Comparison of the antianginal effectiveness of nifedipine, verapamil, and isosorbide dinitrate in patients receiving propranolol: a double-blind study

Anti-anginal efficacy of a controlled-release formulation of isosorbide-5-mononitrate once daily in angina patients on chronic beta-blockade

The anti-anginal effect of a controlled-release (Durules) formulation of isosorbide-5-mononitrate (5-ISMN) 60 mg, Imdur, once daily was evaluated in a randomised double-blind, placebo-controlled, crossover study with a placebo run-in period. Each period lasted for 2 weeks. A total of 70 patients (58 men and 12 women) with stable exertional angina pectoris on beta-blockade, mean age 59 years (range 39-71), were included. Exercise testing was performed on a bicycle ergometer 3 hours after the dose at the end of each period. Anginal attacks and intake of sublingual nitroglycerin tablets were noted. Imdur in combination with a beta-blocker significantly increased the total exercise capacity, the time and total work until the onset of chest pain and at 1 mm ST-depression compared with beta-blockade alone. The attack rate and the nitroglycerin consumption were significantly decreased. Headache was the only significant side-effect. In conclusion, the addition of Imdur once daily to beta-blockade significantly increased the anti-anginal effect.

Efficacy of different forms of nitrates in angina pectoris

Nitroglycerin has maintained its position in the treatment of angina pectoris for more than a century. Efficacy of oral nitrates has been established and compares well with that of other anti-anginal drugs. New delivery systems are being developed for sustained systemic nitrate action. Beneficial action of nitrates in congestive heart failure and their crucial role in unstable angina and acute myocardial infarction has further widened their therapeutic use. A plausible hypothesis of the mechanism of nitrate-induced vasodilation has been presented, involving production of nitrosothiols and activation of guanylate cyclase in the vascular smooth muscle. Recent developments suggest that the rate degradation of nitrates and formation of nitrosothiols in the vascular smooth muscle are linked, offering an explanation to the relatively rapidly developing, but partial vascular tolerance during high-dose nitrate therapy.

Antianginal efficacy over 24 hours and exercise hemodynamic effects of once daily sustained-release 300 mg diltiazem and 240 mg verapamil in stable angina pectoris

The antianginal efficacy of 240 mg sustained release verapamil once daily doses and 300 mg diltiazem was studied in 20 normotensive patients with chronic stable angina pectoris, using a randomized, double-blind crossover design. Patients received a blinded therapy of verapamil placebo and diltiazem placebo for six weeks than only sustained-release diltiazem (SRD) for a long-term phase of three weeks, after a two-week placebo baseline period. Symptom-limited bicycle exercise was longer with the verapamil (510+/-129.9 s) and diltiazem (540+/-124.6 s) than with placebo at baseline (396+/-152.2 s, P<0.005). Verapamil and diltiazem reduced the weekly rate of anginal attacks from 5.1+/-8.6 during placebo to 4.4+/-4.1 with verapamil and 1.9+/-3.2 with diltiazem (P<0.05). The antianginal effects of the two agents are probably mediated by reduction of myocardial oxygen demand at submaximal exercise. In addition, diltiazem appears to provide more symptomatic relief and reduces the weekly number of anginal attacks significantly more than verapamil. Therefore its once-daily administration simplifies the treatment schedule and should improve patients' compliance.

Safety and compatibility of betaxolol hydrochloride combined with diltiazem or nifedipine therapy in stable angina pectoris

Compared with placebo, adding betaxolol 20 mg every day to nifedipine (up to 60 mg/day in divided doses) or diltiazem (up to 360 mg/day in divided doses) for a 3-week treatment period in 135 patients with stable angina pectoris significantly (p < 0.05) lengthened the time to onset of moderate angina during exercise tolerance tests at all treatment time points. The median increases in the time to onset of moderate angina at the final exercise tolerance test (end point) compared with baseline were 1.08 and 0.53 minutes for betaxolol and placebo groups, respectively (p = 0.002, betaxolol and placebo groups, respectively (p = 0.002, betaxolol vs placebo). The time to onset of 1 mm ST-segment depression increased significantly (p < 0.05) with betaxolol compared with placebo at all but 1 treatment time point (median increase [p = 0.001] 1.77 and 0.37 minutes, respectively, at end point). Duration of exercise also was increased significantly (p < 0.05) after the third week of treatment and at end point (median 0.62 and 0.50 minutes, respectively; p = 0.03). Generally comparable results were found within the diltiazem (n = 128) and nifedipine (n = 25) subgroups, although the nifedipine group was too small to detect statistically significant differences between betaxolol and placebo treatment. Resting systolic blood pressure, heart rate and the rate-pressure product, measured both when angina occurred and at the end of exercise, also were influenced significantly (p < 0.05) by the betaxolol addition. The only serious adverse effect associated with betaxolol treatment was syncope, seen in 2 patients.

Effect of KRN2391, a novel vasodilator, on various experimental anginal models in rats

The antianginal effect of KRN2391, N-cyano-N'-(2-nitroxyethyl)-3-pyridinecarboximidamide monomethanesulfonate, on various anginal models in rats was compared with those of nifedipine and nicorandil. Angina pectoris was induced by methacholine or isoproterenol, and the change in the ST-segments in the electrocardiogram (ECG) was used as the parameter to indicate angina pectoris. The intracoronary administration of methacholine (3 micrograms) produced an elevation in the ST-segment of the ECG. This ST-elevation was inhibited by the intravenous administration of KRN2391 (30 and 100 micrograms/kg), nifedipine (100 and 300 micrograms/kg) and nicorandil (1000 and 3000 micrograms/kg). The administration of isoproterenol (10 micrograms/kg/min, i.v.) produced a depression of the ST-segment of the ECG. The intravenous administration of KRN2391 (100 micrograms/kg), nifedipine (100 micrograms/kg) and nicorandil (3000 micrograms/kg) inhibited the ECG changes induced by isoproterenol. These results suggest that KRN2391 exerts a potent protective effect on angina pectoris models compared with nifedipine and nicorandil. KRN2391 appears to be useful as an antianginal drug.

Enhanced effectiveness of combined sustained-release forms of isosorbide dinitrate and diltiazem for stable angina pectoris

In 14 patients with documented coronary artery disease, the extent and duration of acute anti-ischemic, antianginal and hemodynamic effects of monotherapies with 120 mg of sustained-release isosorbide dinitrate and diltiazem were compared; their combined therapy administered once daily in the morning with diltiazem given again in the evening were also compared according to a randomized, double-blind, crossover, placebo-controlled protocol including exercise testing for assessment of ST-segment depression (ST decreases) at an identical work load, exercise capacity and determination of plasma concentrations of both substances. Comparison of individual substances revealed more marked and sustained effects of isosorbide dinitrate (ST decreases at 2 hours, -66%; at 6 hours, -50%; p less than or equal to 0.05 for both), remaining statistically significant up to 12 hours (-24%) than of diltiazem (2 hours, -30%; 6 hours, -16%; p less than 0.05). Combined therapy resulted in increased effects (ST decreases at 2 hours, -80%; 6 hours, -76%; 12 hours, -30%; p less than or equal to 0.05) as opposed to individual substances for a period of up to 12 hours. However, therapeutic coverage over 24 hours could not be demonstrated, even with renewed administration of sustained-release diltiazem in the evening. Plasma concentrations of isosorbide-5-mononitrate were greater than 250 ng/ml for 12 hours on days when isosorbide dinitrate was given, decreasing to less than 100 ng/ml at 24 hours. On days when diltiazem was given, plasma levels greater than 50 ng/ml were detected only at 2 and at 6 hours, and at 24 hours only after a second tablet was given.

Comparison of the anti-anginal efficacy of nicardipine and nifedipine in patients receiving atenolol: a randomized, double-blind, crossover study

The effects of oral nicardipine (40 mg) and nifedipine (20 mg) in combination with atenolol (100 mg) were compared with those of placebo, oral nitroglycerin (0.4 mg) and atenolol alone (100 mg) in 17 patients with stable effort angina. Patients performed symptom-limited, multistage, upright bicycle ergometric exercises with computer-assisted ECG analysis in bipolar lead CM5. Nicardipine and nifedipine were given double blind and in randomized order. In comparison with placebo (4818 +/- 2021 kpm), patients exercised longer and with a greater work load with nitroglycerin (5748 +/- 1711 kpm, P less than 0.001), the combinations of atenolol and nifedipine (6120 +/- 2274 kpm, P less than 0.05), and atenolol and nicardipine (6671 +/- 2339 kpm, P less than 0.01), but not with atenolol alone (5305 +/- 1524 kpm, P = NS). The magnitude of ST-segment depression at peak exercise with placebo (3.22 +/- 1.72 mm) was dramatically reduced with nitroglycerin (1.39 +/- 1.87 mm) but less with atenolol alone (2.95 +/- 1.83 mm, P less than 0.05) or the combinations of atenolol and nicardipine (3.05 +/- 1.51 mm, P = NS), and atenolol and nifedipine (2.45 +/- 1.25 mm, P less than 0.001). Compared to the combination of atenolol and nifedipine, that of atenolol and nicardipine produced a significantly (P less than 0.05) greater exercise tolerance (6671 +/- 2339 versus 6120 +/- 2274 kpm) but with a greater ST-segment depression at peak exercise (3.05 +/- 1.51 versus 2.45 +/- 1.29 mm, P less than 0.01).

Comparison of antianginal efficacies and exercise hemodynamic effects of nifedipine and diltiazem in stable angina pectoris

The antianginal efficacies of nifedipine (40 to 120 mg/day) and diltiazem (120 to 360 mg/day) were studied in 21 normotensive patients with chronic stable angina pectoris, using a randomized, double-blind, crossover design. Patients received each agent titrated to maximum tolerated doses for 6 weeks, after a 2-week placebo baseline period. The maximum tolerated dose for nifedipine was 72 +/- 8 (standard error) mg/day and for diltiazem 297 +/- 20 mg/day. Two patients discontinued nifedipine early because of side effects. Duration of symptom-limited treadmill exercise was longer during the nifedipine (556 +/- 43 seconds) and diltiazem periods (546 +/- 39 seconds) compared with placebo baseline (474 +/- 41 seconds, p less than 0.02). Compared with placebo, nifedipine caused a significant increase in heart rate both at rest standing and at peak exercise. Nifedipine decreased resting systolic blood pressure but had no effect at peak exercise. In contrast, diltiazem caused a significant decrease in heart rate at rest but had no effect on blood pressure at rest or at peak exercise. Thus, nifedipine and diltiazem have differential effects on heart rate and systolic blood pressure suggesting different modes of action. However, despite the increase in exercise duration, neither nifedipine nor diltiazem increased the heart rate-systolic pressure product during maximum exercise. This suggests that the antianginal effects of the 2 agents probably are mediated via reduction of myocardial oxygen demand at submaximal exercise. In addition, diltiazem appears to be better tolerated than nifedipine.

Effects of nifedipine on the hemodynamic response to clamping and declamping of the abdominal aorta in dogs

Clamping and declamping of the infrarenal abdominal aorta may adversely affect cardiovascular function, particularly in the presence of heart disease. This effect may be further altered by drugs used in the treatment of symptomatic coronary artery disease. The effect of nifedipine on the hemodynamic response to aortic clamping and declamping was determined in 12 dogs anesthetized with 50% nitrous oxide and 0.6% end-tidal isoflurane and monitored with aortic, left ventricular (LV), and thermodilution pulmonary artery catheters. Six dogs received a nifedipine bolus of 100 micrograms/kg followed by an infusion of 4 micrograms/kg/min. Six dogs did not receive any nifedipine and served as controls. Before clamping, nifedipine produced immediate decreases in arterial pressure, systemic vascular resistance (SVR), and LV dP/dt, and a modest increase in cardiac output (CO). During aortic clamping, nifedipine-treated dogs demonstrated marked increases in heart rate (HR), dP/dt, and CO while maintaining a low SVR. There were no significant changes upon declamping. The nifedipine-treated animals maintained a high CO and low SVR. Thus, nifedipine greatly altered the hemodynamic responses to aortic clamping and declamping. Awareness of these alterations is important when caring for patients being treated with nifedipine who are undergoing aortic surgery.

Chronic stable angina monotherapy. Nifedipine versus propranolol

A placebo-controlled, double-blind, crossover study was conducted to determine the effects of nifedipine (60 to 90 mg per day) monotherapy and propranolol (240 mg per day) monotherapy on symptoms, angina threshold, and cardiac function in patients with chronic stable angina. Following a two-week placebo period, patients were randomly assigned to receive either nifedipine or propranolol for a five-week treatment period, after which they crossed over to the alternative regimen. All 21 patients were men with chronic stable angina pectoris, 13 of whom had symptoms both at rest and on exertion. New York Heart Association functional class improved in patients taking either nifedipine or propranolol, and nitroglycerin consumption decreased with both treatments compared with placebo. Nifedipine significantly delayed the onset of chest pain and 1 mm of ST-segment depression during bicycle exercise; increases with propranolol were smaller and not statistically significant. Nine patients had a preferential clinical response to nifedipine compared with six patients to propranolol; this was unrelated to the presence or absence of pain at rest or to any baseline hemodynamic finding. Nifedipine and propranolol were equally effective in relieving exertional ischemia as shown by improvement in radionuclide ejection fraction at identical work loads. Exercise wall motion, assessed by a semiquantitative wall motion score, also improved with both drugs. Propranolol treatment decreased exercise cardiac output by 14 percent (p = 0.01) through its effect on heart rate. In contrast, nifedipine treatment had no effect on cardiac output. Thus, nifedipine is more effective on several measurements than propranolol when administered as single drug therapy in stable angina and has the advantage of preserving cardiac output during exercise.

Myocardial properties of the new dihydropyridine calcium antagonist isradipine compared to nifedipine with or without additional beta blockade in coronary artery disease

Isradipine is a new dihydropyridine calcium antagonist with myocardial effects significantly different from those of nifedipine, as shown by in vitro and animal experimental data. Isradipine selectively inhibits the sinus node but not the atrioventricular conduction and its negative inotropic action is much less if administered in a dose of comparable peripheral effects. To study these effects in man, 40 patients with coronary artery disease were divided into 2 groups receiving either a continuous 30-minute intravenous infusion of 2 mg of nifedipine or 0.5 mg of isradipine, doses that resulted in a comparable afterload reduction (decrease of systemic vascular resistance: nifedipine -22.1%, isradipine -25%, p less than 0.001). Ten patients in each group received an additional intravenous bolus of 5 mg of propranolol at the end of the calcium antagonist administration to antagonize its induced adrenergic reflex mechanisms. The heart rate significantly increased after nifedipine only (+9.2%, p less than 0.001), experienced no change after isradipine and the nifedipine and propranolol combination and decreased after the combination of isradipine and propranolol (-9.6%, p less than 0.001). This resulted in a significant decrease of the rate pressure product with isradipine (-12.5%, p less than 0.001) but not with nifedipine. As a result of the afterload-induced adrenergic reflex mechanisms, the maximal derivative of the left ventricular pressure increased after isradipine administration (+13.5%, p less than 0.001) and was unchanged after nifedipine, which demonstrates the significantly less negative inotropic properties of isradipine as compared with nifedipine.

Calcium channel antagonists. Part IV: Side effects and contraindications drug interactions and combinations

With the correct selection of drug and patient, the calcium antagonists as a group can be remarkably effective at relatively low cost of serious side effects. Almost all side effects are dose related. Minor side effects include those caused by vasodilation (flushing and headaches), constipation (verapamil), and ankle edema. Serious side effects are rare and result from improper use of these agents, as when intravenous verapamil (or diltiazem) is given to patients with sinus or atrioventricular nodal depression from drugs or disease, or nifedipine to patients with aortic stenosis. The potential of a marked negative inotropic effect is usually offset by afterload reduction, especially in the case of nifedipine which actually has the most marked negative inotropic effect. Yet caution is required when even calcium antagonists, especially verapamil, are given to patients with myocardial failure unless caused by hypertensive heart disease. Drug interactions of calcium antagonists occur with other cardiovascular agents such as alpha-adrenergic blockers, beta-adrenergic blockers, digoxin, quinidine, and disopyramide. The most marked interaction with digoxin is that with verapamil, which may raise digoxin levels by over 50%. Combination therapy of calcium antagonists with beta-blockers is increasingly common, and is probably safest in the case of dihydropyridines. Other combinations being explored are those with angiotensin-converting enzyme inhibitors and diuretics.

Efficacy of nifedipine gastrointestinal therapeutic system in combination with beta blockers in the management of exertional angina. A multicenter study of 54 patients

This multicenter study assessed the efficacy of a new formulation of nifedipine in 54 patients with stable angina pectoris receiving beta-blocker therapy. This once-daily preparation of nifedipine was administered in double-blind fashion in doses of 30, 60, and 90 mg. All patients experienced pain-limited exercise at placebo baseline treadmill testing. Eight hours post-dose exercise testing resulted in a significant increase in time to onset of angina for all three dose levels of nifedipine but not for placebo. Exercise testing 24 hours after dosing showed significant improvement in time to angina and total exercise time for patients receiving 60-mg and 90-mg doses but not for the 30-mg or placebo categories. These preliminary results suggest that this new formulation of nifedipine is beneficial when added to stable doses of a beta blocker in patients in whom angina is still exhibited during exercise testing.

Comparison of nifedipine and isosorbide dinitrate when added to maximal propranolol therapy in stable angina pectoris

A study was performed to compare isosorbide dinitrate and nifedipine as adjunctive therapy in 14 patients with coronary artery disease and stable angina pectoris taking maximal beta-blocking drugs. Drug titration phases ensured maximal therapy of propranolol, isosorbide or nifedipine. The combination of nifedipine and propranolol was more effective than the combination of isosorbide and propranolol in reducing angina and increasing exercise capacity (323 vs 416 seconds, p less than 0.005) during exercise treadmill testing. Nifedipine produced a greater reduction in systolic blood pressure at submaximal exercise than isosorbide. Global and regional ejection fraction at rest and exercise was assessed with radionuclide ventriculography. The substitution of nifedipine for isosorbide depressed the global ejection fraction at rest (0.61 to 0.56 p less than 0.05) and produced a slight improvement in exercise ejection fraction (0.47 to 0.51, difference not significant). The decrease in ejection fraction from rest to exercise was 0.14 to 0.04 with nifedipine (p less than 0.005). The benefit of nifedipine compared with isosorbide occurred in regions with marked exercise-induced ischemia. In patients treated with maximal beta-blocking therapy, nifedipine is an effective alternative to isosorbide as a combination agent with propranolol. The salutary effects of nifedipine included afterload reduction with exercise and possible improvements in coronary blood supply.

Efficacy of nisoldipine combined with beta-adrenergic-blocking drugs in the treatment of chronic stable angina

A double-blind, placebo-controlled study was performed to assess whether a new calcium antagonist, nisoldipine, in doses of either 5 mg or 10 mg daily, in combination with beta-adrenergic-blocking drugs (combination therapy) was more effective than beta-adrenergic-blocking drugs alone (single therapy) in the treatment of chronic stable angina. Treatments were assessed at two-week intervals, using exercise electrocardiography and patients' anginal diaries. A significant improvement in exercise capacity and reduction in anginal attacks occurred only during nisoldipine (10 mg daily) combination therapy compared with single therapy. Mean exercise time increased from 419 +/- 146 s (single) to 454 +/- 158 s (p less than 0.02) after combination therapy. Exercise time to onset of 1 mm ST-segment depression improved from 326 +/- 145 s (single) to 331 +/- 139 s after combination therapy, although the change was not significant. Mean number of anginal attacks decreased from 21 +/- 22 (single to 15 +/- 19 (p less than 0.01) during combination treatment, with an associated significant reduction in glyceryl trinitrate consumption. Adverse effects during combined therapy were minor and tolerable. Thus patients limited by exertional angina despite beta-adrenergic-blocking drugs may obtain supplemental relief of angina and myocardial ischemia with the addition of nisoldipine in a dose of 10 mg daily.

Long term efficacy of a controlled-release formulation of isosorbide 5-mononitrate (Imdur) in angina patients receiving beta-blockers

In a multicentre double-blind crossover study the clinical efficacy and tolerability of a controlled-release formulation, Durules, of isosorbide 5-mononitrate (Imdur) 60mg once daily was compared with placebo over 2 weeks in 70 patients with stable exercise-induced angina pectoris who were receiving concomitant long term beta-blockade. Isosorbide 5-mononitrate significantly improved exercise capacity and signs of myocardial ischaemia, while reducing the number of anginal attacks and consumption of short-acting glyceryl trinitrate tablets compared with beta-blocker therapy alone. During an open follow-up period of 1 year, there was no attenuation of the antianginal efficacy of isosorbide 5-mononitrate. The drug was well tolerated during both phases of the study, and the only significant adverse effect was headache, which rapidly disappeared during continued treatment.

Changes in haemodynamics and left ventricular function during intravenous nifedipine infusion with and without additional propranolol in patients with coronary artery disease. A randomized, placebo controlled trial

The haemodynamic effects of a combined intravenous treatment of nifedipine and propranolol in ten patients with coronary artery disease compared to a single treatment with nifedipine or placebo were investigated. Nifedipine infusion resulted in a reduction of left ventricular (LV) afterload and LV volumes with an increase in heart rate and EF and no change of the double product, coronary sinus flow, LV diastolic parameters and dp/dtmax. Addition of propranolol lowers myocardial oxygen demand by reducing heart rate and dp/dtmax together with a sustained afterload reduction with no change in LV volumes and EF. The vasodilatatory action of nifedipine pretreatment balanced the negative effects of acute beta-receptor blockade on LV function and allows the reduction of myocardial oxygen demand without a deterioration of LV function.

Who's afraid of angina pectoris? Separating the symptom from the marker

100 cardiologists were asked for their views on the risk associated with an episode of exertional angina in patients with stable angina. 58% thought that such an episode carried some risk of permanent damage or death, and 78% advised their patients to avoid anginal pain. In contrast, exercise studies done during the evaluation of anti-anginal drugs indicate that exertional angina can be provoked frequently and repeatedly without apparent risk, and other studies have shown that repeated exercise to the onset of angina is not only safe but improves exercise tolerance. Epidemiological investigations suggest that sudden death and myocardial infarction do not commonly occur during exertion, and our knowledge of pathology indicates that both events are usually caused by acute coronary thrombosis. Many physicians seem to treat the symptom of angina because they are unduly motivated by fear of the underlying potentially fatal disease for which angina is a marker. Such an attitude will tend to cause undue anxiety among patients, will lead to unnecessary restriction of patients' activities, and may result in excessive invasive treatment of mild angina.

Effects of nifedipine on hemodynamics and cardiac function in patients with normal left ventricular ejection fraction already treated with propranolol

The interaction between nifedipine and propranolol on cardiac hemodynamics and function was investigated in 9 patients with normal left ventricular (LV) function who were undergoing cardiac catheterization for complaints of chest pain. Only 2 patients had angiographic evidence of significant coronary artery disease but no patient had clinical evidence of ischemia during the study. All patients were pre-treated with propranolol, 30 to 320 mg/day (mean +/- standard deviation 210 +/- 122); the propranolol serum level ranged from 43 to 246 ng/ml (mean 203 +/- 62). The administration of nifedipine resulted in a decrease in blood pressure (from 94 +/- 11 to 85 +/- 13 mm Hg, p less than 0.05), increase in heart rate (from 59 +/- 6 to 65 +/- 7 beats/min, p less than 0.05), and an increase in both mean right atrial and mean pulmonary artery wedge pressures (from 8 +/- 3 to 9 +/- 3 mm Hg and from 13 +/- 3 to 14 +/- 4 mm Hg, respectively, both p less than 0.05). Cardiac index increased (from 2.3 +/- 0.3 to 2.7 +/- 0.2 liters/min/m2, p less than 0.01). Stroke volume index also increased significantly (from 39 +/- 5 to 43 +/- 6 ml/m2) and systemic vascular resistance decreased (from 1,715 +/- 369 to 1,255 +/- 271 dynes s cm-5, p less than 0.01). No significant change was noted in pulmonary vascular resistance (148 +/- 94 vs 140 +/- 62 dynes s cm-5), LV stroke work index (44 +/- 9 vs 42 +/- 10 g-m/m2), LV end-diastolic pressure (15 +/- 2 vs 16 +/- 2 mm Hg).(ABSTRACT TRUNCATED AT 250 WORDS)

Changes in myocardial metabolism during therapy in patients with chronic stable angina: a comparison of long-term dosing with propranolol and nicardipine

The long-term effects of antianginal therapy on coronary blood flow and myocardial metabolism were studied in 35 patients with chronic stable angina. Arterial and coronary sinus blood samples and coronary blood flow measurements were obtained before and after 1 month of oral administration of propranolol or of the calcium antagonist nicardipine. When the data obtained at a fixed heart rate (10% to 15% above the pretreatment sinus rhythm) were compared, no significant differences were evidenced between the propranolol and the nicardipine groups. Coronary blood flow and myocardial oxygen uptake were unchanged with both drugs. Myocardial lactate uptake increased in 11 patients of the propranolol group (from -2 +/- 42 to 66 +/- 47 mumol/min, p less than .001) and in 11 patients of the nicardipine group (from 0 +/- 36 to 31 +/- 29 mumol/min, p less than .001). In these 22 patients, the increase in lactate uptake was accompanied by reductions in uptake of free fatty acids and by a decrease in the coronary sinus concentration of thromboxane B2 from 131 +/- 87 to 61 +/- 32 pg/ml (p less than .01), whereas the transcardiac release of prostacyclin increased. None of these changes in free fatty acids or in prostanoid handling were observed in the nine patients (five in the propranolol and four in the nicardipine group) in whom lactate uptake was not augmented. During pacing-induced tachycardia, the metabolic effects of the two drugs appeared different. Myocardial lactate uptake decreased more in the patients receiving propranolol than in those receiving nicardipine and the combined productions of alanine and glutamine rose by 3.2 +/- 5.8 mumol/min in the propranolol group while it decreased by 3.1 +/- 8.2 mumol/min in the nicardipine group (p less than .025 propranolol vs nicardipine). In conclusion, long-term antianginal therapy with propranolol or nicardipine improved several markers of myocardial ischemia in approximately two-thirds of the patients. Although the changes observed at low heart rates were similar with the two drugs, the data also suggest that better metabolic protection is provided by the calcium antagonist during pacing-induced tachycardia.

Comparison of nifedipine alone with propranolol alone for stable angina pectoris including hemodynamics at rest and during exercise

The effects of nifedipine (60 to 90 mg/day) and propranolol (240 mg/day) on symptoms, angina threshold and cardiac function were compared in a placebo-controlled, double-blind, crossover study. Five-week treatment periods with nifedipine and propranolol were compared with 2 weeks of placebo treatment in 21 men with chronic stable angina pectoris, 13 of whom had symptoms both at rest and on exertion. Compared with placebo, New York Heart Association functional class improved in patients equally with nifedipine (p = 0.001) and propranolol (p = 0.006). Frequency of chest pain decreased with nifedipine (p = 0.001) and propranolol (p = 0.01), and nitroglycerin consumption similarly decreased with both treatments. Nifedipine significantly delayed the onset of chest pain (p = 0.01) and 1 mm of ST-segment depression (p = 0.002) during bicycle exercise; smaller increases with propranolol were not statistically significant. A preferential clinical response to nifedipine (9 patients) or propranolol (6 patients) was unrelated to the presence or absence of pain at rest or to any baseline hemodynamic finding. Nifedipine and propranolol were equally effective in relieving exertional ischemia as shown by improvements in ejection fraction at identical workloads, from 0.48 +/- 0.11 to 0.58 +/- 0.12 (p less than 0.001) and 0.56 +/- 0.14 (p less than 0.001), respectively. Exercise wall motion, assessed by a semiquantitative wall motion score, also improved with both drugs. Propranolol treatment decreased exercise cardiac output by 14% (p = 0.01) through its effect on heart rate. In contrast, nifedipine treatment had no effect on cardiac output.(ABSTRACT TRUNCATED AT 250 WORDS)

Rationale for calcium entry-blocking drugs in systemic hypertension complicated by coronary artery disease

There is considerable rationale for the use of the calcium entry-blocking drugs for the treatment of hypertension and prevention of recurrent episodes of angina pectoris in patients with systemic hypertension and significant coronary artery disease--the 2 entities commonly occurring together. Calcium entry-blocking drugs improve myocardial blood flow while decreasing myocardial oxygen demand. These agents can be given to most patients with ischemic heart disease and its complications, and are associated with a relatively low incidence of serious adverse effects and toxicity during long-term therapy. They reduce the frequency of anginal attacks, prolong exercise time to ST-segment depression or angina and improve exercise capacity. With long-term therapy, tolerance does not develop as it does in many patients with the "long-acting" nitrates. Calcium entry-blocking drugs reduce systolic blood pressure in patients with hypertension by a decrease in peripheral vascular resistance and a uniform improvement in blood flow affecting the myocardium, kidney and brain. There are no central nervous system adverse effects and hypokalemia does not occur. Unlike therapy with the beta-blocking drugs, chronic treatment with the calcium entry blockers does not reduce the serum level of high-density lipoprotein cholesterol nor increase serum triglyceride concentration. The calcium blockers decrease the arterial blood pressure without increasing intravascular plasma volume and are associated with only a slight increase in reflex-mediated sympathetic activity and heart rate, the latter occurring predominantly with nifedipine. Calcium entry-blocking drugs provide alternative or preferred therapy to beta-blocking agents in patients with a combination of hypertension and angina pectoris.(ABSTRACT TRUNCATED AT 250 WORDS)

Double-blind crossover comparison of the antianginal effects of nifedipine and isosorbide dinitrate in patients with exertional angina receiving propranolol

A double-blind crossover study was performed on 27 patients with proved fixed coronary artery disease and stable angina pectoris. The study was designed to compare the relative efficacy of two combination therapies, nifedipine plus propranolol and isosorbide dinitrate plus propranolol, in terms of antianginal response and effect on exercise tolerance by evaluation of treadmill testing. The combination of nifedipine and propranolol was superior to the combination of isosorbide and propranolol in reducing the number of anginal attacks (p = 0.03), increasing total exercise time (p less than 0.02), increasing oxygen consumption achieved at end of exercise (p less than 0.03), increasing time to onset of pain (p = 0.003) and increasing oxygen consumption achieved at onset of pain (p = 0.003). Analysis of the rate-pressure products suggests that the difference in these results may be explained by the greater effect of nifedipine on afterload reduction. Although nitroglycerin consumption was reduced from baseline levels during combination nifedipine therapy (p less than 0.001), there was no statistical difference between nifedipine combination therapy and isosorbide combination therapy. In conclusion, although both combination therapies were superior to propranolol therapy alone, the combination of nifedipine and propranolol was more effective than the combination of isosorbide and propranolol in reducing the incidence of angina and improving exercise performance. Side effects were experienced at a similar frequency during both combination therapies.

A dose-ranging, placebo-controlled, double-blind trial of nisoldipine in effort angina: duration and extent of antianginal effects

Maximal treadmill exercise testing at 1, 3 and 8 hours was used to assess the onset, duration and antianginal efficacy of the dihydropyridine slow channel calcium-blocking agent, nisoldipine, in an oral dose range of 5, 10 and 20 mg. A double-blind, randomized, placebo-controlled design was used involving 12 patients with stable effort angina. Exercise tolerance was significantly increased 3 hours after each dose, when the maximal beneficial effect occurred. The improvement was observed as early as 1 hour after the 10 and 20 mg dose, and persisted for 8 hours after the 20 mg dose. At 3 hours, the onset of an exercise-induced ST segment depression of 0.1 mV or greater was increased by 62 (p less than 0.05), 75 (p less than 0.01) and 117 seconds (p less than 0.01) with the 5, 10 and 20 mg dose of nisoldipine, respectively, compared with placebo. Similarly, time to onset of angina was significantly increased. The sum of exercise-induced ST segment depression at peak exercise was significantly decreased (p less than 0.05) from 8.7 +/- 2.3 to 6.7 +/- 1.8 and 6.4 +/- 2.0 mm, respectively, after the 10 and 20 mg dose of nisoldipine. The rate-pressure product was significantly greater with nisoldipine than with placebo at the onset of ischemia and at peak exercise (22.8 +/- 1.1 versus 20 +/- 1.4 X 10(3) U for the 20 mg dose; p less than 0.01). Thus, nisoldipine is an effective antianginal agent with a rapid onset of action that improves exercise tolerance, increases angina threshold and persists for at least 8 hours after oral dosing.

Combination therapy with isosorbide dinitrate: current status and the future

The excellent safety and predictable efficacy of isosorbide dinitrate (ISDN) have been demonstrated repeatedly during the past 25 years in a number of studies in which the agent has been used alone or in combination with other antianginal agents. Clinical studies to investigate the additive or synergistic effect of ISDN have been difficult to conduct because of the complexity of protocol design and length of studies required. However, combination therapy is well accepted in the clinical practice of medicine and cardiology and is used to obtain additive therapeutic effects while minimizing the side effects. The addition of ISDN not only to other standard and proven antianginal agents but also to calcium antagonists should prove to be a fruitful area for further clinical research benefiting patients with angina pectoris (caused by either coronary artery spasm or occlusive coronary artery disease), hypertension, and congestive heart failure. Noncardiovascular uses of ISDN may include the treatment of hyperspasticity of other smooth muscle beds, such as esophageal spasm and achalasia.

Addition of nifedipine to maximal beta-blocker-nitrate therapy: effects on exercise capacity and global left ventricular performance at rest and during exercise

Nifedipine is a potent coronary vasodilator in the resting state and an effective afterload-reducing agent. This study was undertaken because of the concern that the addition of nifedipine to beta-blocker therapy could produce serious untoward hemodynamic consequences. Although this combination is usually well tolerated, occasional reports suggest that the combination of nifedipine and beta-blocking agents may increase the likelihood of congestive heart failure, severe hypotension or exacerbation of angina. Further, there is a need to know if the addition of nifedipine to therapy with maximally tolerated doses of long-acting nitrates and beta blockers would provide further symptomatic relief without excessive adverse effects. Finally, the effect of adjunctive nifedipine on global left ventricular performance at rest and during exercise was examined. Sixteen patients, all of whom had 3 or more episodes per week of angina pectoris despite therapy with long-acting nitrates and beta blockers, were selected. Radionuclide ventriculography was performed at rest and during exercise; global ejection fractions (EFs) were determined by manually tracing the left ventricular end-diastolic perimeter with an electronic cursor. In the first phase, beta blockers and nitrates were used; in the second phase nifedipine, 10 mg every 6 hours, was added and titrated to reduce systolic blood pressure at rest by at least 10 mm Hg or until intolerable adverse effects occurred. When nifedipine was added to therapy, the difference between global EF at rest and during exercise was reduced from - 0.15 to + 0.02 (p less than 0.00001); exercise duration was increased from 431 seconds to 532 (p less than 0.001), with only 8 patients limited by angina, compared with 16 during the initial therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical and hemodynamic evaluation of propranolol in combination with verapamil, nifedipine and diltiazem in exertional angina pectoris: a placebo-controlled, double-blind, randomized, crossover study

The clinical and hemodynamic effects of propranolol, propranolol-verapamil (P-V), propranolol-nifedipine (P-N) and propranolol-diltiazem (P-D) were studied in 19 patients with chronic exertional angina pectoris. A placebo-controlled, double-blind, randomized, crossover study design was used in which patients took each treatment for a 4-week period. The 3 combinations equally reduced the incidence of angina attacks and decreased ST-segment depression. Left ventricular hypokinesia during exercise was lessened and end-systolic volume during exercise decreased with all combinations. Because of a corresponding reduction of normokinetic segmental function, global ejection fraction during exercise remained unchanged. Heart size increased (p less than 0.05) and the PR interval lengthened (p less than 0.001) with P-V and P-D compared to P-N. The largest number of adverse clinical reactions occurred with P-V, whereas the fewest occurred with P-D. Almost all patients preferred combined therapy over propranolol and many favored 1 combination over the others. In summary, when therapy with combined beta- and calcium channel-blocking drugs is planned, P-D should be considered the combination of first choice because of its low incidence of adverse clinical effects. In the presence of possible or definite abnormalities of atrioventricular nodal conduction or decreased left ventricular function, P-N should be considered. Although P-V is associated with frequent adverse reactions, a trial may be warranted if the other combinations are unsuccessful.

Combination therapy with calcium-channel blockers and beta blockers for chronic stable angina pectoris

Combination therapy using calcium-channel blockers and beta blockers in patients with refractory chronic stable angina has gained much popularity, but remains highly controversial because of the potential for serious additive deleterious hemodynamic or electrophysiologic reactions. In studies involving patients with preserved left ventricular function receiving chronic oral beta blockers, short-term administration of intravenous verapamil has been shown to cause a further lowering in heart rate and blood pressure while prolonging atrioventricular node conduction; additive cardiodepressant effects were noted, including a tendency toward increased left and right heart filling pressures. Nifedipine, on the other hand, when added acutely to beta blockers, causes an increase in heart rate, a decrease in blood pressure and either no change or a slight improvement in most cardiac performance variables. Controlled, double-blind clinical trials have demonstrated that combinations of calcium-channel blockers and beta blockers result in augmented symptom benefit compared with either drug class alone. The predominant mechanism responsible for such improvement is increased lowering of myocardial oxygen demand by virtue of additive diminution in heart rate, blood pressure and, consequently, pressure-rate product both at rest and during exercise. Verapamil (and possibly diltiazem) plus beta blockers appears to have the greatest therapeutic efficacy but also the highest frequency of harmful adverse cardiac effects, whereas nifedipine plus beta blockers is generally safer but also less efficacious. Factors that should be carefully considered by clinicians contemplating combination therapy are the choice of calcium-channel blocker, the dose of calcium-channel blocker and beta blocker, the presence of antecedent left ventricular dysfunction or conduction system disease and the possibility of drug interactions. Concomitant calcium-channel blocker and beta-blocker therapy is an important contribution to the pharmacologic management of resistant patients who remain symptomatic during single drug treatment. However, the possibility of additive adverse cardiac effects mandates careful patient selection and close clinical monitoring.

Calcium channel blockers in emergency medicine

Diltiazem, nifedipine, and verapamil inhibit calcium entry into cells via different mechanisms with different pharmacologies. They display different relative effects on different cardiovascular functions, a complex interplay of direct actions and adrenergic reflexes. Peripheral arterial vasorelaxation causes adrenergic reflex activity which opposes their direct negative chronotropic, dromotropic, inotropic, and hypotensive actions. Verapamil's most potent activity is electrophysiologic, and nifedipine's effects are hemodynamic; diltiazem acts like a less-potent combination of verapamil and nifedipine. All three drugs are efficacious in angina. These three drugs may not be interchangeable in all patients, but individualization of therapy is possible. Future indications for calcium channel blocker therapy may include hypertrophic cardiomyopathy, cerebral vasospasm, migraine headaches, pulmonary hypertension, asthma, esophageal spasm, intestinal ischemia, Raynaud's phenomenon, dysmenorrhea, and premature labor.

Calcium blockers in angina. How they work, when to prescribe

The calcium channel blocking drugs--nifedipine, verapamil, and diltiazem--are an important adjunct to treatment of typical exertional angina and are the treatment of choice for angina due to coronary artery spasm. These drugs are as effective as nitrates and beta-adrenergic blocking agents in treatment of patients with ischemic heart disease. With certain precautions, they may also be used in combination with nitrates and beta blockers. The three calcium blockers are not completely interchangeable because each has distinctive therapeutic applications and side effects. Detailed knowledge of each drug is important for its intelligent application in treatment of angina pectoris.