A number of tricyclic antidepressants have been shown to inhibit enzymes that require coenzyme Q10 (CoQ10), a nutrient that is needed for normal heart function.¹⁴ It is therefore possible that CoQ10 deficiency may be a contributing factor to the cardiac side effects that sometimes occur with tricyclic antidepressants. Some practitioners advise patients taking tricyclic antidepressants to supplement with 30–100 mg of CoQ10 per day.

A number of tricyclic antidepressants have been shown to inhibit enzymes that require coenzyme Q10 (CoQ10), a nutrient that is needed for normal heart function.¹⁵ It is therefore possible that CoQ10 deficiency may be a contributing factor to the cardiac side effects that sometimes occur with tricyclic antidepressants. Some practitioners advise patients taking tricyclic antidepressants to supplement with 30–100 mg of CoQ10 per day.

In a group of patients beginning treatment with atorvastatin, the average concentration of coenzyme Q10 in blood plasma decreased within 14 days, and had fallen by approximately 50% after 30 days of treatment.¹⁶ In a preliminary study, supplementation with 100 mg of CoQ10 per day reduced the severity of muscle pain by 40% in people with muscle pain caused by a statin drug.¹⁷ Many doctors recommend that people taking HMG-CoA reductase inhibitor drugs such as atorvastatin also supplement with approximately 100 mg CoQ10 per day, although lower amounts, such as 10 to 30 mg per day, might conceivably be effective in preventing the decline in CoQ10 levels.

A number of tricyclic antidepressants have been shown to inhibit enzymes that require coenzyme Q10 (CoQ10), a nutrient that is needed for normal heart function.¹⁸ It is therefore possible that CoQ10 deficiency may be a contributing factor to the cardiac side effects that sometimes occur with tricyclic antidepressants. Some practitioners advise patients taking tricyclic antidepressants to supplement with 30–100 mg of CoQ10 per day.

A number of tricyclic antidepressants have been shown to inhibit enzymes that require coenzyme Q10 (CoQ10), a nutrient that is needed for normal heart function.¹⁹ It is therefore possible that CoQ10 deficiency may be a contributing factor to the cardiac side effects that sometimes occur with tricyclic antidepressants. Some practitioners advise patients taking tricyclic antidepressants to supplement with 30–100 mg of CoQ10 per day.

A number of tricyclic antidepressants have been shown to inhibit enzymes that require coenzyme Q10 (CoQ10), a nutrient that is needed for normal heart function.²⁰ It is therefore possible that CoQ10 deficiency may be a contributing factor to the cardiac side effects that sometimes occur with tricyclic antidepressants. Some practitioners advise patients taking tricyclic antidepressants to supplement with 30–100 mg of CoQ10 per day.

In a randomized, double-blind trial, blood levels of coenzyme Q10 (CoQ10) were measured in 45 people with high cholesterol treated with lovastatin or pravastatin (drugs related to fluvastatin) for 18 weeks.²³ A significant decline in blood levels of CoQ10 occurred with either drug. One study found that supplementation with 100 mg of CoQ10 prevented declines in CoQ10 when taken with simvastatin (another HMG-CoA reductase inhibitor drug).²⁴ Many doctors recommend that people taking HMG-CoA reductase inhibitor drugs such as fluvastatin also supplement with approximately 100 mg CoQ10 per day, although lower amounts, such as 10–30 mg per day, might conceivably be effective in preventing the decline in CoQ10 levels.

In a randomized study of 21 men with combined hyperlipidemia, ten to twelve weeks of gemfibrozil therapy reduced coenzyme Q10 blood levels to the levels seen in healthy men.²⁵ The clinical significance of this finding is unknown.

A number of tricyclic antidepressants have been shown to inhibit enzymes that require coenzyme Q10 (CoQ10), a nutrient that is needed for normal heart function.²⁶ It is therefore possible that CoQ10 deficiency may be a contributing factor to the cardiac side effects that sometimes occur with tricyclic antidepressants. Some practitioners advise patients taking tricyclic antidepressants to supplement with 30–100 mg of CoQ10 per day.

It has been clearly documented that HMG Co-A reductase inhibitors, including lovastatin,²⁷ deplete coenzyme Q10 (CoQ10) levels in the blood, an effect that may be responsible for other side effects of the drug, such as abnormal liver function. In a double-blind trial, blood levels of CoQ10 were measured in 45 people with high cholesterol treated with lovastatin (20–80 mg per day) or pravastatin (10–40 mg per day) for 18 weeks.²⁸ A significant decline in blood levels of CoQ10 occurred with both drugs. Supplementation with 90–100 mg per day CoQ10 has been shown to prevent reductions in blood levels of CoQ10 due to simvastatin.^{29 , 30} In a preliminary study, supplementation with 100 mg of CoQ10 per day reduced the severity of muscle pain by 40% in people with muscle pain caused by a statin drug.³¹

A number of tricyclic antidepressants have been shown to inhibit enzymes that require coenzyme Q10 (CoQ10), a nutrient that is needed for normal heart function.³² It is therefore possible that CoQ10 deficiency may be a contributing factor to the cardiac side effects that sometimes occur with tricyclic antidepressants. Some practitioners advise patients taking tricyclic antidepressants to supplement with 30–100 mg of CoQ10 per day.

A number of tricyclic antidepressants have been shown to inhibit enzymes that require coenzyme Q10 (CoQ10), a nutrient that is needed for normal heart function.³⁵ It is therefore possible that CoQ10 deficiency may be a contributing factor to the cardiac side effects that sometimes occur with tricyclic antidepressants. Some practitioners advise patients taking tricyclic antidepressants to supplement with 30–100 mg of CoQ10 per day.

In a randomized, double-blind trial, blood levels of coenzyme Q10 (CoQ10) were measured in 45 people with high cholesterol treated with lovastatin or pravastatin (drugs related to fluvastatin) for 18 weeks.³⁶ A significant decline in blood levels of CoQ10 occurred with either drug. One study found that supplementation with 100 mg of CoQ10 prevented declines in CoQ10 when taken with simvastatin (another HMG-CoA reductase inhibitor drug).³⁷ Many doctors recommend that people taking HMG-CoA reductase inhibitor drugs such as fluvastatin also supplement with approximately 100 mg CoQ10 per day, although lower amounts, such as 10–30 mg per day, might conceivably be effective in preventing the decline in CoQ10 levels.

A number of tricyclic antidepressants have been shown to inhibit enzymes that require coenzyme Q10 (CoQ10), a nutrient that is needed for normal heart function.⁴⁰ It is therefore possible that CoQ10 deficiency may be a contributing factor to the cardiac side effects that sometimes occur with tricyclic antidepressants. Some practitioners advise patients taking tricyclic antidepressants to supplement with 30–100 mg of CoQ10 per day.

Pretreating people with the antioxidant coenzyme Q10 before administration of doxorubicin has reduced cardiac toxicity²¹ —an action also reported in animals.²² Some doctors recommend 100 mg per day.

Phenothiazine drugs similar to perphenazine can cause changes in heart activity in some people, which might be prevented by supplementing with coenzyme Q10.^{33 , 34} Therefore, some health practitioners may recommend coenzyme Q10 supplementation to people taking perphenazine.

Phenothiazine drugs like thioridazine can cause changes in heart activity in some people, which might be prevented with coenzyme Q10 supplementation.³⁸ Therefore, some doctors and pharmacists may recommend coenzyme Q10 supplements to individuals taking thioridazine.

In a group of 16 glaucoma patients treated with a timolol eye preparation, six weeks of oral coenzyme Q10 (90 mg per day) was reported to reduce timolol-induced cardiovascular side effects without affecting intraocular pressure treatment.³⁹

Coenzyme Q10 (CoQ10) is structurally similar to vitamin K and may affect blood coagulation.⁴¹ Four case reports describe possible interference by CoQ10 with warfarin activity.^{42 , 43 , 44} It remains unknown how common or rare this interaction is. Those taking warfarin should only take CoQ10 with the guidance of their doctor.

In double-blind trials, treatment with pravastatin and other HMG-CoA reductase inhibitors has resulted in depleted blood levels of coenzyme Q10 (CoQ10).^{45 , 46} Supplementation with 90–100 mg CoQ10 per day has been shown to prevent reductions in blood levels of CoQ10 due to simvastatin, another drug in the same category as pravastatin.^{47 , 48} In a preliminary study, supplementation with 100 mg of CoQ10 per day reduced the severity of muscle pain by 40% in people with muscle pain caused by a statin drug.⁴⁹

Propranolol inhibits enzymes dependent on coenzyme Q10 (CoQ10). In one trial, propranolol-induced symptoms were reduced in people given 60 mg of CoQ10 per day.⁵⁰

In patients with high cholesterol, simvastatin therapy results in decreased serum coenzyme Q10 (CoQ10) levels.^{51 , 52} Several trials, including double-blind trials, have confirmed this effect of simvastatin and other HMG-CoA reductase inhibitors, such as lovastatin and pravastatin.^{53 , 54 , 55} Supplementation with 100 mg per day or 10 mg three times daily of CoQ10 has been shown to prevent reductions in blood levels of CoQ10 due to simvastatin.^{56 , 57} In the latter study, people taking CoQ10 along with simvastatin increased their blood CoQ10 concentration by 63%. In a preliminary study, supplementing with 100 mg of CoQ10 per day reduced the severity of muscle pain by 40% in people with muscle pain caused by a statin drug.⁵⁸ However, in a double-blind trial, supplementation with 200 mg of CoQ10 per day did not improve muscle symptoms or tolerance to simvastatin.⁵⁹ Because low CoQ10 levels are undesirable in people who have or are at risk for developing heart disease, many doctors recommend that people taking HMG-CoA reductase inhibitor drugs such as simvastatin also supplement with approximately 100 mg CoQ10 per day, although lower amounts, such as 10 to 30 mg per day might conceivably be effective in preventing the decline in CoQ10 levels.