Various trials have confirmed the efficacy of CoQ10 leading to significant improvement in clinical and haemodynamic parameters and exercise tolerance in patients. In this write-up, Dr. Sundeep Mishra focusses on the use of CoQ10 in heart failure, statin intolerance, and hypertension.

Coenzyme Q10 (CoQ10) a.k.a ubiquinone is a mitochondrial coenzyme which is essential for the production of ATP. Being at the core of cellular energetic it is especially important in cells with high energy requirements like the cardiac cells. In addition, it has an antioxidant, a free radical scavenging and a vasodilator effect which may be helpful in cardiac cellular patho-physiology.

In particular, it inhibits LDL oxidation, thus impacting on the progression of atherosclerosis. Furthermore, it decreases pro-inflammatory cytokines and decreases blood viscosity and also improves ischaemia and reperfusion injury following coronary revascularisation.

Many cardiac disease states may contribute to CoQ10 deficiency. Some examples are patients with heart failure and those on statin and beta-blocker therapy. Statins have been found to decrease CoQ10 levels by inhibiting the mevalonate pathway and beta-blockers by blocking myocardial enzymes.

Heart Failure

A number of controlled pilot trials with supplemental CoQ10 in heart failure have revealed improvement in ATP synthesis, left ventricular function parameters such as ejection fraction, stroke volume, and cardiac output, as well as symptoms and exercise parameters without significant side effects.

Subsequent meta-analyses have confirmed these findings, although the magnitude of benefit tends to be less notable in patients with severe heart failure, or within the context of ACE inhibitor therapy. A multicentre randomised placebo-controlled Q-SYMBIO trial which assessed the impact of supplemental CoQ10 on hard endpoints in CHF enrolled 420 patients receiving either CoQ10 (100 mg three times daily) or placebo and followed them for 2 years.

It revealed that while CoQ10 therapy had no impact on short-term functional parameters, it led to significant reduction in the primary long-term endpoint i.e. MACE (which was observed in 15% of CoQ10 group versus 26% in placebo group): HR=0.50, CI 0.32 to 0.80, p=0.003. Thus in view of excellent tolerance, reasonable efficacy and relative affordability, CoQ10 therapy has emerged as an attractive option in the management of CHF at least in no-option group.

Statin intolerance

Statins are amongst the most widely prescribed medication in cardiac practice, however, statin intolerance especially of high dose represents a major limitation of this therapy. From 1990 to 2004, 13 controlled trials demonstrated significant CoQ10 depletion secondary to statin therapy. Thus CoQ10 supplementation is the most popular therapy for statin myalgia among both physicians and patients.

However, clinical evidence supporting the use of Coenzyme Q 10 is limited and more controversial with four trials showing benefit and three showing no effect. Furthermore, a recent meta-analysis of 5 studies enrolling 253 participants found no CoQ10 effect on muscle pain despite a trend toward a decrease in symptoms. Another lead-in, double-blind, placebo controlled trial of statin vs. placebo found no impact on muscle pain, muscle strength, or aerobic exercise capacity.

Hypertension

CoQ10 might enhance the effectiveness of certain blood pressure medications and even directly lower blood pressure by its vasodilator effect. A recent meta-analysis of clinical trials investigated the use of CoQ10 as per its anti-hypertensive efficacy.

Blood pressure reduction was noted in all 12 trials, regardless of whether CoQ10 was given alone or as an adjunct to standard antihypertensive medication, without significant side effects. Thus, in some cases, it does seem reasonable to recommend this therapy as an adjunct to conventional antihypertensive therapy. However, the real value of this therapy can only be ascertained by a larger, well-designed clinical trial of CoQ10's antihypertensive effects with specific clinical end-points such as the risk of stroke or myocardial infarction.

Downside of Coenzyme Q 10

1. CoQ10 can reduce the efficacy of Warfarin and increase the risk of thrombosis but its anti-platelet effects may complement those of aspirin, increasing the risk of bleeding.
2. It may lower blood sugar levels, and it should be monitored in patients with diabetes or patients taking medications or supplements that are known to lower blood sugar.
3. Finally, gastrointestinal effects such as abdominal discomfort, nausea, vomiting, diarrhea, and anorexia and headache and rashes have also been noted.

Disclaimer- The views and opinions expressed in this article are those of the author's and do not necessarily reflect the official policy or position of M3 India.

The writer, Dr. Sundeep Mishra is a Professor of Cardiology.