Felodipine versus Moduretic. A double-blind parallel-group multicentre study

A comparison of isradipine and felodipine in Australian patients with hypertension: focus on ankle oedema. The Physician's Study Group

The aim of this study was to compare the tolerability and efficacy of isradipine and felodipine in the treatment of mild-moderate hypertension. After a 4 week placebo period, 143 patients entered a randomized, double-blind, multicentre study of 12 weeks duration. Patients received either isradipine (n = 72) or felodipine (n = 71) 2.5 mg twice daily. Doubling of this dose and the addition of enalapril (2.5 mg once daily) was permitted if DBP was > 90 mmHg at weeks 4 and 8, respectively. Isradipine monotherapy reduced BP from 165/104 +/- 13/6 mmHg at baseline to 149/91 +/- 14/10 mmHg at week 8 (p < 0.001), while felodipine alone reduced BP from 171/104 +/- 17/6 at baseline to 151/92 +/- 19/9 (p < 0.001). Following the addition of enalapril to 35% of patients in the isradipine group BP was further reduced to 144/88 +/- 13/8 mmHg at week 12 (p < 0.001). The addition of enalapril to 24% of the felodipine group further reduced BP to 150/92 +/- 19/9 mmHg at week 12 (p < 0.001). No differences in BP were found between the 2 groups while on monotherapy. However, the isradipine group had a significantly lower DBP than the felodipine group at the conclusion of the study (p = 0.008; 95% CI 0.7 to 6.9 mmHg). Similar incidences of headache, flushing, dizziness and tachycardia were reported in both groups. However, the incidence of ankle oedema was significantly lower in the isradipine group (p = 0.028). Overall, ankle oedema was reported more often by female patients and was not associated with an increase in weight.(ABSTRACT TRUNCATED AT 250 WORDS)

Dose-response relationships with antihypertensive drugs

A variety of antihypertensive drugs have been introduced into clinical practice at excessively high dose. Examples include most thiazide diuretics, propranolol, oxprenolol, atenolol, methyldopa, hydralazine and captopril. These very high doses have usually resulted from studies in which doses have been increased at regular intervals until the desired antihypertensive effect has been achieved or until unacceptable adverse effects have resulted. Frequently the starting doses were too high and the intervals between dose adjustment too short. In many cases these large doses resulted in unnecessary adverse effects--the adverse biochemical effects of thiazide diuretics, nephrotic syndrome, taste disturbances and neutropenia with captopril, the lupus syndrome with hydralazine and the central nervous system effects of methyldopa. Parallel group design with single doses and sufficient statistical power to distinguish between the upper and lower ends of the antihypertensive dose-response relationship should replace the dose-escalating design.

Felodipine: a new dihydropyridine calcium-channel antagonist

Felodipine, a dihydropyridine calcium-channel antagonist, significantly reduces systolic and diastolic blood pressure (BP) in patients with hypertension and has been associated with beneficial hemodynamic effects in patients with chronic stable angina pectoris or congestive heart failure (CHF). In hypertensive patients, felodipine does not appear to significantly affect glomerular filtration rate, creatinine clearance, glucose tolerance, or plasma lipoprotein concentrations. Studies comparing felodipine with other agents as monotherapy in mild to moderate hypertension have demonstrated felodipine to be at least as efficacious as hydrochlorothiazide (HCTZ) and HCTZ plus amiloride hydrochloride in combination. Comparisons of felodipine with other agents as adjuncts to beta-blocker or diuretic therapy have shown felodipine to be at least as effective as HCTZ, propranolol hydrochloride, prazosin hydrochloride, and nifedipine. Evaluations of patients with chronic stable angina are limited, and additional studies are needed before felodipine can be recommended for the routine management of angina pectoris. Similarly, additional studies are essential to delineate the role of felodipine, if any, in the management of CHF. In the management of hypertension, felodipine 5-40 mg/d significantly reduces systolic and diastolic BP. Although some patients may be controlled throughout the entire dosing interval when felodipine is administered bid, many patients will require more frequent dosing to obtain adequate BP control. Adverse effects associated with felodipine are similar to those of other dihydropyridine calcium-channel antagonists and include peripheral edema, headache, dizziness, flushing, and fatigue. A potentially clinically important drug interaction was observed when felodipine was administered concomitantly with theophylline aminopropanol; significant decreases in theophylline concentrations were noted. In summary, felodipine appears to be safe and effective for the management of hypertension when used alone or in combination with other antihypertensive agents. The efficacy of felodipine in the management of chronic stable angina pectoris and CHF requires further investigation.

Comparison of once daily felodipine 10 mg ER and hydrochlorothiazide 25 mg in the treatment of mild to moderate hypertension

The efficacy of extended release felodipine 10 mg (ER) o.d., a new dihydropyridine calcium antagonist, and 25 mg hydrochlorothiazide (HCTZ) o.d. have been compared in a randomized, double-blind, crossover trial in 28 mildly to moderately hypertensive subjects (supine diastolic blood pressure, BP, greater than or equal to 95 mm Hg and less than or equal to 110 mm Hg on three separate occasions). Both drugs significantly reduced systolic and diastolic BP in the sitting position felodipine from 157.1/93.8 mm Hg at baseline to 133/78.9 mm Hg 2.5 h after medication and to 138/82.7 mm Hg after 2 weeks of treatment, and HCTZ from 156/95.6 mm Hg to 147/88.4 mm Hg 2.5 h after medication and to 149/89.5 mm Hg also after 2 weeks. A decrease of the same magnitude in standing systolic and diastolic BP was observed after both treatment regimens with the exception of diastolic BP 2.5 h after dosing with HCTZ, which was not significantly lower. At all times (2.5 h and 2 weeks), the reduction in systolic and diastolic BP was greater after felodipine compared to HCTZ. Heart rate was significantly increased after felodipine in both the sitting and standing positions, and both 2.5 h following medication and after 2 weeks of treatment. The difference between the regimens was significant only 2.5 h after dosing. Overall, felodipine 10 mg ER o.d. was superior to 25 mg HCTZ o.d. in lowering BP.

Control of blood pressure in hypertensive patients with felodipine extended release or nifedipine retard

1. This multicentre hospital study compared the antihypertensive efficacy and the tolerability of once daily felodipine extended release (ER) with twice daily nifedipine retard (R) in hypertensive patients inadequately controlled on metoprolol monotherapy. 2. One hundred patients, aged 20-70 years, whose seated diastolic blood pressure was 100-115 mmHg after 4 to 6 weeks of metoprolol (200 mg day-1) monotherapy, were randomised, double-blind, to receive felodipine ER 10 mg once daily or nifedipine R 20 mg twice daily for 8 weeks. The dosage of felodipine or nifedipine was doubled if seated diastolic blood pressure exceeded 95 mmHg, 2 or 4 weeks after randomisation. Metoprolol 200 mg once daily was taken throughout the trial. 3. Fifty-one patients received felodipine ER and 49 nifedipine R; 46 and 45 respectively completed the 8 week trial. About half of patients on each treatment needed the higher dose. The baseline characteristics of the felodipine and nifedipine groups were generally well balanced. 4. Seated diastolic blood pressure was reduced by 17 mmHg for felodipine (24 h post-dose) and by 9 mmHg for nifedipine (12 h post-dose), a difference between treatments of 8 mmHg (95% confidence interval 5 to 12 mmHg, P less than 0.0001). The attained blood pressures at the end of the study (felodipine 90 +/- 10, mmHg, mean +/- s.d.; nifedipine 95 +/- 10) were also significantly different (95% confidence interval for the 5 mmHg difference, -9 to -1 mmHg, P less than 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)