Antihypertensive effects of the calcium antagonistic agent nifedipine

The calcium antagonist nifedipine (Adalat) was administered to 60 patients with essential hypertension and investigations were performed on acute and chronic hypotensive effects. The following results were obtained: 1. Acute hypotensive effects: Nifedipine (20 mg) was either orally or sublingually administered. Following oral administration, significant hypotensive effect was attained 20 min after administration and the maximum hypotensive response was obtained 2-4 h after administration. In cases of sublingual administration, significant hypotensive effect was notable 5 min after administration and blood pressure reached the lowest level 2-3 h after administration. The hypotensive effects lasted for a relatively longer period and significantly lower blood pressure than the control level was observed even 3 h after administration. 2. Chronic hypotensive effects: Nifedipine (30-60 mg/d) was orally administered consecutively. Significant hypotensive effect was attained in and after the 4th week of administration. The yearly changes in the long-term administration cases over 3 years demonstrated significant hypotensive effects. The cases who did not respond to single administration of thiazides or beta-blockers exhibited significant hypotensive response by the combined use of nifedipine. 3. Change in heart rate: In the acute study, heart rate increased after nifedipine administration and lasted for several hours. In the long-term administration cases, the changes in heart rate were not significant. 4. Side effects attributable to nifedipine such as headache in 2 cases, facial flushing, palpitation, warm sensation and nausea in 1 case each were observed early after the administration but there were no cases in whom administration was discontinued due to these side effects.