Chaparral, Comfrey, and Coltsfoot

Possible Harmful Interaction

The herb chaparral ( Larrea tridentate or L. mexicana ) has been promoted for use in arthritis, cancer, and various other conditions, but there is insufficient evidence supporting its effectiveness. There are, however, concerns about its apparent liver toxicity.

Several cases of chaparral-induced liver damage have been reported, some of them severe enough to require liver transplantation. 1-6

Based on these reports, combining chaparral with other agents that are hard on the liver, such as statin drugs, may amplify the risk of potential liver problems. 7 Other herbs that are toxic to the liver include comfrey (Symphytum officinale) and coltsfoot (Tussilago farfara) .

Chinese Skullcap ( Scutellaria baicalensis )

Possible Harmful Interaction

The herb Chinese skullcap contains the substance baicalin as one of its presumed major active ingredients. One study found evidence that consumption of baicalin might lower blood levels of statin drugs. 34

St. John's Wort

Possible Harmful Interaction

The herb St. John’s wort, used to treat depression, may decrease blood levels of various drugs in the statin family, including simvastatin, lovastatin, and atorvastatin (but possibly not pravastatin). 22 One study documented that when people taking atorvastatin for high cholesterol additionally took St. John’s wort, cholesterol levels promptly rose. 33

Grapefruit Juice

Possible Harmful Interaction

Grapefruit juice impairs the body's normal breakdown of several drugs, including statins, allowing them to build up to potentially excessive levels in the blood. 8 A recent study indicates that this effect can last for 3 days or more following the last glass of juice. 9

Because this could increase the risk of serious drug side effects, if you take interacting statins, the safest approach is to avoid grapefruit juice altogether. Grapefruit juice may not affect fluvastatin or pravastatin because these drugs are broken down differently than other statins. 10

Vitamin B 3

Possible Benefits and Risks

Niacin (nicotinic acid) is vitamin B ₃ . In high doses (often 1,500 mg daily or more), niacin is effective in lowering cholesterol levels. Its other form, niacinamide (nicotinamide), does not affect cholesterol.

Combining high-dose niacin with statin drugs further improves cholesterol profile by raising HDL (“good”) cholesterol. 23,24,25 Unfortunately, there are real concerns that this combination therapy could cause a potentially fatal condition of muscle breakdown called rhabdomyolysis.

A growing body of evidence, however, suggests that the risk is relatively slight in individuals with healthy kidneys. Furthermore, even much lower doses of niacin than the usual dose given to improve cholesterol levels (100 mg versus 1,000 mg or more) may provide a similar benefit. 26 At this dose, the risk of rhabdomyolysis should be decreased. Nonetheless, it is not safe to try this combination except under close physician supervision.

Pomegranate

Possible Harmful Interaction

One case report suggests that consumption of pomegranate juice might increase the risk of rhabdomyolosis with rosuvastatin (Crestor). 28

Red Yeast Rice

Possible Harmful Interaction

Red yeast rice is an herbal cholesterol-lowering therapy. It contains a mixture of statins; its primary statin ingredient is lovastatin, making it most closely resemble the prescription drug Mevacor.

Based on the similarity of red yeast rice to statin drugs, the two should not be combined without medical supervision.

Coenzyme Q 10 (CoQ 10 )

Supplementation Possibly Helpful

Coenzyme Q ₁₀ (CoQ ₁₀ ) is a vitamin-like substance that plays a fundamental role in the body's energy production 13,14 and appears to be important for normal heart function. 15

Statin drugs inhibit the enzyme necessary for the body's synthesis of both cholesterol and CoQ ₁₀ , and as an inevitable part of their mechanism of action, reduce CoQ ₁₀ levels in the body. 16-18 Since these drugs are used to protect the heart, and since CoQ ₁₀ deficiency could in theory impair heart function, it has been suggested that this side effect may work against the intended purpose of taking statins. Furthermore, one might naturally hypothesize that some of the side effects of statins could be caused by this induced CoQ ₁₀ deficiency. Taking CoQ ₁₀ supplements does prevent the lowering of CoQ ₁₀ levels caused by statin drugs and accomplishes this without interfering with their therapeutic effects. 20 However, studies designed to determine whether the use of CoQ ₁₀ supplements actually offers any benefit to people taking statins have returned inconsistent results at best. 27,30-32,36 The most recent of these studies, for example, a relatively large double-blind, placebo-controlled trial of 44 people, failed to find that use of CoQ ₁₀ at a dose of 200 mg daily reduced the side effects of simvastatin. 36

Fish Oil

Supplementation Probably Helpful

Three double-blind, placebo-controlled studies suggest that combining adding fish oil (or its constituent DHA) with statin drugs may result in additional improvement in lipid profile. 21,29,35