Study Question: Can coenzyme Q₁₀ prevent further cardiac events in patients who have had a myocardial infarction?

Setting: Inpatient (any location) with outpatient follow-up

Study Design: Randomized controlled trial (double-blinded)

Synopsis: Coenzyme Q₁₀ is a naturally occurring antioxidant. Researchers enrolled 144 participants who were recruited within 72 hours of experiencing an acute myocardial infarction. After stratification for location of the infarction and the presence of complications, patients were randomized (allocation concealment unknown) to receive placebo or coenzyme Q₁₀ in a dosage of 60 mg twice daily for one year.

The patients were relatively young—the average age in the two groups was younger than 48 years. The capsules were not identical, which may have affected blinding. Most (98 percent) of the patients also received ongoing aspirin therapy and were treated to lower their cholesterol levels, although only a small proportion (20 percent) received beta blockers. Despite the randomization, there were more smokers in the coenzyme Q₁₀ group.

Total cardiac events, including cardiac deaths and nonfatal infarction, occurred significantly less often in the treated group (24.6 versus 45.0 percent; number needed to treat [NNT] = 4.9). The outcome of cardiac deaths, nonfatal infarction, and stroke also decreased significantly (24.6 versus 47.8 percent; NNT = 4). Nausea and vomiting were more common in the coenzymeQ₁₀ group, whereas fatigue was reported more often in the control group.

Bottom Line: In this small trial of patients with recent myocardial infarction, coenzyme Q₁₀—used in addition to cholesterol-lowering treatment and aspirin—decreased the likelihood of further cardiac events for at least one year following the event. Although this is a simple and relatively inexpensive intervention, more research is needed before widespread use is appropriate. (Level of Evidence: 1c)