Safety, efficacy and pharmacokinetics of nicardipine in elderly hypertensive patients

Lack of effect of isradipine on cyclosporin pharmacokinetics

The influence of isradipine as a long acting form (IcazR LP 5 mg) on cyclosporin pharmacokinetics was studied in six hypertensive renal transplant patients (mean age 37 yrs; mean body weight 62 kg). These patients received a mean daily cyclosporin dose of 307 mg in two equal intakes. Isradipine was orally administered once a day at a dose of 5 mg before the morning cyclosporin intake. Cyclosporin kinetics was assessed over a 0-12-h period, the day before (D-1) and 13 days (D+13) after isradipine treatment. Whole blood concentrations of cyclosporin were determined by radioimmunoassay (RIA) using the SandimmuneR-RIA kit (specific and non-specific monoclonal antibodies). Area under the blood concentration-time curve (AUC), the maximum blood concentration (Cmax) and the time to reach Cmax (Tmax) on D-1 and D+13 were not significantly different whatever the specificity of the RIA method. For example, the mean AUC +/- sd values were 5,247 +/- 2,255 (D-1) vs 5,317 +/- 1,675 (D+13) microgram.1(-1).h for the specific and 20,905 +/- 8,317 vs 19,327 +/- 5,758 microgram.1(-1).h for the non-specific determinations. Therefore, the pharmacokinetics of cyclosporin is not influenced by co-administration of isradipine at a therapeutic dosage. Moreover, the clinical results show that isradipine treatment was effective after 13 days administration (mean systolic blood pressure 132 vs 158 mm Hg, P < 0.05 and mean diastolic blood pressure 77 vs 93 mm Hg, P < 0.05 in supine position), and well tolerated throughout the study.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of Org 7797 on early, late and inducible arrhythmias following coronary artery occlusion in rats and dogs

1. The class Ic steroidal antiarrhythmic agent, Org 7797, was compared with two other Ic agents, flecainide and propafenone for intravenous activity against ischaemia-related cardiac arrhythmias and for electrophysiological actions in vivo. In addition the haemodynamic effects of Org 7797 were assessed in greyhounds. 2. Org 7797 (0.5 mg kg-1) significantly reduced the expected incidence of early ischaemia-induced ventricular fibrillation (VF) in rats and greyhound dogs and at doses of 0.5-1.0 mg kg-1 antagonized reperfusion-induced arrhythmias. Comparative studies in rats showed Org 7797 to be 2-4 times more potent than flecainide or propafenone. 3. Org 7797 (0.5 mg kg-1) slowed intracardiac conduction in anaesthetized beagles and again was at least 2-4 times more potent than flecainide or propafenone. 4. Org 7797 (0.5 and 2.0 mg kg-1), flecainide (1.0 and 2.0 mg kg-1) or propafenone (0.5 and 2.0 mg kg-1), did not significantly prevent induction of tachyarrhythmias (VT) in dogs with 5-6 day old myocardial infarcts although all 3 drugs appeared to prevent induced VF. All 3 drugs (notably flecainide) did however reduce the VT rate. 5. All 3 drugs (1-2 mg kg-1) suppressed spontaneous tachyarrhythmias in conscious beagle dogs with 1-2 day old infarcts. Propafenone was the least effective. 6. In an antifibrillatory dose (0.5 mg kg-1), the major haemodynamic effect of Org 7797 was a 10% increase in peripheral vascular resistance. Stroke volume, cardiac output and coronary blood flow were unchanged. In therapeutic doses, Org 7797 was also less negatively chronotropic than flecainide.7. It was concluded that Org 7797 is a potent antifibrillatory agent which is haemodynamically well tolerated. Higher doses are required to suppress late ischaemia-induced tachyarrhythmias which suggest that its antifibrillatory effects are the consequence of an action other than, or in addition to, sodium channel block.

Comparison of the electrophysiological effects of Org 7797, disopyramide, mexiletine and propafenone in anaesthetized dogs with myocardial infarcts

1. The electrophysiological effects of intravenously administered Org 7797 were compared with those of disopyramide (class Ia), mexiletine (Ib) and propafenone (Ic) in anaesthetized dogs with 5-6 day-old left ventricular myocardial infarcts. 2. Org 7797 (0.5 mg kg-1) slowed conduction at all levels of the myocardium as shown by increases in St-A, AH, HV and QRS intervals, very modestly prolonged atrial and ventricular refractory periods and slightly shortened ventricular repolarization. Sinus node recovery time was increased whilst the RR interval was unchanged. A higher dose (2 mg kg-1) prolonged RR and rendered 5 out of 8 dogs unable to follow an atrial pacing stimulus of mean cycle length 322 ms. 3. Electrophysiological changes induced by propafenone (2 mg kg-1) were qualitatively similar to those of Org 7797 (0.5 mg kg-1). 4. Electrophysiological changes induced by mexiletine (2 mg kg-1) were small or insignificant. The most noticeable effect was a modest increase in the St-A interval and a slight shortening of ventricular repolarization. A higher dose (8 mg kg-1) additionally slowed conduction in the His-Purkinje system and in the ventricular myocardium. 5. Disopyramide (2 and 5 mg kg-1) prolonged all cardiac intervals including JTc, QTc and QT during pacing and prolonged cardiac refractory periods. 6. It was concluded that the electrophysiological profile of Org 7797 is more like that of the Ic agent propafenone than that of the class Ia and Ib drugs, disopyramide and mexiletine.

New therapeutic modalities in hypertension: focus on a new calcium antagonist-nicardipine

A new generation of dihydropyridine calcium antagonists which are related structurally to nifedipine is undergoing clinical investigation. Among these newer agents. nicardipine and nimodipine have become available for clinical use. In controlled trials, nicardipine is superior to placebo and equal to other antihypertensive agents for the treatment of systemic hypertension. Nicardipine is associated with a low incidence of adverse effects that are related primarily to its peripheral vasodilatory actions. In addition, nicardipine appears to have little if any negative effects on myocardial contractility or conduction.

Nicardipine in the elderly hypertensive: a review of experience in the United Kingdom

Clinical trials in the United Kingdom have supported those conducted elsewhere in showing that nicardipine is an effective antihypertensive drug in the elderly, with a tendency to produce lower diastolic blood pressure than in younger patients. Side effects are mainly related to vasodilation and are no more common than in younger patients. Nicardipine does not cause any chronic activation of the sympathetic nervous system or the renin-angiotensin system.

Nicardipine monotherapy in ambulatory elderly patients with hypertension

The antihypertensive effect of nicardipine was evaluated in 89 ambulatory elderly patients with hypertension through a multicenter trial enrolling patients over the age of 65 years. After a baseline period during which they received placebo, subjects were randomized by an unbalanced assignment to a double-blind comparison of nicardipine (n = 57) and placebo (n = 32). The initial dose of nicardipine was 20 mg every 8 hours, which was then increased to 30 mg if needed. Blood pressure and heart rate were measured 1 and 8 hours after doses at each visit with subjects in both the supine and standing positions. Seventy-six per cent of patients who received nicardipine and 55% who received placebo responded (p less than 0.05). During standing, blood pressure did not decrease significantly from supine levels in either group, but a small, transient increase in heart rate occurred with nicardipine. Adverse reactions (apart from failure to respond) occurred in 8% of those who received nicardipine and 3% who received placebo. Three patients were withdrawn: two for symptoms, nausea, or flushing and one for transient and asymptomatic abnormalities on ECG. Nicardipine is effective and safe as monotherapy in elderly patients with hypertension, causing greater reduction in systolic than in diastolic pressure, but without orthostatic hypotension.

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.