Coenzyme Q10
Medicinal Uses, Interactions, Side Effects, Dosage
By Steve Mathew
Coenzyme Q10 is known by a variety of names, including CoQ, CoQ10, and ubiquinone.
It is found in the mitochondria of many organ tissues such as the heart, kidney, and liver.
The name coenzyme Q10 refers to the coenzyme Q enzyme containing 10 isoprenoid subunits.
The reduced form of coenzyme Q10 is called ubiquinol and this form predominates in the
systemic circulation. Most supplement companies obtain CoQ10 from plant sources.
Chemical structure of Ubiquinone (Coenzyme Q)
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Uses and Benefits:
CoQ10 has antioxidant properties, and it has been used primarily for cardiovascular
conditions such as congestive heart failure (CHF), hypertension, ischemic heart disease,
and cardiomyopathies. It is also used as a general antioxidant supplement.
Pharmacology:
CoQ10 has been described as one of the most metabolically active molecules present
in the body. It circulates in the blood in the reduced form, ubiquinol, and is involved
in many cell processes (mitochondrial electron transport) and in the generation of adenosyl
triphosphate (ATP), which powers processes that create energy.1 It serves as an endogenous
antioxidant, scavenging free radicals. CoQ10 may also have a protective action on cell membranes
by inhibiting the action of phospholipase A 2 ·2 All of these actions suggest that it has an
important role in vital processes, including cardiac muscle performance. CoQ10 is structurally
similar to menaquinone, also known as vitamin K 2 .
Clinical Trials:
Hypertension - In various clinical trials (open label and controlled studies), mostly
published by the same research group,
CoQ10 significantly decreases blood pressure in with mild-moderate hypertension. Statistically
significant reductions in systolic and diastolic blood pressures (10 mmHg) were observed after
10 weeks; however, these studies lacked a placebo comparison group. One
randomized, double-blind, comparative trial and one randomized, placebo-controlled, crossover
trial have suggested similar reductions in systolic and diastolic blood pressures. In one of
these trials, a reduction in systolic and diastolic blood pressure (7-10 I nmHg) was observed
after 8-10 weeks of CoQ1 a therapy compared to placebo. These latter studies, however, suffer
from inadaquate treatment allocation and a lack of statistical power to detect differences.
Thus, the clinical evidence for CoQ1 a's value in hypertension is inadequate.
Congestive Heart Failure - Older studies suggested that CoQ10 was effective as adjunctive
therapy in the treatment of CHF. A meta-analysis of eight clinical trials concluded that,
while more evidence was required, CoQ10 could playa useful role in the management of this
condition. Many of the clinical trials included in the meta-analysis lacked control groups,
and used crude estimates of heart muscle function. Two recent, wellconducted clinical trials
used objective assessments of heart muscle function in patients with CHF. One was a randomized,
double-blind, placebo-controlled trial and the other was a randomized, double-blind, placebo
controlled, crossover trial. In patients with CHF (NYHA III and IV), CoQ10, at a dose of
100-200 mg daily for 3-6 months, was not significantly more effective than placebo. These
trials used Swan-Ganz measurements as well as echocardiography to assess left ventricular
function.
Ischemic Heart Disease - Results from two randomized, double-blind, placebo-controlled
trials found that CoQ1 a supplementation improved a number of clinical measures in patients
diagnosed with chronic stable angina or coronary artery disease, and in those patients who
had a history of acute myocardial infarction. These trials suggest improvements in the
markers for atherosclerosis (lipoprotein (a) and HDL-cholesterol); in exercise tolerance
and in delaying the time to develop ischemic changes on electrocardiograph (ECG) tracings.
Other improvements include a reduction in cardiac deaths and rate of reinfarction in those
recovering from acute myocardial infarction, compared to placebo. This trial suggests that
the relative risk reduction of
sudden cardiac death with CoQ10 is 27%; however, the absolute risk reduction of sudden
cardiac death when compared to placebo is only 1.5%, suggesting a very small improvement
in risk with CoQ10. Furthermore, these trials were of short duration (1 month), and
clinical reliability is unknown.
Cardiomyopathy - Two small crossover trials that were randomized, double-blind,
and placebo-controlled assessed the effects of CoQ10 on moderate to severe
cardiomyopathy. In one trial, 25 patients with NYHA class I, II, and III received
CoQ10 (100 mg daily) or placebo. At the end of 4 months, no statistically significant
differences were observed in ventricular function, ejection fraction, and calculated
cardiac output. Additionally, no improvements in exercise tolerance or ECG tracings
were observed. In the second trial, in 19 patients diagnosed with NYHA class 1/1 or IV
cardiomyopathy, CoQ10 supplementation (100 mg daily) significantly improved cardiac
function. 16 However, this study failed to account for any carry-over of effects in
the crossover design.
Adverse Effects:
CoQ10 is well tolerated. In clinical trials, nausea, anorexia, and gastrointestinal
upset have rarely been reported. Some patients have experienced maculopapular rash and
thrombocytopenia. Other rare side effects include irritability, headache, and dizziness.
Side Effects and Interactions:
A decrease in endogenous levels of CoQ10 has been observed following administration of
HMG-CoA reductase inhibitors. The clinical significance of this effect is unknown.
Patients beginning statin therapy should not require CoQ10 supplementation, as the
benefits of statin therapy likely outweigh any potential risk associated with low
CoQ10 levels. Given the chemical similarity between vitamin K and CoQ10, the potential
exists for an interaction with warfarin. CoQ10 has decreased the effects of warfarin in
various case reports. Until more is known, CoQ10 should be used with caution or not at
all in patients receiving warfarin therapy.
Cautions:
In vitro studies suggested that CoQ10 may interfere with glucose regulation.
Randomized placebo-controlled trials in diabetics, however, have shown no effect
on blood glucose or metabolic control. Safety in pregnancy and lactation has yet to
be determined.
Preparations & Doses:
A minimum of 30 mg daily appears to be necessary to increase blood levels. The clinical
significance of increasing blood levels is unknown. For cardiac indications, typical
doses are 100-150 mg daily in 2 or 3 divided doses. These doses increase baseline CoQ10
levels to 2-3 mcg/ml (normal in adults is 0.7-1 mcg/ml).
Summary Evaluation:
The value of CoQ1 0 shows promise in adequately controlled trials ,of ischemic heart
disease, although trials are limited. Clinical for other cardiovascular disorders
(heart failure, cardiomypathy, and hypertension) are inadequate or provide mixed ,
and do not currently support the use of CoQ10 for these indications. CoQ10 does
have antioxidant activity, but the clinical significance of this effect is unknown.
Steve Mathew is a writer, who writes many great articles on herbal medicines and
ayurvedic medicines for common ailments and diseases. Visit us for more information
on herbal remediesand ayurvedic medicines.
http://www.health-care-tips.org/herbal-medicines
http://www.home-remedies.info/herbal-remedies
http://www.ayurvedic-medicines.org/
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