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From: (Robert R. Fenichel)
Subject: Re: Cardizem info requested...
Date: Fri, 06 Mar 1998 23:57:58 GMT

"Jeff A. Fitzgerald" <> wrote:
>. . .
> The doc recommended that I start taking Cardizem, 120 mg
>once a day.  I'm game for that, but I suspect that this could become a
>permanent prescription and I'm a little apprehensive.  I think I read
>recently that there was a link found between calcium channel blockers and
>heart attacks.

  The allegation of links between calcium-channel blockers and heart
attacks has been discredited.  It had been based on observational
studies, ignoring the massive data from randomized trials.

  Observational studies are difficult to interpret.  They can lead to
absurd conclusions (e.g., because the mortality rate in the ICU is
higher than the mortality rate for other hospitalized patients, you
should refuse to be transferred to intensive care), although of course
they are useful for suggesting hypotheses to test in randomized

  There are 25 randomized trials in which calcium-channel blockers
were given to patients with heart disease (people with heart failure,
people who had just had heart attacks, and so on).  These trials added
up to about 18000 patient-years of exposure to CCBs, and about the
same exposure to controls (mainly placebos).  There were about 2100
deaths, and about 1000 new heart attacks during these trials, and the
risks of heart attack or death were about 10% LOWER in the CCB groups.

  There is one big randomized trial of a CCB  for hypertension.  That
trial (the Syst-Eur trial, published last year by Staessen et al)
followed 4700 patients.  Compared to placebo, the CCB (nitrendipine)
reduced the risk of stroke by 44% and the risk of heart attack by (I
think) 21%.  These numbers are about the same as those seen in trials
of other antihypertensives.

  The CCB hysteria was reviewed by a committee appointed by the World
Health Organization; the committee included some of the top
epidemiologists of the world.  Their report (last year in Journal of
Hypertension) reviews a superset of what I mention above, with the
same conclusion.

>I also wonder about side effects of long term usage.

  Diltiazem has been around for about 15 years, but no one has done
any trials that last that long.  If you want to take an
antihypertensive that is CERTAIN not to grow tails on 100% of the
people who take it for >20 years, you'll need to look elsewhere.
            Robert R. Fenichel, M.D.

(true email address is as above, but without initial NOTQUITE)

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