All concepts, explanations, trials, and studies have been re-written in plain English and may contain errors. I am not a doctor ----------------------------------------------------------- NOTE: You can make the print bigger with the font button on your browser! (It's usually a big "A") ----------------------------------------------------------- Title: Role of Coenzyme Q10 in Chronic Heart Failure, Angina, and Hypertension. Authors: Mongthuong Tran, Tina Mitchell, Daniel Kennedy, Joel Giles. Source: Pharmacotherapy 21(7):797-806, 2001. We used information from clinical trials, articles, reviews, and letters in Medline between 1974 and 2000, the Micromedex Healthcare Series, and the Natural Medicines Comprehensive Database to research this review. SUMMARY Oral CoQ10 supplements may help heart failure and angina patients. CoQ10 is safe and well tolerated. Best dose and possible interactions need more research. Favorable effects of CoQ10 on ejection fraction, exercise, cardiac output, and overall heart function are proven. Using CoQ10 as added therapy in CHF patients is supported. ==================== LONG VERSION - INTRODUCTION In 1957, researchers at the University of Wisconsin found the molecule in beef hearts. It was also found in yeast by a group of English researchers and was named ubiquinone. Other names include ubidecarenone and ubiquinone. Several years later, the University of Wisconsin group showed that this molecule was a coenzyme - a substance necessay for an enzyme system to be active. CoQ10 is also a provitamin - a substance that may become a vitamin in the body. CoQ10 is found in plants and mammals, including humans. Coenzymes Q6, Q7, and Q8 are found in yeast and bacteria, while CoQ9 is found in rats and mice. CoQ10 is abundant in humans, with high levels in the heart, liver, kidneys, and pancreas. CoQ10 can be received through beef, poultry and broccoli. Current CoQ10 supplements are manufactured by fermenting beets and sugar cane. By 1974, the Japanese government approved CoQ10 for treating chronic heart failure, and about 250 CoQ10 preparations are available in Japan for treating heart-related diseases. CoQ10 is involved in chain of events that produces energy in the human body - the cell-level electron movement leading to production of ATP (adenosine 5- triphosphate). Low CoQ10 levels in the body are well documented in heart failure. The worse the heart failure, the lower the CoQ10 level usually is. ACTIONS (technically speaking) CoQ10 is similar in structure to vitamin K. CoQ10 production in the body is regulated through the same channels that statin cholesterol-lowering drugs inhibit. CoQ10 acts in at least 3 ways. It is a vital part of the energy (ATP) chain. It is an antioxidant. It has membrane-stabilizing properties. CoQ10 directly regulates some enzyme reactions in the cells' electron transport system. CoQ10 may also prevent the loss of substances (metabolites) necessary for energy production. CoQ10 must be reduced to its basic parts to be an antioxidant. Taking CoQ10 may reduce cholesterol oxidation. Despite this, CoQ10 seems to have a "sparing" effect on vitamin E in the human body. Other CoQ10 actions may include stabilizing certain calcium channels, inhibiting certain harmful substances, and changing prostaglandin metabolism. CoQ10 is reported to slightly increase the pumping strength of the heart like digoxin does. INSIDE THE BODY (technically speaking) Taking 30 mg of CoQ10 orally increases average peak CoQ10 blood level to about one microgram/ml within 6 hours, with a second peak at 24 hours. Taking 100 mg 3 times a day caused an average level of 5.4 micrograms/ml, which may be up to 7 times higher than usual levels. CoQ10's half-life in blood is about 34 hours. Upon reaching the liver, CoQ10 is packaged into low-density lipoprotein and parts of cholesterol. CoQ10 is concentrated in tissues of the heart, liver, and kidneys. Oral CoQ10 is slowly absorbed through the intestine. Absorption can vary greatly depending on type of supplement. In a trial comparing different formulas, including combinations of polysorbate, lecithin, or soybean oil, results showed best absorption with the soybean-oil-and-CoQ10-only formula. CoQ10 supplements that contain vegetable oil or vitamin E absorb better than CoQ10 alone. CoQ10 is eliminated mainly through the bile system, with over 60% of an oral CoQ10 dose passing through unchanged in the stool. ROLE OF COQ10 IN HEART FAILURE Heart failure may include a state of reduced energy linked to low CoQ10 levels. Patients with severe CHF tend to have low levels of CoQ10, so patients with CHF may be more likely to benefit from CoQ10 supplements. Studies report benefits from short-term (1 to 4 weeks) and long-term (3 months to 6 years) oral CoQ10 use at 50 to 100 mg per day. The CoQ10 is added to standard drug therapy. Two trials studied more than 4,000 class 2 to class 4 CHF patients who improved in oxygen level, edema, lung congestion, shortness of breath, and palpitations on CoQ10. Results showed reduced symptoms as early as 2 weeks and still present at 4 weeks. Randomized, double-blind, placebo-controlled trials studying CoQ10 at 60 to 200 mg per day showed various benefits in CHF patients when added to standard CHF drugs. Eight of these 10 studies showed favorable effects with improved ejection fraction, heart output, and symptoms. Improved quality of life and reduced hospitalizations for heart failure were reported in some controlled studies. Two trials, however, did not show significant benefits. All studies used small numbers of patients, making conclusions about mortality hard to draw. COQ10 FOR ANGINA CoQ10 may improve exercise tolerance in patients with stable angina by protecting heart tissue from ischemia. This lets tissue reach higher energy use. Six small randomized, double-blind, placebo- controlled studies suggest that CoQ10 protects heart tissue from ischemia and reduces angina. All these studies showed that CoQ10 at doses of 60 to 600 mg per day increased exercise time and delayed onset of angina compared to placebo. COQ10 FOR HIGH BLOOD PRESSURE Patients with high blood pressure often have low CoQ10 levels. A pilot study showed that taking CoQ10 lowered both systolic and diastolic blood pressures. In high blood pressure trials, CoQ10 doses ranged from 30 to 360 mg per day. Results from these high blood pressure trials are not consistent. No one knows why CoQ10 supplements sometimes lower blood pressure. WHAT DOSE TO TAKE? CoQ10 is available in tablet or capsule form. Studies show that oil-based CoQ10 in a soft gelatin capsule is absorbed better than powder-based "solid" tablets. At least 100 mg per day in divided doses should be taken. For CHF, a CoQ10 supplement is added to standard drug therapy at 50 to 150 mg per day in 2 or 3 smaller doses. Considerable improvement in CHF patients may be seen 2 weeks to 3 months after starting CoQ10. In patients with stable angina, CoQ10 has been given at 150 to 600 mg per day. For high blood pressure, a single dose of 100 mg per day is suggested. SIDE EFFECTS CoQ10 does not cause any major side effects. The most common effects in trials were nausea, diarrhea, heartburn, and reduced appetite. However, these occurred in less than 1% of patients and usually go away with continued CoQ10 use. Doses over 300 mg per day can raise liver enzyme levels but no problems from this have been reported. CHF patients have been seen to get worse after stopping CoQ10, and then to get better again after restarting it. In one study, relapse occurred in 88% of patients after stopping the supplement but 75% improved again after resuming CoQ10. INTERACTIONS Several studies show that cholesterol-lowering drugs of the statin type lower CoQ10 blood levels. This includes simvastatin, pravastatin, and lovastatin. Other types of cholesterol-lowering drugs do not seem to affect CoQ10 levels. Oral anti-diabetic drugs like acetohexamide, glyburide, phenformin, and tolazamide lower CoQ10 blood levels. Reduced need for insulin has been seen in diabetics taking CoQ10 so extra blood sugar monitoring may be needed. Coenzyme Q10 is structurally related to vitamin K so theoretically it could encourage blood to clot more quickly. Several individual case reports (anecdotal only) describe CoQ10 lowering INR in warfarin (Coumadin) patients, with INR returning to previous levels after stopping CoQ10. This has not been proven in trials. Taking CoQ10 in patients with liver failure may greatly increase CoQ10 blood levels because CoQ10 is processed by the liver. CoQ10 use in these patients is not recommended. CONCLUSIONS Oral CoQ10 gives benefits in heart failure, angina, and high blood pressure patients. It is safe and well tolerated. However, published trials show inconsistent results. It is difficult to draw definite conclusions without further trials. A conservative approach is to use CoQ10 as an added treatment for CHF, but not for angina or high blood pressure. CoQ10's good effect on ejection fraction, exercise tolerance, and cardiac output have been shown in CHF patients. CoQ10 may benefit patients with classes 2 to 4 CHF. Patients with angina may see increased ability to exercise with CoQ10 use. Using CoQ10 for angina may be less cost-effective due to the higher doses required. However, CoQ10 in high blood pressure patients is not really justified until more trials are done.