CPK (or CK) is creatine phosphokinase, an enzyme found mainly in the heart, brain, and skeletal muscle. It is tested by taking a blood sample.

High CPK can indicate muscle destruction, heart attacks, central nervous system issues, and others. Long term exposure of high CPK can load up your kidneys, and may cause muscle loss and weakness.

A CPK blood test is usually not included in usual lab work unless you ask for it. Sometimes we have no symptoms when CPK is high, but most of the time we have body aches and soreness. CPK can increase with exercise, but if you exercise frequently and you have baseline CPK info, your doctor can determine what CPK increase may be drug induced after you start a certain medication. 

To make sure your high CPK is not induced by heavy exercise, do not exercise for 4 days before getting the test.

Some medications can also increase CPK. Among them are amphotericin B, ampicillin, some anesthetics, blood thinners, aspirin, clofibrate, dexamethasone, furosemide, alcohol, and cocaine. HIV medications like Isentress and Selzentry have also been reported to increase CPK in some patients.

Low thyroid function can also be a cause of high CPK, so get it checked.

There is no treatment. If CPK gets really high, doctors try to switch you to another medication, but it is very difficult for some patients to switch since they have no other options.

Some doctors prescribe corticoid steroids to reduce whatever the inflammation may be, but this is not a cure. Corticoid steroids can lower bone density and testosterone, cause water retention and fat gain, and have been linked with joint bone death (necrosis), so they are not a good option to stay on for the long term.

If you are taking statins with or without fibrates, high CPK may indicate muscle related problems that these drugs can cause in some people. Statins (with or without fibrates) can cause rhabdomyolysis which can cause destruction of muscle tissue in few patients and increase CPK. Some patients have anecdotally reported improvements of this problem by taking Coenzyme Q-10 (statins lower it) and a good antioxidant formula.

Get the test here