Once-daily amlodipine in the treatment of mild to moderate hypertension

Effect of amlodipine on systolic blood pressure

BACKGROUND

Systolic hypertension is the most common form of hypertension, particularly in people aged >60 years. Caused by decreased compliance of large arteries, systolic hypertension is an independent risk factor for cardiovascular disease. Recent studies have demonstrated that it is more important to control systolic blood pressure (SBP) than diastolic blood pressure (DBP).

OBJECTIVE

The objective of this study was to perform a systematic literature review to examine the effectiveness of amlodipine in lowering SBP in a variety of patient subgroups and clinical settings.

METHODS

The literature review methodology included identifying, selecting, appraising, extracting, and synthesizing primary research studies. Following an a priori protocol, published literature was searched from 1980 to 2001 using 3 electronic databases. A manual review of the reference lists of recent review articles and all accepted studies was performed. Parallel-group, randomized, controlled trials that included at least 10 adults with baseline hypertension (SBP>or=140 mm Hg, DBP>or=90 mm Hg, or both), included at least 1 arm randomized to initial treatment with amlodipine monotherapy, had a minimum treatment duration of 8 weeks, and reported baseline and end-point blood pressure were included.

RESULTS

Of 696 citations identified, 85 primary studies met all inclusion criteria. Comparable treatment arms were pooled, and weightd mean SBP was calculated. In the amlodipine monotherapy arms, which included >5000 patients, SBP decreased by a mean of 17.5 mm Hg from baseline. The effect of amlodipine in reducing SBP was greater in elderly patients (age>or=60 years) and patients with author-defined isolated systolic hypertension. The dose was titrated to achieve the target blood pressure in 73 of 89 amlodipine treatment arms, whereas 16 treatment arms reported fixed doses. The median daily dose was 5 mg (range, 1.25-15 mg) in both the fixed-dose and dose-titration groups.

CONCLUSIONS

In this review of the published literature, amlodipine monotherapy was effective in reducing SBP. Antihypertensive agents such as amlodipine warrant consideration for the management of patients with inadequately controlled SBP.

Efficacy of amlodipine in pediatric bone marrow transplant patients

The calcium antagonist amlodipine may have the potential for expanded use in children owing to its physiochemistry and pharmacokinetic profile that facilitates once-daily dosing in a liquid formulation. Its safety and efficacy have not been previously evaluated in children. A retrospective analysis of 15 pediatric bone marrow transplant patients who had amlodipine incorporated into their antihypertensive drug regimen reveals significantly lower blood pressure as compared with baseline therapy (123.5+/-2.1 mmHg and 117.2+/-2.2 mmHg, systolic blood pressure before and during amlodipine, P<0.05; 81.5+/-1.8 mmHg and 75.5+/-2.6 mmHg, diastolic blood pressure before and during amlodipine, P<0.05). Amlodipine provided improved blood pressure control in this cohort and may provide a valuable pharmacologic alternative for treatment of pediatric hypertension.

Valsartan, a new angiotensin II antagonist for the treatment of essential hypertension: a comparative study of the efficacy and safety against amlodipine

OBJECTIVE

To compare the antihypertensive efficacy of a new angiotensin II antagonist, valsartan, with a reference therapy, amlodipine.

METHODS

One hundred sixty-eight adult outpatients with mild to moderate hypertension were randomly allocated in double-blind fashion and equal number to receive 80 mg valsartan or 5 mg amlodipine for 12 weeks. After 8 weeks of therapy, in patients whose blood pressure remained uncontrolled, 5 mg amlodipine was added to the initial therapy. Patients were assessed at 4, 8, and 12 weeks. The primary efficacy variable was change from baseline in mean sitting diastolic blood pressure at 8 weeks. Secondary variables included change in sitting systolic blood pressure and responder rates.

RESULTS

Both valsartan and amlodipine were effective at lowering blood pressure at 4, 8, and 12 weeks. Similar decreases were observed in both groups, with no statistically significant differences between the groups for any variable analyzed. For the primary variable the difference was 0.5 mm Hg in favor of valsartan (p = 0.68; 95% confidence interval, -2.7 to 1.7). Responder rates at 8 weeks were 66.7% for valsartan and 60.2% for amlodipine (p = 0.39). Both treatments were well tolerated. The incidence of drug-related dependent edema was somewhat higher in the amlodipine group, particularly at a dose of 10 mg per day (2.4% for 80 mg valsartan; 3.6% for 5 mg amlodipine; 0% for valsartan plus 5 mg amlodipine; 14.3% for 10 mg amlodipine).

CONCLUSIONS

The data show that valsartan is at least as effective as amlodipine in the treatment of mild to moderate hypertension. The results also show valsartan to be well tolerated and suggest that it is not associated with side effects characteristic of this comparator class, dihydropyridine calcium antagonists.

Automated gas chromatographic assay for amlodipine in plasma and gingival crevicular fluid

This paper describes an automated capillary gas chromatographic method for the determination of amlodipine in plasma, and in sub-microlitre volumes of gingival crevicular fluid (GCF), in order to assess if amlodipine is present in GCF under conditions of gingival overgrowth, as has been shown for nifedipine, another dihydropyridine drug. Liquid-liquid extraction followed by derivatisation was employed to isolate amlodipine and render it suitable for gas chromatography. Amlodipine was analysed in plasma and GCF of four patients undergoing amlodipine therapy for cardiovascular disorders, three of whom had significant gingival overgrowth. Amlodipine was detected in the plasma of all patients and in massive concentrations in the GCF of those patients with overgrowth, 23- to 290-fold greater than in their plasma. Like nifedipine, amlodipine sequestration into GCF appears to be linked with gingival overgrowth.

The Effects of Amlodipine on Left Ventricular Mass and Diastolic Function in Concentric and Eccentric Left Ventricular Hypertrophy

BACKGROUND: The effects of the antihypertensive therapy with amlodipine (5-10 mg/day) on left ventricular mass and diastolic function were examined in 30 mild to moderate essential hypertensive patients who have left ventricular hypertrophy (LVH) and diastolic dysfunction. METHODS AND RESULTS: Each patient's left ventricular mass was measured, and left ventricular diastolic function was assessed by echocardiographic Doppler examination at entry, and at 3 and 6 months after the initiation of the treatment. Amlodipine reduced both blood pressure (from 164 +/- 14/104 +/- 6 mmHg to 134 +/- 9/83 +/- 4 mmHg) and left ventricular mass index (from 160 +/- 30 g/m(2) to 137 +/- 26 g/m(2)) significantly at 3 months and both parameters maintained at these levels for 6 months. When the patients were classified according to the type of the LVH, a significant regression in left ventricular mass index was seen only in the patients who had concentric LVH was a relative wall thickness >/=0.44 (n = 16), but not in the eccentric LVH group (n = 14), although both groups were not significantly different from each other regarding the basal hemodynamic parameters, baseline left ventricular mass index and the decrease in blood pressure in response to amlodipine treatment. The mitral inflow E/A ratio did not show any significant change in either group. CONCLUSIONS: Amlodipine produced significant regression in LVH only in the patients with concentric LVH, but not those with eccentric LVH, while it did not change the diastolic dysfunction. Therefore, the type of LVH seems to be an important feature in determining the effects of antihypertensive treatment on left ventricular mass index.

Electrophysiologic effects of amlodipine vs. diltiazem in patients with coronary artery disease and beta-blocking therapy

This study compares the electrophysiologic effects of amlodipine and diltiazem in patients with coronary artery disease concomitantly treated with background beta-blocking therapy. Thirty patients were included in an open-label parallel study in two phases. During phase 1, patients were screened and placed on maintenance atenolol therapy at 50 or 100 mg/day, while phase 2 consisted of right-sided catheterization and randomization of patients to either amlodipine (10 mg i.v.) or diltiazem (10 mg i.v.). Following treatment with amlodipine, no significant alteration in markers of electrophysiological activity was observed. Treatment with diltiazem resulted in a significant lengthening of sinus cycle length (SCL, p < 0.04), AH interval (p < 0.02), and Wenckebach CL (WCL, p < 0.001), and a trend towards an increase in sinus node recovery time (SNRT, p = 0.057). No effects were observed with regard to HV interval and corrected SNRT. The results of this study indicate that 10 mg intravenous amlodipine has no significant electrophysiological action on sinus or AV node function in patients receiving beta-blocker therapy with atenolol, suggesting that amlodipine can be added to beta-blockers to treat patients with myocardial ischemia and/or hypertension without any significant increase in the risk of bradyarrhythmias.

Amlodipine once a day in stable angina: double-blind crossover comparison with placebo

Although calcium antagonists form a mainstay of therapy in patients with angina pectoris, the currently available agents have significant limitations. Nifedipine, diltiazem, and verapamil are all high-clearance agents with significant hepatic extraction and rapid clearance, leading to limited and short-lived bioavailability necessitating frequent daily administration. In contrast, amlodipine, a dihydropyridine calcium antagonist, has a long half-life of 35-50 h (compared with 3 to 4 h elimination half-life of diltiazem, verapamil, and nifedipine). After oral doses, the relative bioavailability of amlodipine is high (64%) and absorption is smooth, with peak plasma levels being achieved 6-12 h postdose. Bioavailability is not affected by the consumption of food. In common with other dihydropyridine calcium antagonists, amlodipine is eliminated mainly by metabolism. None of the metabolites of amlodipine has significant calcium antagonist effects in humans. In contrast to verapamil or diltiazem, amlodipine has no effect on sinus or atrioventricular node and little or no effect on the resting heart rate. Amlodipine does not have any appreciable negative inotropic effect with the relevant clinical dose. Other clinical studies have shown amlodipine to be effective when used once-daily in chronic stable angina and vasospastic angina. Comparative studies indicate that the antianginal efficacy of amlodipine is comparable to the beta blocker nadolol and the benzothiazepine calcium antagonist diltiazem. Amlodipine has also been found to provide improved antianginal effects when combined to treatment with beta blockers and/or long-acting nitrates. Treatment with amlodipine either as monotherapy or combined with other antianginal therapy for up to 26 weeks shows that efficacy is maintained, with no evidence of tolerance.(ABSTRACT TRUNCATED AT 250 WORDS)

Pharmacodynamics of amlodipine: hemodynamic effects and antianginal efficacy after atrial pacing

The hemodynamic effects and antianginal efficacy of 10 mg amlodipine administered intravenously were assessed for 45 minutes in 18 subjects with stable angina pectoris. After amlodipine the heart rate was increased from 75 +/- 12 beats/min to 80 +/- 15 beats/min (p less than 0.05) for at least 15 minutes, with a decrease in systemic vascular resistance of 1091 +/- 205 to 815 +/- 390 dynes/sec/cm5 and a decrease in mean arterial pressure at 30 minutes from 99 +/- 11 to 91 +/- 10 (p less than 0.05). There was no change in dp/dt or dp/dt/IP or in cardiac output, wedge pressure, or pulmonary artery pressure. In the parallel placebo group (n = 8) there was no change in any of the hemodynamic parameters. Time to pacing-induced angina was increased in the treated group (n = 12) from 6 +/- 3.2 minutes before the dose to 8.2 +/- 4 minutes after the dose (p less than 0.01) compared to the control subjects who were given saline solution, in whom the time increased from 7 +/- 1.5 minutes before the dose to 7.5 +/- 2.2 minutes after the dose (n = 9). The double product at an equivalent pacing time to the initial onset of angina was reduced after therapy from 15,590 +/- 1490 to 14,100 +/- 1193 with a reduction in ST segment shift from 11.9 +/- 9.4 mm2 to 6.2 +/- 5.6 mm2 (p less than 0.05). Amlodipine after intravenous use has a vasodilator effect and also increases the anginal threshold without deleterious negative inotropic effects.