P-82: Responses of blood pressure and of heart rate to the first dose of two calcium antagonists

The responses of BP and of radial pulse rate (HR) to the first dose of 4 mg lacidipine (L) and of 30 mg nifedipine GITS (N) were assessed as part of the Latin American Study of Lacidipine in Hypertension. Patients with sitting diastolic BP (D) of 100-115 mmHg at the end of a 4-week placebo run-in were randomly assigned to open treatment with L or with N. The first dose was taken at experimental hour (EH) 0. S: systolic BP.L, which is absorbed more rapidly than N, decreased BP quicker and caused an earlier reflex increase in HR than N. In a similar study, HR was found to increase by 15-18 b.p.m. 60 min after intake of 10 mg of classic nifedipine (Hernández R, et al. Arch Ven Farmacol 1985;2:315-322). (See Table) L group (n = 120) L vs. N§ N group (n = 128) Mean ± SD Mean ± SD Time (EH) BP (mmHg) HR (b.p.m) S/D/HR BP (mmHg) HR (b.p.m.) 0 155 ± 16 101 ± 6 75 ± 8 −/−/− 154 ± 17 102 ± 5 75 ± 7 0.5 147 ± 16* 97 ± 8* 77 ± 10* a/c/− 153 ± 17 100 ± 7 75 ± 8 1 142 ± 15* 92 ± 9* 79 ± 9* c/c/b 151 ± 16* 99 ± 8* 75 ± 7 1.5 141 ± 13* 91 ± 9* 79 ± 10* c/c/b 150 ± 17* 98 ± 8* 75 ± 8 2 140 ± 14* 91 ± 9* 79 ± 9* c/c/c 148 ± 16* 97 ± 8* 75 ± 7 2.5 139 ± 14* 91 ± 8* 78 ± 9* c/c/b 147 ± 16* 96 ± 9* 75 ± 7 3† 140 ± 14* 91 ± 8* 78 ± 9* b/c/a 145 ± 16* 95 ± 9* 75 ± 7 3.5 139 ± 14* 90 ± 8* 78 ± 9* b/b/− 144 ± 16* 94 ± 9* 76 ± 8 4 139 ± 15* 91 ± 8* 79 ± 10* −/−/− 143 ± 16* 93 ± 9* 78 ± 9* 4.5 140 ± 14* 91 ± 9* 79 ± 9* −/−/− 142 ± 16* 92 ± 9* 78 ± 9* 5 140 ± 14* 91 ± 9* 79 ± 9* −/−/− 141 ± 15* 92 ± 9* 78 ± 8* 5.5† 142 ± 14* 92 ± 9* 78 ± 9* −/−/− 142 ± 16* 92 ± 9* 78 ± 8* 6†‡ 142 ± 15* 92 ± 9* 78 ± 9* −/−/− 141 ± 16* 92 ± 9* 78 ± 9* †L group: n = 119; ‡N group: n = 127. *Comparisons with EH 0 (ANOVA for repeated measurements and Dunnett's test): P < 0.01. §P values: a < 0.05; b < 0.01; c < 0.001; −: > 0.05.