6 It was once suggested that calcium channel
blockers might be dangerous for treating
hypertension. Is this still true?
Kieran Bhagat
Innumerable editorials, reviews and letters have been written on
the calcium channel blocker controversy that started with the publi-
cation of the case-control study by Psaty et al in 1995^1 and the subse-
quent meta-analysis of Furberg et al in the same year.^2 They reported
a greater increase in the risk of myocardial infarction among those
taking short-acting calcium channel blockers than amongst those
taking diuretics or beta-blockers. The risk was greatest at higher
doses of nifedipine. Other concerns relate to an increase in gastroin-
testinal haemorrhage, bleeding in relation to surgery and cancer.
Since then three further case-control studies have not found an
association between calcium channel blockers and adverse cardio-
vascular outcome, while a leash of prospective trials have added
greatly to the quality of the data available on this issue.
There is general consensus that short-acting dihydropyridines
should not be given to patients with ischaemic heart disease. The
position in hypertension is less clear. There do seem to be
grounds for concern about short acting dihydropyridines relative
to other treatments. The recent case-control studies do not seem to
raise the same concerns with long-acting agents, at least from the
point of view of adverse cardiovascular outcomes. However, the
real safety profile of these agents in hypertension will not be
known until many ongoing prospective randomised trials such as
ALLHAT report.^3 Despite the absence of these trials a prudent
interim approach would be to restrict the use of calcium
antagonists to the newer slow-release formulations that, by virtue
of their ability to attain more gradual and sustained plasma
levels, do not evoke a reactive sympathetic activation.
RReeffeerreenncceess
1 Psaty BM, Heckbert SR, Koepsell TD et al. The risk of myocardial
infarction associated with antihypertensive drug therapies. JAMA
1995; 227744 : 620–5.
2 Furberg CD, Psaty BM, Meyer JV. Nifedipine. Dose-related increase
in mortality in patients with coronary heart disease.Circulation1995;
9922 : 1326–31.