The Grapevine

Less Is More: Heart Attack Patients On Low Dose Beta-Blockers Less Likely To Die Than High Dose Patients

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Heart attack patients who received one-fourth of the recommended dose of beta-blockers had up to a 20 to 25 percent decrease in mortality compared to the full dose group. Reuters

Doctors sometimes prescribe lower doses of a treatment to prevent side effects, such as sexual dysfunction or depression. A new study of heart patients finds lower medicine doses may work best: Patients treated with a lower dosage of beta-blockers following their heart attacks survived at the same rate, or even better rates, than patients on the high doses.

More precisely, the patients who received one-fourth of the recommended dose of medicine had up to a 20 to 25 percent decrease in mortality compared to the full dose group.

“We set out on a mission to show if you treat patients with the doses that were used in the clinical trials, they will do better,” Dr. Jeffrey Goldberger, lead investigator and a professor of medicine in cardiology at Northwestern University Feinberg School of Medicine, stated in a press release. “We were shocked to discover they survived just as well, and possibly even better” when given a lower dosage than in the trial.

Beta-Blockers

The overwhelming majority of heart attack patients are sent home from the hospital with a prescription for beta-blockers, the study authors noted. Beta-blockers are known to prevent a future attack, and they do this by inhibiting the effects of adrenaline on the heart, reducing irregular heartbeats, and generally helping to prevent organ failure. While beta-blockers do their job, they have a few side effects, according to the Texas Heart Institute. These include drowsiness and fatigue, and, in rare cases, impotence, hallucinations, and memory loss. Understanding the side effects, many doctors adjust the recommended dosage for their patients.

So it came to pass Goldberger discovered heart attack patients were being treated with much lower doses of beta-blockers than used in clinical trials. So he launched a new study, dubbed OBTAIN (Outcomes of Beta-Blocker Therapy After Myocardial Infarction), where he and his colleagues examined data from 6,682 patients. All had experienced a heart attack and about 90 percent were currently taking beta-blockers.

First and foremost, the research team discovered all the patients on beta-blockers survived longer than those who did not receive the drugs. The raw figures from OBTAIN also included this breakdown: Among the patients receiving a full dose, 14.7 percent died within two years; among those receiving half a dose, 12.9 percent died; among those receiving a quarter dose, 9.5 percent died; and finally, among those receiving one-eighth dose, 11.5 percent died.

After analyzing this raw data, the researchers noted "higher doses were not associated with better outcome." The team believes more study is needed to determine exactly which dosage strength would benefit most patients.

Source: Goldberger JJ, Bonow RO, Cuffe M, et al. Effect of Beta-Blocker Dose on Survival After Acute Myocardial Infarction. Journal of the American College of Cardiology. 2015.

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