Once daily felodipine in preventing ergonovine-induced myocardial ischaemia in Prinzmetal's variant angina

The efficacy of extended-release felodipine in preventing ergonovine-inducedmyocardial ischaemia was assessed in 14 patients (12 male, twofemale, aged 56±7 years) with Prinzmetal's variant angina.Four of the patients had normal coronary arteries, eight hadone-vessel and two had two-vessel disease. The ergonovine testwas performed once in basal conditions and twice 5 days afterbeginning the oral administration of felodipine 20 mg o.d.,4 and 24 h after the last administration. During a continuous6-lead ECG recording, ergonovine was injected at doses of 25,50, 100, 200, and 400 µg at 5 min intervals. Blood samplesfor felodipine plasma concentrations were drawn at the timeof the tests. The basal ergonovine test was positive in all 14 patients (sevenwith anterior and seven with inferior ST segment elevation >0•1m V) at a mean ergonovine dose of 162±138 µg. Thetest was repeated 4 h after the last felodipine administrationand was negative in 13 patients (93%), but 24 h after the lastdrug administration, eight patients (57%) had a positive testresponse (five with anterior, three with inferior ST segmentelevation) at a higher ergonovine dose than at baseline (150vs 97 µg, P=0•042). The only dtfferences betweenpatients with a negative and a positive test were the mean valuesof the left ventricular end-diastolic pressure (9•3 vs14•9 mmHg, P=0•002) and the ergonovine doses usedin the baseline tests (250 vs 97 µg, P=0•034). Themean felodipine plasma level 4 h after dosing was 18•0±12•2nmol. l^–1; 24 h post-dosing plasma concentrations weregenerally very low (<3 nmol. l^–1 in eight cases). Noacute side effects were observed during the trial. In conclusion, extended-release felodipine, given once daily,appears to be highly effective in preventing ergonovine-inducedischaemia in patients with Prinzmetal's variant angina, maintaininggood efficacy even 24 h post-dosing.