Sublingual nifedipine in elderly patients: Even a low dose induces myocardial ischaemia

1. Low doses of sublingual nifedipine are still used for the treatment of h ypertensive crises, although recent studies have raised concerns that subli ngual nifedipine may cause serious dose-dependent adverse effects, The pres ent study was performed to test the safety of low-dose sublingual nifedipin e administered to elderly hypertensive patients. 2. Systemic blood pressure measurements and electrocardiographic (ECG) exam inations were performed before and 45-60 min after a 5 mg dose of sublingua l nifedipine in 93 consecutive hypertensive patients, 65 Sears of age or ol der, who were without coronary artery disease. In 33 patients, the effects of nifedipine on myocardial lactate metabolism were studied during cardiac catheterization. 3. In all patients, following nifedipine administration, blood pressure (BP ) decreased significantly, while heart rate (HR) increased, and symptoms as sociated with elevated BP disappeared. However, changes consistent with myo cardial ischaemia appeared on the ECG in six of 55 patients with left ventr icular hypertrophy (LVH) and in one of 38 patients without LVH, although on ly two of these seven patients experienced angina-like precordial tightness . Sublingual nifedipine decreased myocardial lactate extraction from 52+/-1 3 to 38+/-19% in 20 patients with LVH (P=0.02), but myocardial lactate extr action remained stable in 13 patients without LVH (49+/-7 to 50+/-5%; NS), The change in lactate extraction was significantly correlated with the perc entage change in diastolic arterial pressure (r=0.77, P < 0.001), 4. These results suggest that sublingual nifedipine, even at the low dose o f 5 mg, may cause myocardial ischaemia in some elderly patients with LVH th at is associated with a marked reduction in coronary perfusion pressure.