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Abstract
- The first-line symptomatic treatment
for stable angina is a betablocker
such as atenolol. Some calcium
channel blockers such as verapamil,
and the potassium channel agonist
amlodipine, are second-line alternatives.
Long-acting nitrate derivatives
have poorly documented efficacy but
can be used as adjuvants or as thirdline
treatments.
- Ivabradine is derived from verapamil
but appears to have a different
mechanism of action, mainly lowering
the heart rate. It was approved for
sale in Europe through the centralised
procedure for second-line treatment
of stable angina.
- Clinical evaluation of ivabradine
only includes randomised controlled
trials versus two other anti-angina
drugs: atenolol and amlodipine. Three
double-blind randomised controlled
trials lasting 3 to 4 months, based on
surrogate exercise endpoints, failed to
show that ivabradine was any more
effective than atenolol or amlodipine,
or even more effective than placebo in
patients already treated with
amlodipine.
- In two one-year double-blind randomised
controlled trials comparing
ivabradine with atenolol or amlodipine
in a total of 704 patients, ivabradine
was no more effective than the
comparators in preventing angina
attacks.
- In head-to-head comparisons, serious
coronary events were significantly
more frequent with ivabradine than
with atenolol (3.8% versus 1.5%).
Severe arrhythmias were also more
frequent with ivabradine than with
atenolol (1.3% versus 0.7%) or
amlodipine (0.6% versus 0.2%).
- Ivabradine provokes phosphenes
(flashing lights, etc.) in about 17% of
patients in the short term. Information
is inadequate to assess possible
risks of retinal toxicity in the long
term.
- Ivabradine is metabolised by
cytochrome P450 isoenzyme CYP 3A4;
there is therefore a potentially high risk
of pharmacokinetic interactions.