Dr. Raymond Dong, Cardiologist
Coenzyme Q10 (CoQ10) is a molecule that has been often discussed in the context of treating heart failure. It has been suggested that a failing heart is energy starved. The metabolic pathways within each heart cell are altered and include abnormal calcium handling, depletion of ATP (the primary source of energy that powers each cell) and dysfunction of the components of each cell that produce energy (mitochondria). When these heart muscle cells are depleted of energy, there can be negative effects on contractility.
Some advocates believe that CoQ10 can help protect and invigorate the heart. CoQ10 (also known as ubiquinone) has a prominent role in the production of ATP within the mitochondria. In addition, CoQ10 is a powerful antioxidant and this action may reduce the production of oxidized LDL-cholesterol (which is harmful to arteries). CoQ10 also improves the function of the cells that protect the innermost layer of arteries.
In the clinical setting, lower CoQ10 levels are associated with increasingly severe heart failure symptoms. However CoQ10 levels do not have any prognostic value, and blood levels are difficult to measure in a standardized manner. Studies do show that achieving serum targets of greater than 2 milligram per liter are reasonable to achieve any benefit.
Over the past 30 years, there have been a large number of clinical studies looking at the effect of CoQ10 in heart failure patients. Review of the data from 13 studies (most were completed before 1993) showed a very modest benefit only, with just a 3-4 % improvement in overall heart muscle efficiency. These studies using doses between 60 to 300 milligrams daily over a three month period, on average.
CoQ10 is available as either ubiquinol or ubiquinone, and these supplements are available as tablets, oil suspensions, or powder-filled capsules. They are readily purchased over-the-counter in pharmacies, health-food stores and even online. The average cost for a single 100 milligram tablet runs between $0.17 to $0.42.
CoQ10 is generally well-tolerate, with1.5% of patients reporting an adverse event. Nausea is most common. Laboratory tests remain unchanged and there are slight reductions in blood pressure and heart rate while taking CoQ10 by mouth. There are, however, some drug interactions. The most significant of these appears to be with Warfarin (a commonly prescribed blood thinner). CoQ10 shares some structural similarity with Warfarin and may increase the metabolism of Warfarin. This makes it more difficult to achieve adequate thinning of the blood. Also, it is reported that the use of statins (for lowering cholesterol) may deplete CoQ10 levels.
Current guidelines do not recommend staring nutritional supplementation for the treatment of heart failure. Patients already taking CoQ10 do not necessarily have to stop, as the side effect profile is limited and it appears to do little harm. However a discussion should always occur between the patient and the physician as to the risks and benefits of taking this molecule.
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