Duration of effects of isradipine during twice daily therapy in angina pectoris.

Isradipine, a 1,4 dihydropyridine calcium channel antagonist, is a potent coronary artery dilator that increases coronary blood flow with little effect on cardiac contractility. Isradipine is an approved antihypertensive agent, but its antianginal effects have not been well documented. In this placebo-controlled, double-blind, parallel-group design study we evaluated the duration of effects and safety of isradipine 10 mg bid in male patients with chronic stable angina pectoris. Seventy-two patients experiencing moderately severe angina between 3 and 7.5 minutes during a standard Bruce exercise test received placebo in a single-blind manner for 8-14 days. Sixty-one of these patients had reproducible treadmill exercise test results on three consecutive occasions and underwent further exercise tests at 3, 8, and 12 hours after a placebo period. Patients were then randomized (double blind) to either placebo or isradipine 10 mg bid for 2 weeks. Symptom-limited exercise tests were repeated predose and at 3, 8, and 12 hours after the 0800 hour dose dosing. Exercise duration increased significantly from baseline (last qualifying test during the single-blind placebo therapy, i.e., 0800 hours predose at visit 4) in the isradipine group compared to the placebo group prior to the administration of the 0800 hour dose (i.e., 12 hours after the 2000 hour dose) by 51 vs. 18 seconds, p = 0.04; and after the administration of the 0800 hour dose at 3 hours by 78 vs. 29 seconds, p = 0.005; and at 8 hours by 54 vs. 18 seconds, p = 0.04. Similarly, statistical significance was achieved when exercise data were analyzed using visit 4 (single-blind placebo therapy) corresponding time points as baseline. At 12 hours after the 0800 hour dose, exercise tolerance did not increase significantly after isradipine compared to placebo. Time to 1-mm ST-segment depression increased significantly after isradipine at 3 hours post 0800 hour dose compared to placebo (87 vs. 7 seconds, p < 0.01) but not at the 0, 8, or 12-hour postdose time points, regardless of which baseline was used. Isradipine therapy did not affect the rate-pressure double product. A significant correlation between the mean increase in total exercise time and mean plasma isradipine concentration was also present (p = 0.0295). During double-blind treatment, drug-related adverse events were experienced by four patients in the isradipine group and two patients in the placebo group. None of the patients experienced ischemic complications during the study.(ABSTRACT TRUNCATED AT 400 WORDS)

Lack of pharmacologic tolerance and rebound angina pectoris during twice-daily therapy with isosorbide-5-mononitrate.

OBJECTIVE: To determine whether isosorbide-5-mononitrate (IS-5-MN), an active metabolite of isosorbide dinitrate, when given twice daily (in the morning and 7 hours later), prevents development of tolerance and reduction in exercise performance or is associated with a rebound increase in anginal attacks in patients with stable angina pectoris. DESIGN: Multicenter, placebo-controlled, parallel-group, double-blind, randomized study. SETTING: Four university teaching hospitals and five private cardiology outpatient clinics. PATIENTS: 116 patients with stable exertional angina who stopped treadmill exercise because of angina pectoris. INTERVENTION: After stopping all antianginal drugs with the exception of beta-blockers, patients received single-blind placebo for 1 week followed by either 20 mg of IS-5-MN (n = 60 patients) or placebo (n = 62 patients) twice daily at 0800 hours and 1500 hours for 2 weeks. MEASUREMENTS: Serial symptom-limited exercise tests and patients' diaries recording activity and date, time, and severity of anginal attacks. RESULTS: Compared with placebo recipients, patients receiving IS-5-MN walked significantly longer at 2, 5, and 7 hours after the 0800-hour dose (P < 0.01) and at 2 and 5 hours after the 1500-hour dose (P < 0.01). Before the morning (0800-hour) dose, exercise duration increased by 0.53 minutes in placebo recipients and by 0.85 minutes in those receiving IS-5-MN therapy (P = 0.10). Neither nocturnal nor early-morning anginal attacks increased during IS-5-MN therapy compared with placebo. Headaches occurred in 19 (32%) patients in the IS-5-MN group and in 9 (15%) patients in the placebo group but necessitated discontinuation of treatment in only 2 (3%) patients in the IS-5-MN group. CONCLUSION: Isosorbide-5-mononitrate, 20 mg twice daily given 7 hours apart, was well tolerated and improved exercise performance for 7 hours after the morning dose and for 5 hours after the afternoon dose without evidence of development of pharmacologic tolerance. No rebound increase in anginal attacks was found.

A multicenter double-blind study of the efficacy and safety of once and twice daily dilevalol compared to propranolol.

Dilevalol, the R,R isomer of labetalol, is a non-selective beta-adrenergic blocking drug with vasodilator properties which differ from those of labetalol in that they are attributable to beta-2 agonism rather than alpha-1 blockade. This multicenter, double-blind, randomized study compares the antihypertensive efficacy and safety of dilevalol with propranolol and, in addition, compares the efficacy of dilevalol when given once daily with twice daily. Caucasian patients with mild and moderate essential uncomplicated hypertension were divided into three treatment groups and received either propranolol twice daily (N = 59), dilevalol twice daily (N = 60), or dilevalol once daily (N = 53). Patients were given increasing doses of these medications over a 2 to 10 week period to achieve a supine diastolic blood pressure (SuDBP) of less than 90 mm Hg. The three regimens were equally effective in lowering supine blood pressure (dilevalol daily and twice daily reduced SuDBP by 14 Hg and propranolol by 13 mm Hg). Patients with at least a 5 mm Hg reduction in SuDBP then entered a two month maintenance phase. Dilevalol, whether given once (N = 40) or twice daily (N = 55) maintained the supine systolic blood pressure more effectively (dilevalol daily--15 mm Hg, twice daily--13 mm Hg, P less than .05) than propranolol (N = 53, 11 mm Hg) and dilevalol given once daily maintained diastolic blood pressure more effectively than propranolol (17 mm Hg v 14 mm Hg, P less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Dilevalol compared with propranolol and placebo for systemic hypertension.

Dilevalol is a new antihypertensive agent that is both a vasodilator, through its beta 2-agonist action, and a nonselective beta antagonist. Two multicenter, double-blind studies were performed: study 1 compared dilevalol administered once-daily with either dilevalol or propranolol every 12 hours; study 2 compared dilevalol administered once daily with placebo. Both studies had a placebo run-in period to establish that the baseline supine diastolic blood pressures were consistent in the mild to moderate severity range (95 to 115 mm Hg) at 2 consecutive visits for study 1 and in the mild severity range (95 to 105 mm Hg) in study 2. Patients then were randomized to the double-blind titration phase, during which doses were titrated over a 9-week period to achieve a supine diastolic blood pressure of less than 90 mm Hg and a decrease from baseline of greater than or equal to 10 mm Hg. Patients were then maintained on a fixed dose for 2 months (study 1) or for 1 month (study 2). Dilevalol given once daily was as effective in reducing supine diastolic blood pressure as dilevalol every 12 hours and propranolol every 12 hours (study 1) and was superior to placebo (p less than 0.001) (study 2). In both studies, dilevalol given once daily was effective and well tolerated. The side-effect profile of dilevalol was similar to that of placebo and different from that of propranolol. Treatment with dilevalol resulted in significantly less fatigue (p less than 0.05), bradycardia (less than 50 beats/minute) and mental depression than with propranolol, but significantly (p less than 0.05) more diarrhea/loose stools.(ABSTRACT TRUNCATED AT 250 WORDS)

Multicenter comparison of dilevalol to placebo in patients with mild hypertension.

The antihypertensive effects of oral dilevalol, a beta-blocking agent with vasodialating properties were compared with placebo in 128 mildly hypertensive patients (supine diastolic blood pressure 95 to 105 mm Hg) in a multicenter, double-blind, parallel group study. Following a 4-week placebo phase, 63 patients were randomly assigned to receive dilevalol and 65 to receive placebo. A titration phase followed during which the dose of dilevalol was increased every other week from 100 mg to 800 mg to achieve a supine diastolic blood pressure (SDBP) less than 90 mm Hg and decreased by 10 mm Hg or more from baseline. A matching number of placebo capsules for each dose level of dilevalol was dispensed for blinding purposes. Patients who had at least a 5 mm Hg reduction in SDBP entered a 1-month maintenance phase. Blood pressure and heart rate were measured weekly 20 to 24 hours after a dose. This study demonstrated that the minimally effective dose of dilevalol was 100 mg, which was shown to result in a significantly (P less than or equal to 0.05) greater reduction in systolic BP. A once-daily dose of 200 mg was superior to placebo in both systolic and diastolic BP effects (P less than 0.001 and less than 0.001, respectively), and this superiority was seen again at both the end of titration and the end of the study. The BP reduction was accompanied by a small (5 bpm) decrease in heart rate. The side effect profile of dilevalol was not different from placebo. Dilevalol appears to have no adverse effect on plasma lipids.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of labetalol and prazosin in hypertensive patients using automated ambulatory monitoring.

The differential effects of prazosin and labetalol on blood pressure and heart rate in the clinic and during daily activity were measured in a double-blind study utilizing automatic ambulatory monitors. One hundred five patients with essential hypertension (sitting diastolic blood pressure equal to 101 mm Hg) were randomly assigned to receive prazosin (n = 52) or labetalol (n = 53). Sixty-eight percent of labetalol-treated patients and 50 percent of prazosin-treated patients achieved blood pressure control during clinic visits (sitting diastolic blood pressure less than 90 mm Hg) and were subsequently monitored for 12 hours of normal daily activities. Ambulatory monitoring revealed labetalol-treated patients to have significantly greater decreases in systolic and diastolic blood pressures during daily activity than prazosin-treated patients. Heart rate and rate-pressure product were significantly reduced in the labetalol group but not in the prazosin group. It is concluded that the potential benefits of dual adrenergic blockade, not readily apparent in the non-stressful clinic environment, become more evident during the course of daily activities.

Isolated systolic hypertension in the elderly. A placebo-controlled, dose-response evaluation of chlorthalidone.

One hundred seventy-one patients, 60 years of age or older with isolated systolic hypertension, were randomly assigned to receive chlorthalidone 12.5, 25.0, or 50.0 mg or placebo once daily for 12 weeks. The majority of the patients receiving chlorthalidone 12.5 mg achieved therapeutic success with no clinically significant biochemical changes or side effects. The 50.0-mg dose level enhanced efficacy only minimally over the 25.0-mg dose level. Drug-related side effects were significantly more prevalent in the chlorthalidone 50.0-mg group than in the placebo group. The data suggest that most elderly patients with isolated systolic hypertension, regardless of the severity, could be treated effectively and safely with chlorthalidone 12.5 mg per day.

Limitations of continuous ambulatory electrocardiogram monitoring for detecting coronary artery disease.

To assess the value of continuous ambulatory electrocardiogram (ECG) monitoring for detecting coronary artery disease in symptomatic patients, we evaluated 70 patients with chest pain and normal resting ECGs prospectively by calibrated ambulatory monitoring, graded treadmill exercise, and selective coronary cineangiography. Ischemic-type ST-wave changes were detected by monitoring in 24 of the 39 patients with coronary artery disease (62% sensitivity). Twenty-six of the 39 patients had a positive treadmill (67% sensitivity). Of the 31 patients without coronary disease on angiography, 19 had negative monitoring studies (61% specificity). The treadmill was negative in 23 of these 31 patients (75% specificity). When the results of both tests were combined, 85% of the cases of coronary artery disease were detected, but only 52% of the patients without disease had negative studies. We conclude that continuous ambulatory monitoring is of limited value for detecting or excluding coronary artery disease in symptomatic patients with normal resting ECGs.

Left ventricular performance in patients with left ventricular hypertrophy caused by systemic arterial hypertension.

To assess the adaptation of the left ventricle to a chronic pressure overload we used echocardiography to study 18 patients with left ventricular hypertrophy caused by systemic arterial hypertension. Increased values for either posterior wall or interventricular septal thickness or both confirmed the presence of left ventricular hypertrophy in all patients and an increase in the average wall thickness to radius ratio was consistent with the development of concentric hypertrophy. No patient had clinical evidence of ischaemic heart disease. Ejection phase indices of left ventricular performance (mean Vcf, fractional per cent of shortening, normalised posterior wall velocity, and ejection fraction) were within the normal range in the basal state in 16 of the 18 patients. The hypothesis is advanced that patients with concentric left ventricular hypertrophy resulting from systemic arterial hypertension usually have normal left ventricular performance in the basal state because values for wall stress remain within the normal range. We conclude that the hypertrophic response to a chronic increase in systemic arterial pressure does not per se result in depression of the basal inotropic state of the left ventricle.