calcium antagonists , of which the best known are verapamil , nifedipine and diltiazem , are a powerful group of cardioactive agents with a clinical spectrum of indications rather similar to those of beta-adrenoceptor blockade , including angina of effort , angina at rest , hypertension and supraventricular tachycardias ( nifedipine is ineffective for the latter ) .
C0020538
hypertension
C0028066
nifedipine