AT EQUIPOTENT DOSES, ISRADIPINE IS BETTER TOLERATED THAN AMLODIPINE IN PATIENTS WITH MILD-TO-MODERATE HYPERTENSION - A DOUBLE-BLIND, RANDOMIZED, PARALLEL-GROUP STUDY
L. Hermans et al., AT EQUIPOTENT DOSES, ISRADIPINE IS BETTER TOLERATED THAN AMLODIPINE IN PATIENTS WITH MILD-TO-MODERATE HYPERTENSION - A DOUBLE-BLIND, RANDOMIZED, PARALLEL-GROUP STUDY, British journal of clinical pharmacology, 38(4), 1994, pp. 335-340
1 The objective of this double-blind parallel-group study was to compa
re the tolerability of isradipine and amlodipine, specifically, the si
de-effects known to be related to the use of dihydropyridine calcium a
ntagonists. 2 A total of 205 patients with mild-to-moderate essential
hypertension were randomized to receive either the sustained-release (
SRO) formulation of isradipine (n = 103) Or amlodipine (n = 102), both
at dosages of 5 mg once daily. Blood pressure measurements were taken
at the end of the dosing interval to assess the antihypertensive effi
cacy of the two drugs. 3 Adverse reactions were assessed in two ways:
a) spontaneously reported adverse events were recorded and investigate
d in depth for severity, duration, relation to the study drug, and out
come; b) a questionnaire was used to elicit specific adverse reactions
known to be related to the use of dihydropyridine calcium antagonists
which were evaluated for severity, duration, relation to the study dr
ug, and outcome. 4 After 6 weeks of active treatment, both isradipine
and amlodipine reduced mean sitting systolic/diastolic blood pressure:
from 165.1/100.1 to 145.2/89.7 mm Hg with isradipine; and from 164.1/
100.6 to 145.7/90.5 mm Hg with amlodipine. There was no difference in
antihypertensive effect between isradipine and amlodipine (95% CI: -3.
73 to 4.73 and -1.89 to 3.49 for differences in systolic and diastolic
blood pressure, respectively). 5 The number of patients spontaneously
reporting adverse events was significantly higher (P = 0.02; 95% CI:
3.1 to 26.7%) with amlodipine (33.3%) than with isradipine (18.4%). 6
The incidence of spontaneously reported ankle oedema was statistically
significantly greater with amlodipine than with isradipine (14.7% vs,
5.8%, respectively, P = 0.04). In addition, the severity (P = 0.02) a
nd duration (P = 0.03) of the ankle oedema was greater with amlodipine
than with isradipine. Moreover, eight patients taking amlodipine disc
ontinued treatment due to this side-effect compared with none of the p
atients taking isradipine. 7 By questionnaire, the severity (P = 0.03)
and duration (P = 0.02) of nausea as well as the severity of ankle oe
dema (P = 0.04) were greater with amlodipine than with isradipine. 8 I
n conclusion, at equipotent antihypertensive doses, isradipine compare
d with amlodipine treatment resulted in a statistically significantly
lower incidence of spontaneously reported adverse events in general an
d of ankle oedema in particular.