Monday, October 5, 2015

Lowering Beta-Blocker Dose May Boost Survival After Heart Attack

People treated with low-dose beta blockers after a heart attack may fare better than those given the standard dose of this commonly prescribed medication, a new study shows.

Heart attack patients given just one-fourth of the dosage used in clinical trails lived just as long as patients on a higher dose, according to researchers at Northwestern University in Chicago. And in some cases, those on a low dose lived even longer, with 20-25% increase in survival.

“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. We expected to see patients treated with the lower doses to have worse survival,” lead investigator Dr. Jeffrey Goldberger said in a university news release. “We were shocked to discover that they survived just as well, and possible even better.”

Goldberger is a professor of medicine at Northwestern’s Feinberg School of Medicine and a cardiologist at Northwestern Memorial Hospital. He also directs the cardiac arrhythmia program at Feinberg’s Center for Cardiovascular Innovation.

“We now need to figure out how to dose it in individual patients. That’s something no one has considered in the decades that we have been using this medication,” Goldberger said. “This huge gap in knowledge has been completely unexplored. Since this is the medicine we use in every single heart attack patient, we ought to figure out how to use it properly,” he said in the news release.

Roughly 90% of people treated for a heart attack are given a beta blocker, the study authors noted. This class of medication, which includes metoprolol (Toprol XL) and acebutolol (Sectral), is used to improve survival and prevent further heart attacks.

Beta-blockers work by blocking the effects of adrenaline on the heart. They also reduce irregular heartbeat and help prevent heart failure. Some patients are treated with low doses of the drug if there are greater concerns about possible side effects, such as fatigue, sexual dysfunction and depression. the study authors said.

My Take:
This was a poorly designed study that may provide some benefit by sheer coincidence. You don’t start a study with a “mission to show if you treat patients with the [standard dose] they will do better.” The study should have been to discover what dosage was optimal under what circumstances.

To the investigators credit, they still published. Now it remains to be seen if medical protocol for prescribing beta-blockers will change. It’s just common sense that the dose should be dependent on factors like weight, sex, physical fitness, and medical history rather than if they can tolerate the side effects.
The most common side effect of beta-blockers is congestive heart failure. When you reduce to force of the heart contraction, fluid pools in the lower extremities (edema). This reduces the return of blood to the heart which is by definition, congestive heart failure. Typically, a diuretic is added to the beta-blocker to reduce the edema. Then potassium is prescribed to counteract the loss from the diuretic. Finally, a proton-pump inhibitor is thrown into the mix to reduce the gastric distress caused by the potassium.

Welcome to the American health care system where the average citizen takes four prescriptions daily. Rarely, if ever, are these prescriptions discontinued but frequently additional drugs are added. It is not unusual for me to see patients taking ten or more prescription drugs. Usually, there are contraindications to mixing many of these drugs and more often than not, the side effects are the symptoms that they related to me on entry.

The Bottom Line:
The chemical mechanism of most drugs is poorly understood at best. Often the mode of action is unknown. Just because your physician accepts the medical standards for treatment doesn’t mean you have to blindly follow. Please review the side effects and contraindications for all medications that are recommended for you. It’s your health and you need to protect it.

Source: September 21, 2015 National Institutes of Health

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