Problems associated with clinical evaluation of antianginal medications

Comparative evaluation of three dosages of slow-release isosorbide dinitrate (60, 80, 100 mg) in chronic angina of the aged

In a single-blind, placebo-controlled study the acute and chronic antianginal effects of three slow-release (SR) new formulations of isosorbide dinitrate (ISDN 60, 80, 100 mg) have been comparatively evaluated in a group of aged affected by chronic stable effort-induced angina. Compared to placebo, overall the active dose paritetically improved the effort tolerance up to 24 h after the first assumption. In the time course of the trial (2 and 4 weeks) the resting hemodynamic changes induced by the first dose were partially blunted without affecting the exercise related-parameters. Also if plasma levels of ISDN and of its metabolites did not correlate to the degree of physical improvement, the peak increase in effort tolerance was observed under 100 mg treatment. Mild to moderate transient headache was experienced by 50% of actively treated and by 20% of placebo treated patients and no other serious adverse effects have been noted. One may conclude that ISDN in slow-release formulations of 60-100 mg isan effective, safe and well tolerated medication in the management of angina in the aged.

Factors of importance when evaluating quality of life in clinical trials

Quality of life (QoL) has during recent years become recognized as an important outcome in clinical trials. But it is not sufficient just to incorporate QoL measures in a trial. Several factors have important repercussions on the results of clinical trials using QoL as an outcome measure. Unless more attention is directed towards factors that may be important when evaluating QoL, the value of including these measurements in clinical trials will be minimized. Important issues pertain to trial design, duration of follow-up, the role of placebo effects, side effects, and confounding variables.

Efficacy of nicardipine in angina pectoris

The dose-related efficacy and safety of nicardipine, a new calcium antagonist of the dihydropyridine class, was assessed by exercise tolerance testing in a randomized, double-blinded, placebo-controlled study in 19 patients with chronic, stable effort angina pectoris. Four patients were assigned to each of four treatment sequences receiving nicardipine three times daily in an extended Latin-Square study design. An increase in total exercise capacity, time to onset of angina and time to 1 mm ST segment depression was observed with nicardipine 90 mg/day compared to placebo (P less than .05). Gradual upward dose titration in 30 mg/day increments starting from 30 mg/day appeared to produce maximal increase in exercise capacity. Two patients developed adverse side effects attributable to the drug when administered nicardipine 90 mg/day directly from placebo.

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).

Individual responses to transdermal nitrates after chronic administration in angina pectoris

The aim of this study was to investigate whether, and to which extent, sustained treatment with transdermal nitroglycerin plasters may lead to the development of tolerance in patients with effort-induced angina pectoris. Ten patients, all men, mean age 62.7 years, took part in a double-blind, cross-over, acute study, comparing the transdermal therapeutic system of nitroglycerin 10 mg/24 hours with placebo. Patients were then treated for 1 month with the active drug in single-blind condition, and finally they took part in a further acute study identical to the first. Cycloergometric exercise tests were carried out 4 hours after dosing. In comparison with placebo, the active drug significantly (P less than 0.01) increased ischaemic threshold (ST depression = 1 mm) after both acute (from 299 +- 92 to 413 +- 120 sec) and chronic treatment (416 +- 107 sec). The same results were obtained for exercise duration to peak exercise (acute study: from 336 +- 65 to 482 +- 90 sec; chronic treatment: 466 +- 118 sec). The final acute study confirmed the stability of angina, showing that the improvement in exercise tolerance after chronic treatment was entirely due to the pharmacological effect of the drug. In terms of single patient response to the active treatment, 7 of the 10 patients showed an improvement in exercise tolerance after both acute and chronic treatment, while in 3 patients no antianginal effect was observed. These results suggest that nitrate tolerance cannot be considered an inevitable finding in patients chronically treated with transdermal patches.

Acute and sustained antianginal effects of nitroglycerin patches: objective evaluation with training-effect-eliminated exercise performance index

A randomized within-patient double-blind acute and sustained study was performed to compare transdermal nitroglycerin (NTG) patches (5 and 10 mg) and matching placebo in 10 patients with chronic stable angina pectoris confirmed on exercise thallium scintigraphy or coronary angiography, or both. Patients performed treadmill tests 2 and 24 hours after application of patches on the first and last days of each of the 3 treatment periods. Effects caused by sequence of treatments and training with serial testing were prominent so the changes in the well-known parameters did not favor either of the active doses over placebo. Quantification of training effects and its subtraction from performance index disclosed that 10 mg of transdermal NTG caused significant increase in performance in both the acute and sustained stages of therapy in comparison to pretreatment performance. This was not observed with 5 mg and placebo treatments. To our knowledge, this is the first trial to study the efficacy of transdermal NTG with a more objective parameter that permitted elimination of training effects of serial exercise testing.

Clinical experience with a transdermal nitroglycerin system

Forty-seven patients with chronic stable angina pectoris entered a thirteen-week open-label study with a transdermal therapeutic system of nitroglycerin in order to evaluate its clinical efficacy, safety, and patient acceptance. In 19 patients, a beta-blocker and in 17 patients a calcium-channel blocker were continued throughout the study period without alteration of their doses. The study consisted of a two-week run-in period and an eleven-week active drug period. Acute titration was done with nitroglycerin patches on the basis of weekly patient diaries on frequency of angina and sublingual nitroglycerin consumption. Overall, reductions in frequency of angina and in nitroglycerin consumption were statistically significant (p less than 0.05). Adverse reactions were common but tolerable. The reported side effects were headache in 32, skin rash in 18, dizziness in 10, palpitation and itching in 9 each, nausea in 7, flushing in 3, and vomiting in 1 patient. In conclusion, the present study demonstrates that individual dose titration with nitroglycerin patches for obtaining significant antianginal effect is essential. The present therapeutic system is convenient to use and well tolerated and had acceptable side effects in our study population.

Alternative medical treatment for patients with angina pectoris and adverse reactions to beta blockers. Usefulness of nifedipine

Although beta blockers are effective for the treatment of angina pectoris, chronic adverse effects produced by these agents--including lethargy, fatigue, and male impotence--can adversely affect patient acceptance and treatment compliance. To assess the clinical effects of switching from anti-anginal treatment with beta blocker only (phase I) to half-dose beta blocker plus the calcium blocker nifedipine (phase II) or nifedipine alone (phase III), 18 patients with chronic stable angina pectoris and side effects to beta blockers were evaluated in a 12-week, open-label trial. Three patients did not complete the study, one secondary to new unstable angina and two secondary to nifedipine side effects. Of the 15 patients completing the trial (13 men and two women; mean age, 54 +/- 5 [SEM] years), all sequentially participated in the one-month phases. Weekly angina frequency assessed from patient diaries was significantly less for treatment with nifedipine only (phase III) as compared with beta blocker (phase I) (1.7 +/- 1 versus 3.9 +/- 1 episodes per week), while phase II was not significantly different. Exercise test time was maintained throughout all phases (phase I, 457 +/- 39; phase II, 458 +/- 40; and phase III, 498 +/- 48 seconds, p not significant). All 15 patients in phase I (100 percent) had side effects to beta blockers, but these side effects were lessened in 12 patients (80 percent) in phase II and 13 patients (86 percent) in phase III, with total alleviation of symptoms in two patients (13 percent) in phase II, and eight patients (53 percent) in phase III. Thus, in patients with side effects to beta blockers, switching to nifedipine is associated with a significant reduction in beta blocker adverse symptoms and equal anti-anginal efficacy.