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.
EVIDENCE OF EFFECTIVENESS IN HYPERTENSION
Rosenfeldt et al28 performed a meta-analysis and found that some trials documented statistically significant reductions in diastolic or systolic blood pressure or both, while others reported negligible effects.3,29 In one small trial,30 blood pressures actually went up in patients taking coenzyme Q10. Coenzyme Q10 dosages and length of therapy varied from study to study in the meta-analysis. Only minor adverse effects such as gastrointestinal upset and headache were reported.
Yamagami et al3 randomly assigned 20 patients with hypertension and a low coenzyme Q10 level to receive 100 mg of coenzyme Q10 or placebo daily for 12 weeks. Patients continued their usual antihypertensive regimen during the study period. Blood pressures, coenzyme Q10 levels, and antihypertensive drugs used were comparable between the study groups.
After 12 weeks of therapy, the mean coenzyme Q10 level in the active-treatment group had more than doubled, from 0.704 to 1.597 μg/mL. This group also experienced a statistically significant drop in systolic blood pressure, from 167 mm Hg at baseline to 148 mm Hg at 12 weeks. In the placebo group, the systolic blood pressure was 168 mm Hg at baseline and 164 mm Hg at 12 weeks; the change was not statistically significant. Diastolic pressure was not significantly lower at 12 weeks than at baseline in either group.
The authors concluded that coenzyme Q10 supplementation brought a mild reduction in high blood pressure in patients who had low coenzyme Q10 serum levels.
Digiesi et al31 randomized 18 patients with essential hypertension to receive either coenzyme Q10 100 mg or placebo daily for 10 weeks. All antihypertensive therapy was discontinued at baseline. After the first 10 weeks, patients went through a 2-week washout period and then were switched to the opposite therapy for an additional 10 weeks. Mean baseline blood pressure values were 167 mm Hg systolic and 103 mm Hg diastolic.
Those taking the supplement had a statistically significant decrease in systolic and diastolic pressures (P < .001). The antihypertensive effect was noted in the 3rd or 4th week of active treatment and persisted for the duration of therapy. The effects dissipated 7 to 10 days after coenzyme Q10 was stopped.
Langsjoen et al5 evaluated the effects of adding coenzyme Q10 to the antihypertensive drug regimen of 109 patients who had a primary diagnosis of essential hypertension in a prospective observational study. Patients with hypertension as a secondary diagnosis and other cardiovascular diseases were excluded. Variable doses of coenzyme Q10 were given, adjusted according to clinical response and to achieve serum levels greater than 2.0 μg/mL. The average dose was 225 mg/day; the mean serum level attained was 3.02 μg/mL.
Over several months, patients taking the supplement had a reduction in mean systolic pressure from 159 mm Hg at baseline to 147 mm Hg (P < .001), and a reduction in mean diastolic pressure from 94 to 85 mm Hg (P < .001). Thirty-seven percent of patients were able to discontinue one antihypertensive drug, 11% discontinued two drugs, and 4% were able to stop taking three drugs. However, 46% remained on the same antihypertensive regimen, and 3% needed an additional drug.
Singh et al6 randomized 64 patients who had coronary artery disease and who had been on antihypertensive drugs for more than 1 year to receive either B-complex vitamins or coenzyme Q10 (hydrosoluble Q-Gel) 60 mg orally once daily for 8 weeks. Five patients were not available for follow-up; therefore, only 59 patients were evaluated. Fifty-five (93%) of the 59 patients were taking only one antihypertensive drug. Initial antihypertensive drug use was similar between study groups and was continued throughout the trial.
After 8 weeks of therapy, the coenzyme Q10 group had significantly lower systolic and diastolic blood pressure than the placebo group (P < .05 for both). There was also a statistically significant decrease in the dosage of antihypertensive drugs in the coenzyme Q10 group but not in the placebo group (P < .05), reflecting coenzyme Q10’s additive antihypertensive effect.
Burke et al7 randomized 41 men and 35 women with isolated systolic hypertension (systolic pressure 150–170 mm Hg, diastolic pressure < 90 mm Hg) to receive a twice-daily dose of 60 mg of emulsified coenzyme Q10 (hydrosoluble Q-Gel) with 150 IU of vitamin E or placebo containing vitamin E alone for 12 weeks. The study also included 5 men and 4 women with normal blood pressure, all of whom received coenzyme Q10. A total of 80 patients completed treatment. The primary goal of the study was to determine the efficacy of coenzyme Q10 in the treatment of isolated systolic hypertension in patients without comorbid conditions. Blood pressures were monitored twice a week during the trial, by the same nurse.
After 12 weeks of treatment, the mean reduction in systolic pressure in hypertensive patients on coenzyme Q10 was 17.8 ± 7.3 mm Hg. There were no significant changes in diastolic pressure in any study group with treatment. Patients with isolated systolic hypertension who were taking coenzyme Q10 had a statistically significant reduction in systolic pressure compared with baseline and placebo (P < .01 for both). Approximately 55% of patients on coenzyme Q10 achieved a reduction in systolic pressure of 4 mm Hg or greater, while 45% did not respond to therapy. The mean plasma coenzyme Q10 level of the treatment group increased from 0.47 ± 0.19 μg/mL to 2.69 ± 0.54 μg/mL after 12 weeks; however, the study did not have the statistical power to demonstrate a relationship between coenzyme Q10 levels and changes in blood pressure. Twenty-seven (34%) of the 80 patients were taking a statin while on coenzyme Q10 therapy.
