A randomized, placebo-controlled study of the effects of telcagepant on exercise time in patients with stable angina.

Telcagepant is a calcitonin gene-related peptide (CGRP) receptor antagonist being evaluated for acute migraine treatment. CGRP is a potent vasodilator that is elevated after myocardial infarction, and it delays ischemia during treadmill exercise. We tested the hypothesis that CGRP receptor antagonism does not reduce treadmill exercise time (TET). The effects of supratherapeutic doses of telcagepant on TET were assessed in a double-blind, randomized, placebo-controlled, two-period, crossover study in patients with stable angina and reproducible exercise-induced angina. Patients received telcagepant (600 mg, n = 46; and 900 mg, n = 14) or placebo and performed treadmill exercise at T(max) (2.5 h after the dose). The hypothesis that telcagepant does not reduce TET was supported if the lower bound of the two-sided 90% confidence interval (CI) for the mean treatment difference (telcagepant-placebo) in TET was more than -60 s. There were no significant between-treatment differences in TET (mean treatment difference: -6.90 (90% CI: -17.66, 3.86) seconds), maximum exercise heart rate, or time to 1-mm ST-segment depression using pooled data or with stratification for dose.

Abrupt cessation of short-term continuous treatment with isosorbide dinitrate may cause a rebound increase in silent myocardial ischaemia in patients with stable angina pectoris.

OBJECTIVE: To examine by Holter electrocardiographic monitoring the effect of abruptly stopping nitrate treatment in patients with stable angina pectoris. PATIENTS: 12 men with confirmed ischaemic heart disease and stable exertional class 3 angina (Canadian). All had episodes of horizontal or down sloping ST segment depression during 24 hour electrocardiographic monitoring. All were nitrate responders. DESIGN: Each patient was given isosorbide dinitrate (10-30 mg four times a day) and placebo (four times a day) for three days in a randomised crossover trial. There was a washout period of 3-5 days between the two treatment periods. Holter monitoring was performed on the third day of isosorbide dinitrate and placebo administration and on the first day of their withdrawal. RESULTS: When treatment with isosorbide dinitrate was stopped there was a significant increase in the total number and duration of painless episodes of myocardial ischaemia. During placebo and isosorbide dinitrate administration 8 patients had episodes of painless myocardial ischaemia whereas after isosorbide dinitrate cessation they were recorded in all 12 patients. Episodes of silent myocardial ischaemia at rest appeared in 4 patients after isosorbide dinitrate withdrawal. CONCLUSION: Abrupt cessation of short-term continuous nitrate treatment in patients with severe angina may cause a rebound increase in myocardial ischaemia which is predominantly silent.

Withdrawal phenomenon after abrupt cessation of nifedipine in stable angina pectoris.

We investigated the effect of abrupt cessation of nifedipine after regular administration (20 mg, four times daily) for 5 weeks in seven patients with stable angina pectoris. A rebound decrease in exercise tolerance and increase of exercise-induced myocardial ischaemia were registered on the first day of nifedipine withdrawal.

Development of tolerance to nifedipine in patients with stable angina pectoris.

1. The possibility of development of tolerance to the anti-ischaemic and anti-anginal effects of nifedipine during sustained administration for 2 months was studied in 15 patients with stable angina pectoris by means of repeated exercise tests on a treadmill. 2. After acute administration of nifedipine (20-30 mg) substantial anti-ischaemic and anti-anginal effects lasted for at least 4 h in all patients. 3. During sustained nifedipine treatment with a dose schedule which provided continuous anti-ischaemic effect during a day (mean daily dose 82.7 +/- 6.0 mg, range 60-120 mg) a substantial attenuation of this effect was registered. The duration of the anti-ischaemic effect was 5.4 +/- 0.3 h after acute administration, decreasing significantly to 3.6 +/- 0.4 h during sustained administration. 4. The attenuation of the nifedipine effect was not associated with worsening of the patients' condition. 5. Plasma concentrations of nifedipine and its metabolite were similar after acute administration and during sustained treatment. Protein binding of nifedipine also remained constant during the study. 6. There was marked interindividual variation in the degree of attenuation of the nifedipine effect during sustained administration. In five patients nearly complete loss of nifedipine efficacy was registered. Eight to ten days after stopping regular administration of nifedipine only partial restoration of nifedipine effect was observed. 7. We conclude that during sustained nifedipine administration tolerance to its anti-ischaemic, anti-anginal and circulatory effects develops in a substantial number of patients with stable angina pectoris.