Isradipine in essential hypertension: the Belgian General Practitioners' Study

Amlodipine, felodipine, and isradipine in the treatment of Chinese patients with mild-to-moderate hypertension

Optimal treatment of hypertension requires the use of effective antihypertensive drugs. Calcium channel blockers are widely used in the treatment of hypertension and appear to be particularly efficacious in ethnic Chinese patients. The aim of this open-label study was to prospectively investigate the efficacy and tolerability of three dihydropyridine calcium channel blockers in sequence, using the same protocol for each. After 2 weeks of placebo treatment, 73 males and 45 females (mean age, 45 +/- 10 years; mean weight, 67 +/- 10 kg) with essential hypertension (diastolic blood pressure, 95 to 115 mm Hg) were treated with amlodipine (n = 41), felodipine (n = 38), or isradipine (n = 39) for 8 weeks, with dose titration after 4 weeks. Mean seated systolic and diastolic blood pressure decreased by 23/17, 30/17, and 20/15 mm Hg after 8 weeks of treatment with amlodipine, felodipine, and isradipine, respectively. These reductions were all statistically significant. Blood pressure was controlled (defined as diastolic pressure < 90 mm Hg at the final visit or a decrease from baseline of > or = 10 mm Hg) in 85%, 74%, and 74% of patients receiving amlodipine, felodipine, and isradipine, respectively. There were no significant changes in heart rate, plasma lipid levels, or serum biochemistry markers with any of the three treatments. No serious adverse events occurred, but mild adverse effects, including headaches, flushing, tachycardia, dizziness, and edema, were reported; 1 (2%), 6 (16%), and 5 (13%) patients receiving amlodipine, felodipine, and isradipine, respectively, withdrew from the study (P < 0.05). The results of this study indicate that all three drugs are highly effective in lowering blood pressure and are well tolerated in Chinese patients with mild-to-moderate hypertension.

At equipotent doses, isradipine is better tolerated than amlodipine in patients with mild-to-moderate hypertension: a double-blind, randomized, parallel-group study

1. The objective of this double-blind parallel-group study was to compare the tolerability of isradipine and amlodipine, specifically, the side-effects known to be related to the use of dihydropyridine calcium antagonists. 2. A total of 205 patients with mild-to-moderate essential hypertension were randomized to receive either the sustained-release (SRO) formulation of isradipine (n = 103) or amlodipine (n = 102), both at dosages of 5 mg once daily. Blood pressure measurements were taken at the end of the dosing interval to assess the antihypertensive efficacy of the two drugs. 3. Adverse reactions were assessed in two ways: a) spontaneously reported adverse events were recorded and investigated in depth for severity, duration, relation to the study drug, and outcome; b) a questionnaire was used to elicit specific adverse reactions known to be related to the use of dihydropyridine calcium antagonists which were evaluated for severity, duration, relation to the study drug, and outcome. 4. After 6 weeks of active treatment, both isradipine and amlodipine reduced mean sitting systolic/diastolic blood pressure: from 165.1/100.1 to 145.2/89.7 mm Hg with isradipine; and from 164.1/100.6 to 145.7/90.5 mm Hg with amlodipine. There was no difference in antihypertensive effect between isradipine and amlodipine (95% CI: -3.73 to 4.73 and -1.89 to 3.49 for differences in systolic and diastolic blood pressure, respectively). 5. The number of patients spontaneously reporting adverse events was significantly higher (P = 0.02; 95% CI: 3.1 to 26.7%) with amlodipine (33.3%) than with isradipine (18.4%).(ABSTRACT TRUNCATED AT 250 WORDS)

Isradipine and the coronary circulation

Isradipine has been shown to be an effective vasodilator in different vascular beds. Experimental evidence suggests that isradipine is a potent coronary vasodilator, and this is supported by clinical studies in both cardiology and cardiac surgery. Furthermore, in these studies, coronary vasodilation was not accompanied by evidence of any significant effect on cardiac contractility or conduction. It can be concluded that the cardiac effects of isradipine will ultimately prove to be beneficial in patients undergoing myocardial revascularization.

Dose titration study of isradipine in Chinese patients with mild to moderate essential hypertension

In order to assess the effective dose, tolerability, and safety of isradipine as a monotherapeutic antihypertensive agent for Chinese patients in Taiwan, an open trial was carried out. This study consisted of a 2-week, placebo, run-in period and an 8-week active treatment period, starting with isradipine 1.25 mg twice daily (bid) for the first 4 weeks, followed by 2.5 mg bid if the blood pressure was not normalized (diastole < 90 mmHg). One hundred and one patients (M/F = 48:53) were valid for efficacy analysis. Their age ranged from 30 to 64 years (mean +/- SD, 52 +/- 8). The blood pressure before active treatment was 160 +/- 2/104 +/- 1 mmHg. At the end of treatment period I (week 4), 12-14 hours after the last dose, 38 (37.6%) patients were normalized and 47 (46.5%) subjects responded (diastolic blood pressure reduction > or = 10 mmHg). At week 8, 68 (67.3%) patients were normalized and 79 (78.2%) subjects responded. Isradipine reduced both systolic and diastolic blood pressures within 2 weeks of treatment. There were no significant differences in blood pressure reduction between both genders and among age groups. Safety analysis showed two subjects with severe flushing, dizziness, and palpitation who used the dose of 1.25 mg bid. They withdrew from the study. The adverse reactions of other patients were transient, mild, and tolerable. Most of the side effects were related to vasodilatation, but edema was not found. There was no change in body weight or heart rate, nor any atrioventricular conduction disturbances.(ABSTRACT TRUNCATED AT 250 WORDS)

Isradipine--another calcium-channel blocker for the treatment of hypertension and angina

OBJECTIVE

To review the pharmacology, pharmacokinetic disposition, dose recommendations, adverse effects, drug interactions, and efficacy of isradipine in patients with hypertension or ischemic heart disease.

DATA SOURCES

Data from scientific literature were extracted, evaluated, and summarized for presentation. A MEDLINE search was conducted using the following indexing terms: isradipine, calcium-channel blockers, hypertension, and angina pectoris. Experiences from studies evaluating isradipine reported in the form of articles, abstracts, or proceedings involving patients or healthy subjects were considered for inclusion.

STUDY SELECTION

Special consideration was given to clinical studies that had been designed in a blind, randomized fashion. Studies that compared the effectiveness and safety of isradipine with another antihypertensive or antianginal agent or placebo were included.

DATA EXTRACTION

Data from human studies published in the English language were evaluated. Trials were evaluated according to sample size, design, and adequacy of description of therapeutic response.

DATA SYNTHESIS

Isradipine is a new dihydropyridine calcium-channel blocker that appears to exert less negative inotropic activity than nifedipine and to selectively inhibit sinoatrial conduction. Pharmacokinetic parameters are quite variable and considerably more work is needed to better describe the kinetic disposition of isradipine. Antihypertensive efficacy has been demonstrated extensively in a number of short-term trials. Antianginal efficacy also has been observed in a few short-term trials and is comparable to that of isosorbide dinitrate and nifedipine. Extensive experience with isradipine is minimal and no clear-cut advantages over existing compounds have been noted thus far.

CONCLUSIONS

The place of isradipine in the therapy of hypertension and myocardial ischemia is unclear and its routine use cannot yet be recommended based solely on clinical grounds.

Isradipine

Isradipine is a potent dihydropyridine calcium channel blocker. It is highly selective for vascular smooth muscle, with very few negative inotropic or chronotropic effects. It may have minor depressant effects on the sinoatrial node, hence reducing the incidence of reflex tachycardia. The drug is extensively metabolized in the liver, with several pharmacologically inactive metabolites. As the elimination half-life is about 9 h the drug is usually given twice daily, but a once-daily modified release form is under investigation. Isradipine is effective monotherapy in essential hypertension, and has been successfully combined with pindolol and captopril. On the basis of more limited evidence it also appears to be beneficial in stable angina and in congestive cardiac failure. A trial is also under way to assess its antiatherogenic properties. Adverse effects are those predicted for a vasodilator calcium antagonist, and may be less frequent than for equivalent doses of nifedipine. This needs to be confirmed by more extensive clinical experience. Overall, isradipine can be considered favourably in essential hypertensives where a calcium channel blocker is indicated, particularly if it is desirable to avoid myocardial depression or to minimize reflex tachycardia. Its role in other cardiovascular disease awaits further evaluation.