Pharmaceutical dosage forms having a linear release rate of the 0.sup.th order for the once-daily oral administration of 20-120 mg of nifedipine or of another calcium antagonist of the dihydropyridine type, characterised by a homogeneous matrix containing 2-50% by weight of hydroxypropylmethylcellulose having an average molecular weight of 20,000-250,000, 5-60% by weight of a calcium antagonist of the dihydropyridine type, as well as customary excipients compatible with the formulation, such as lipophilic or hydrophilic liberation controllers, fillers, flow-regulating agents, lubricants and, optionally, film coatings.