Beta Blockers: Not All the Same
In one of the few head-to-head comparisons of the three beta-blockers most commonly prescribed after acute myo-cardial infarction (AMI), atenolol (Tenormin generic, AstraZeneca) and acebutolol (Sectral, ESP Pharma) reduced mortality rates better than metoprolol succi-nate (Toprol generic, AstraZeneca), say researchers in Canada. Their findings, they say, challenge the concept of a class effect after an AMI. The class effect of beta blockers has been investigated in patients with congestive heart failure or in non-cardiac surgery patients.
Among 31,576 patients, 67% received metoprolol; 24%, atenolol; and 9%, acebu-tolol. Overall, the patients were elderly (median, 74 years of age) and at high risk, with a median length of hospital stay of eight days.
In all analyses, acebutolol and atenolol drug were associated with a statistically significant reduction in mortality, compared with medication metoprolol.
The reasons remain uncertain but are unlikely to be related to the dosage or the indication. Although patient compliance in refilling prescriptions and persisting with the regimens were similar for all three study groups, the researchers suggest that twice-daily dosing of metopro-lol might at least partly explain their findings: missing a dose might cause acute withdrawal. Although patients taking the other two drugs might also miss doses, it is possible that longer half-lives would make the effects less deleterious.
