, placebo-controlled trial. SETTING: Sixteen centers in Italy. PATIENTS: Caucasian patients (n = 215) aged > or = 18 years with seated diastolic blood pressure 95-110 mmHg and ambulatory diastolic blood pressure (ADBP) > or = 85 mmHg. PRIMARY OUTCOME: Mean 24 h ADBP after 8 weeks of irbesartan therapy. RESULTS: Mean changes (value before treatment minus value after treatment) in ADBP for placebo, 75 mg irbesartan once a day, 150 mg irbesartan once a day, and 75 mg irbesartan twice a day were -0.2, -5.4, -7.2, and -7.2 mmHg, respectively; respective changes in ambulatory systolic blood pressure were +1.6, -8.3, -10.5, and -9.7 mmHg. All irbesartan regimens reduced trough office seated diastolic blood pressure and seated systolic blood pressure after 2 and 8 weeks of treatment (all P < 0.01, versus placebo except for seated systolic blood pressure in patients in the 75 mg irbesartan once a day group). Trough: peak ratios were > or = 55% with 150 mg irbesartan once a day. Percentages of patients whose blood pressures were normalized with 150 mg irbesartan once a day (45%) and 75 mg irbesartan twice a day (47%) were greater than those with placebo (14%, P < 0.01) and with 75 mg irbesartan once a day (19%, NS, versus placebo). Adverse events with irbesartan were similar to those with placebo. CONCLUSIONS: All irbesartan regimens significantly reduced mean 24 h ADBP and ambulatory systolic blood pressure, and were well tolerated. Administration of 150 mg irbesartan once a day provided significant reduction of blood pressure for 24 h, equivalent to that obtained with the same daily dose divided into two separate administrations.

Trough:peak ratio of nifedipine gastrointestinal therapeutic system and nifedipine retard in essential hypertensive patients: an Italian multicentre study.

OBJECTIVE: To evaluate the antihypertensive effect of nifedipine gastrointestinal therapeutic system and retard in terms of trough:peak ratio efficacy. METHODS: According to a double-blind, randomized, crossover design, 58 patients with mild-to-moderate essential hypertension, after 1 month placebo washout, received 30 mg/day nifedipine gastrointestinal therapeutic system, 20 mg nifedipine retard twice a day and the corresponding placebos for 1 month. At the end of each treatment period, blood pressure was measured by using a mercury sphygmomanometer at trough and 1, 2, 3 and 4 h after the last dosing. The peak effect was identified as the maximum decrement induced by the three randomized treatments with respect to the value at the end of the placebo washout period during the 4 h interval. The trough:peak ratios of systolic and diastolic blood pressure were calculated as group ratios and individual ratios from decrements induced by nifedipine gastrointestinal therapeutic system and retard, corrected for those induced by randomized placebo. Patients were defined as responders to each randomized treatment if their diastolic blood pressure at trough time was reduced by at least 10 mmHg relative to that at the corresponding time at the end of placebo washout. RESULTS: Nifedipine gastrointestinal therapeutic system and retard significantly reduced blood pressure to a similar extent both at trough and at peak. Systolic and diastolic group trough:peak ratios in responders to nifedipine gastrointestinal therapeutic system (n = 41) were 0.80 and 0.88, respectively, and those in responders to nifedipine retard (n = 30) 0.84 and 0.93, respectively. The percentage of patients with trough:peak ratios > 0.50 was > 80% (systolic trough:peak ratios) and above 90% (diastolic trough: peak ratios) for both nifedipine formulations. CONCLUSIONS: Our data show that 30 mg/day nifedipine gastrointestinal therapeutic system and 20 mg nifedipine retard twice a day have a favourable trough:peak ratios efficacy when given as monotherapy to essential hypertensive patients.