As in
hypertension, the addition of a second active
drug is believed to enhance treatment efficacy; however, the extent to which a combination of two low-dose drugs outperforms conventional monotherapy remains uncertain. Established treatments of angina comprises
nitrates compounds, beta-blockers and
calcium antagonists, which are often given in combination. Beta-blockers are major players in this field as they inhibit the
tachycardia induced by
nitrates and
calcium antagonists; there is therefore a pathophysiological justification for their use in combination
therapy, supported by repeated confirmation of positive clinical effect. The most widely chosen
calcium antagonists are
dihydropyridines;
verapamil may impair conduction. However, it is not clear whether combination enhances the effects of the individual antianginal substances.
Diuretics are for most clinicians the keystone treatment of
heart failure;
diuretics are often combined with other drugs, e.g.
amiloride and
spironolactone. The latter also have a beneficial effect on myocardial structure (myocardium/
collagen ratio).
ACE-inhibitors are of proven clinical efficacy, and, in addition, have a beneficial effect on survival. They combine well with
diuretics: because the
diuretic stimulates
renin release, the
ACE-inhibitor can be given at a lower dose (enhancement of effect). There are, however, certain drawbacks (
hypotension,
hyperkalemia with antialdosterones). The results of combining
ACE-inhibitors with
calcium antagonists and beta-blockers await investigation. The ISIS studies demonstrated the advantages of combining beta-blockers, thrombolysis and
aspirin in acute
infarction.
ACE-inhibitors have recently been added to the regimen with a positive effect (extended survival), especially in the presence of a decreased ejection fraction (SAVE, AIRE, GISSI 3 and ISIS 4 studies).(ABSTRACT TRUNCATED AT 250 WORDS)