Effectiveness and tolerability of once versus twice daily nitrendipine in the treatment of mild to moderate hypertension. The Canadian Nitrendipine Study Group.

Improved measurement of plasma concentrations of nitrendipine demonstrates a plasma half-life of 17 to 21 h allowing once daily dosing for antihypertensive treatment. To determine the effectiveness and tolerability of nitrendipine given once versus twice daily, 78 patients with mild to moderate essential hypertension were randomized in a double-blind fashion to 12 weeks of treatment with either nitrendipine 20 mg once daily (n = 39) or nitrendipine 10 mg bid (n = 39). Blood pressures measured at the end of the dosing interval were similar on 20 mg once daily and 10 mg bid. Adverse events considered to be drug related (flushing and headaches) occurred mostly at the beginning of active treatment and more frequently on the once daily dosing, resulting in a greater number of patients being withdrawn from the once daily treatment group. Thus, nitrendipine 20 mg once daily lowered blood pressure as effectively as 10 mg bid but was associated with a higher incidence of adverse events. These could be minimized by starting at nitrendipine 10 mg once daily and increasing to 20 mg once daily after two to four weeks.

Once- vs. twice-daily nitrendipine in the treatment of mild to moderate hypertension, Canadian Nitrendipine Study Group.

Improved measurement of the plasma concentration of nitrendipine demonstrated a plasma half-life of 17-21 h, allowing once-daily (o.d.) instead of currently twice-daily (b.i.d.) dosing. To determine the effectiveness of nitrendipine given o.d. vs. b.i.d., 78 hypertensive patients, [supine diastolic blood pressure (DBP) of 95-114 mm Hg] were randomized in a double-blind fashion to 12 weeks of treatment with either nitrendipine 10 mg b.i.d. (n = 39) or nitrendipine 20 mg o.d. (n = 39) after a 2-week placebo baseline period. Blood pressures (BPs) were measured in the morning at the end of the dosing interval. Mean +/- SD reduction in supine systolic BP (SBP) and DBP in patients evaluable for efficacy (greater than or equal to 14 days treatment) were 7.2 +/- 16.5 and 7.7 +/- 10.3 mm Hg, respectively, after nitrendipine b.i.d. (n = 38) and 9.4 +/- 15.1 and 9.5 +/- 7.0 mm Hg, respectively, after nitrendipine o.d. (n = 36). Similar falls in BP were found for both regimens in patients completing the full 12 weeks of treatment period (n: o.d. = 28, b.i.d. = 32). Discontinuation due to adverse experiences (AEs) occurred in three patients on b.i.d. and eight patients on o.d., the latter mostly in the first 2 weeks of therapy. Overall, AEs were higher in the o.d. group (% AEs at least possibly related to study medication: o.d. = 44%, b.i.d. = 33%). Most frequent AEs were headache and flushing.(ABSTRACT TRUNCATED AT 250 WORDS)

A study of efficacy, tolerance and compliance of once-daily versus twice-daily metoprolol (Betaloc) in hypertension. Betaloc Compliance Canadian Cooperative Study Group.

The effects of metoprolol (Betaloc tablets) in a group of 193 hypertensives were compared with the effects of a slow-release formulation (Betaloc Durules) in a further group of 196 patients. Patients were selected at random for treatment. There were no differences between the groups in terms of age, weight, sex, blood pressure, concurrent illness or concomitant therapy. Blood pressure control and apparent adverse effects were similar for both groups; the overall withdrawal rate from each group was similar. Compliance, assessed by tablet counts, was significantly improved in the group receiving once-daily therapy. Simplification of the dosage regimen to once-daily therapy appears to improve the patient's willingness to comply with the physician's instructions.