Coenzyme Q10: A therapy for hypertension and statin-induced myalgia?
ABSTRACTSome small clinical trials seem to show that coenzyme Q10 supplements can be used to lower blood pressure and to treat or prevent myalgia caused by hydroxymethylglutaryl coenzyme A reductase inhibitors (statins). However, larger trials are needed to determine if they are truly effective for these purposes. The authors examine the evidence and also discuss issues such as bioavailability, elimination, safety, and cost.
KEY POINTS
- In some clinical trials, coenzyme Q10 supplements significantly lowered diastolic and systolic blood pressure.
- Statins may lower coenzyme Q10 serum levels, and some investigators have evaluated the relationship between coenzyme Q10 deficiency and statin-related myalgia, but more evidence is needed to support the use of coenzyme Q10 supplements to prevent or treat myalgia.
- Coenzyme Q10 supplementation appears to be relatively safe. Most clinical trials have not reported significant side effects that necessitated stopping therapy. Gastrointestinal effects include abdominal discomfort, nausea, vomiting, diarrhea, and anorexia. Allergic rash and headache have also been reported.
SLOWLY ELIMINATED
Taken orally, coenzyme Q10 has a low clearance rate, with an elimination half-life of about 34 hours.39
After absorption, exogenous coenzyme Q10 is taken up by chylomicrons that transport it to the liver, where it is incorporated into verylow-density lipoproteins. It is then distributed to various organs, including the adrenal glands, spleen, kidneys, lungs, and heart. Coenzyme Q10 is eliminated primarily via the biliary tract. About 60% of an oral dose is eliminated in the feces during chronic oral administration.39
TWICE-DAILY DOSING
A typical daily dose of coenzyme Q10 for treating hypertension is 120 to 200 mg, usually given orally in two divided doses.1 For statininduced myopathy, 100 to 200 mg orally daily has been used.1
Coenzyme Q10 is given in divided doses to enhance its absorption and to minimize gastrointestinal effects.1,43 Taking it with a fatty meal may also increase its absorption.43
Since solubilized forms of coenzyme Q10 and ubiquinol have significantly greater bioavailability than nonsolubilized forms, the therapeutic dose of these formulations may be lower.47
MONITORING DURING TREATMENT
Without supplementation, the mean serum level of endogenous coenzyme Q10 has been reported to be 0.99 ± 0.30 mg/L (range 0.55– 1.87).18 Serum levels above 2 μg/mL have been associated with significant reductions in blood pressure.5,7,28
The possible effects of coenzyme Q10 on blood pressure, blood glucose levels, serum creatine kinase levels, and myopathic symptoms should be kept in mind when monitoring patients who have hypertension,41 diabetes,41,42 or statin-induced myalgia.15,17 Coenzyme Q10’s possible potentiating effects on antiplatelet drugs and its inhibitory effect on warfarin should be kept in mind as well.
COST VARIES
Coenzyme Q10 is available in different dosage forms (eg, regular and rapid-release softgel capsules, regular and chewable tablets, chewable wafers, and liquid) from a variety of manufacturers. Products come in different strengths, typically ranging from 30 to 400 mg. USP-verified formulations are listed at www.usp.org/USPVerified/dietarySupplements/under “Verified Supplements.” Only USP-verified products that claim to be water-soluble meet USP dissolution requirements.
The cost varies, depending on the vendor. In general, dosage forms with greater bioavailability, such as Q-Gel and ubiquinol supplements, are more expensive. For example, a regimen of 60 mg twice daily of regular-release coenzyme Q capsules may cost approximately $20 per month, compared with $60 per month for the same supply of Q-Gel Ultra capsules. However, in some cases, supplements that produce higher serum levels may be more cost-effective.
CURRENT ROLE IN THERAPY
As an antihypertensive adjunct
Several small clinical trials have shown that coenzyme Q10 supplementation can lower blood pressure. The supplements were reported to be safe and well tolerated. Moreover, some patients with essential hypertension who were taking coenzyme Q10 were able to discontinue one or more antihypertensive drugs. A significant reduction in blood pressure with use of coenzyme Q10 would be expected to reduce the adverse consequences of hypertension in the same manner as conventional antihypertensive agents.
However, no large, double-blind, randomized study has evaluated the impact of coenzyme Q10 when taken with other antihypertensive drugs (eg, angiotensin-converting enzyme inhibitors, beta-blockers, diuretics) on specific clinical end points such as the incidence of stroke or death from a major cardiac event. Furthermore, its effects on cardiac function, exercise tolerance, and quality of life have not been determined.
The bottom line. In some cases, it seems reasonable to recommend this product as an adjunct to conventional antihypertensive therapy. Larger, well-designed clinical trials of coenzyme Q10’s antihypertensive effects on specific clinical end points such as the risk of stroke or myocardial infarction are needed to define its true therapeutic value.
As a treatment for statin-induced myalgia
Clinical evidence supporting coenzyme Q10’s use in the treatment of statin-induced myopathy is limited. Whether coenzyme Q10 is depleted from muscle tissue during statin therapy has not been confirmed. Supplementation helped reduce the severity of musculoskeletal effects of megadoses of lovastatin. However, clinical trials of coenzyme Q10 in the treatment of myalgia associated with antilipidemic statin doses did not consistently report significant improvement. Nevertheless, coenzyme Q10 has been shown to be relatively safe, with few adverse effects.
The bottom line. In some cases, coenzyme Q could be considered as a possible treatment for statin-induced myalgia, pending large-scale studies to determine if it is truly effective for this purpose.
