Comparative efficacy of nicardipine hydrochloride and atenolol in the treatment of chronic stable angina

Atenolol or nicardipine alone is as efficacious in stable angina as their combination: a double blind randomised trial

BACKGROUND

Beta blockers and calcium antagonists are widely used in the management of angina pectoris in the belief that the combination is more efficacious than either drug alone.

METHODS

This double blind randomised crossover placebo controlled study compares the effects of nicardipine, atenolol and their combination in 30 patients with chronic stable angina. Each treatment period lasted 6 weeks with dose titration after 3 weeks. Symptom limited treadmill exercise testing and radionuclide ventriculography at rest was carried out at the end of each treatment period.

RESULTS

Total exercise duration and time to 1-mm ST-segment depression was significantly prolonged by nicardipine and atenolol when compared to placebo, the combination offered no additional benefit. Time to onset of angina was significantly prolonged by nicardipine and the combination but not by atenolol. Indices of left ventricular function were not significantly affected by any treatment other than an increase in left ventricular end diastolic volume on atenolol and the combination.

CONCLUSIONS

Nicardipine and atenolol are equally effective in prolonging exercise duration and time to onset of ischemia in patients with chronic stable angina while the combination appeared to offer no additional benefit. Nicardipine prolonged the time to onset of angina significantly; again there was no further improvement with the combination. Neither drug appears to have an important effect on the parameters of diastolic function studied in patients with chronic stable angina.

Nicardipine, a new calcium channel blocker: role for vascular selectivity

Calcium channel blockers are important drugs for the treatment of chronic stable angina. However, negative inotropic and dromotropic effects may limit their usefulness in patients with atrioventricular conduction abnormalities or left ventricular dysfunction. A new generation of calcium channel blockers will soon be available that have a more vascular selective action than currently available agents. Of the new agents, nicardipine has been most extensively studied. In experimental studies, nicardipine is more specific for vascular smooth muscle than for cardiac smooth muscle and for coronary than peripheral vasculature. In controlled trials, nicardipine exhibited efficacy and safety that was comparable to older calcium blockers or beta blockers. However, nicardipine was associated with minimal negative inotropic or dromotropic effects even in patients with existing left ventricular dysfunction. Thus, nicardipine may have an advantage over existing calcium channel blockers, especially in patients with underlying cardiac disease.

Electrophysiologic evaluation of intravenous nicardipine in man

The acute electrophysiological effects of intravenous nicardipine (0.014 mg/kg per min for 5 minutes) were studied in 12 subjects with estimated normal sinus node functions and atrioventricular conduction parameters. The most important effects were sinus cycle length shortening, increase of corrected sinus node recovery time and reduction of effective and functional refractory period of the atrioventricular node. Sinuatrial conduction time, atrial refractory periods, intranodal conduction, bundle branch refractoriness and ventricular refractoriness were unchanged. Systolic and diastolic blood pressure was reduced. The clinical implications of these properties of the drug are discussed and compared with those of verapamil, diltiazem and nifedipine.

Therapy for angina pectoris: comparison of nicardipine with other antianginal agents

Nicardipine is a new dihydropyridine calcium channel blocking drug with actions that suggest considerable usefulness as an agent for chronic stable angina. Hemodynamic studies in patients with coronary artery disease confirm major coronary vasodilator actions, perhaps even exceeding its considerable systemic vasodilator properties with little or no negative inotropic effect. Three recent controlled clinical trials that used nicardipine alone suggest approximately 20% to 30% increase in exercise time, and at least that much decrease in anginal episodes and sublingual nitroglycerin consumption when compared with placebo in doses of 90 to 120 mg daily. Five trials comparing nicardipine with other calcium channel blockers, and three with beta blockers, suggest equivalent efficacy, including decrease in angina and increase in exercise time. Adverse effects of nicardipine generally relate to its potent vasodilatory capability and are usually minor. Side effects are frequent at the beginning of many trials, usually do not cause undue withdrawals, and are quite rare after 6 to 12 months on the drug in most studies.