How Safe Is a Combination of Simvastatin and Fenofibrate?

Simvastatin and fenofibrate are drugs used to treat and improve blood cholesterol and triglyceride levels. For otherwise healthy people, simvastatin and fenofibrate can typically be combined safely, with little risk of harmful drug interactions. In most cases, however, just one of these drugs is sufficient to return cholesterol levels to normal, and combining them is not typically done.

Fenofibrate is a member of a class of drugs called antilipemic agents. These drugs increase the rate at which the body removed cholesterol from the blood. This is done selectively, and in fact fenofibrate can not only reduce levels of harmful low-density lipoprotein (LDL), it also increases levels of beneficial high-density lipoprotein (HDL). In addition, this drug reduces blood triglyceride levels. This medication is safe for most people, but can have toxic effects in people with liver or kidney disease. In addition it is not recommended for pregnant or nursing women.

Simvastatin is also a cholesterol-reducing medication, but it reduces cholesterol via a different mechanism than fenofibrate. This medication is one of a type called HMG CoA reductase inhibitors, more commonly known as statins. Most statins, including simvastatin, reduce blood levels of LDL cholesterol and triglycerides while also increasing levels of HDL cholesterol. Simvastatin can be unsafe for people with kidney or liver disease, diabetes, or a thyroid disorder, but is safe for most others.

Normally a doctor prescribes either one of these medications, but does not prescribe both for a single patient. Simvastatin and fenofibrate work in different ways to modify blood cholesterol levels, so if a person doesn’t respond well to antilipemic agents such as fenofibrate, her doctor might prescribe simvastatin or another statin medication instead. It is generally considered safe to use both simvastatin and fenofibrate at the same time, as long as the recommended doses are taken, and as long as the person is in good health overall. Someone who has liver or kidney disease might experience harmful side effects if both drugs are taken, however. Even though it is safe to combine the drugs, it is most common for a doctor to only prescribe a statin or an antilipemic agent.

A small number of clinical trials suggest that not only is a combination of simvastatin and fenofibrate safe for most people, it might even be beneficial. In two studies published in 2004 and 2005, people treated with a combination of the two drugs achieved healthier blood cholesterol levels than people treated with just one of the drugs, indicating that combined treatment could prove effective. These drugs can only be safely combined in people with normal liver and kidney function, however, as toxicity can result if the health of either organ is compromised.