| Summary: | Context - Calcium channel blockers (CCBs) are widely used drugs to lower elevated blood
pressure and manage angina and arrhythmias. Although the goal of antihypertensive therapy
is to lower the risk of cardiovascular disease-related morbidity and mortality, efficacy is most
often gauged by blood pressure reduction.
Objectives — This systematic review of the blood pressure lowering efficacy of CCBs aims
to determine the dose-related changes in systolic blood pressure (SBP), diastolic blood
pressure (DBP), heart rate, and withdrawals due to adverse events (WDAE) with CCB
treatment compared with placebo for a duration of 3-12 weeks, in patients with primary
hypertension (SBP [greater than or equal to] 140 mm Hg and/or DBP [greater than or equal to] 90 mm Hg).
Design — A systematic review, as per the methodology of the Cochrane Collaboration, of
randomized placebo-controlled trials.
Methods - Electronic databases were searched using a modified, expanded version of the
search strategy used by the Cochrane Hypertension Review Group. RevMan 4.2 software
was used to analyze data.
Participants — 106 trials were included and reported data on 13 878 patients with a mean
age of 55 years, mean baseline blood pressure of 158.2/101.6 mm Hg, mean pulse pressure
of 56.7 mm Hg, and mean treatment duration of 5.7 weeks.
Results — Maximal blood pressure lowering efficacy of CCBs is achieved at twice the
manufacturer's recommended starting doses. This maximal reduction is 10/7 mmHg for
dihydropyridines and 8/6 mmHg for non-dihydropyridines and likely represents an
overestimate of the true blood pressure lowering effect due to publication bias. Combined,
dihydropyridines and non-dihydropyridines lower pulse pressure by 3 mm Hg (95% CI: -4, -
2). Compared with placebo, WDAE increased in a dose-related fashion for dihydropyridines
[relative risk of 1.8 (95% CI 1.2, 2.6) at 2 times the starting dose compared with 3.9 (95% CI:
2.2, 7.0) at 4 times the starting dose]. There were insufficient data to make a conclusion
about the effect of non-dihydropyridines on WDAE.
Conclusion — Dihydropyridines reduce blood pressure to a greater degree than nondihydropyridines.
Maximal blood pressure lowering for both subclasses occurs with twice
the manufacturer-recommended starting dose. Increasing the doses of dihydropyridines
above recommended starting doses increases withdrawals due to adverse effects. === Medicine, Faculty of === Anesthesiology, Pharmacology and Therapeutics, Department of === Graduate
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