Statin Side Effects

WELL-KNOWN SIDE EFFECTS: LIVER AND MUSCLE

The side effects that your doctor will be most familiar with are:

1. Liver: Changes in liver function occur in a small fraction of people; your doctor will probably monitor blood tests to check that your liver continues to function well.  If the liver function becomes too abnormal, your doctor will stop the drug.  The liver is expected to return to normal function.
2. Muscle: Muscle symptoms are common with statin drugs.  “Myopathy," involving actual damage to muscle tissue, can be very serious.  For this reason, if you develop new muscle pain, weakness, or tenderness on the drugs you should inform your doctor immediately.  Very rarely, if myopathy occurs and the drugs are not stopped, a very dangerous condition, called “rhabdomyolysis”, can occur that can sometimes be fatal.  Myopathy and rhabdomyolysis are more common if people are on other cholesterol lowering drugs, particularly niacin or gemfibrozil (or other “fibrates”), as well as a statin.  Certain other classes of drugs in combination with statins can also increase the risk of problems.

Things You Should Know 

If you develop muscle symptoms it is very important that you let your doctor know immediately; your doctor will probably draw a blood test called a “CK” (creatine kinase) test that assesses whether muscle damage is present.  CK is a muscle enzyme, and the test is also done during suspected heart attacks, to test for damage to the heart muscle.  It is important to be aware that normal levels of "CK" do not exclude a relation to statins.
If you get an infection and are put on antibiotics or antifungal agents, make sure the prescribing doctor knows you are on statins, because several antibiotics and antifungal drugs can interact with the statin drugs to cause problems.  In fact, it is a good idea with each new drug you are started on to be sure the doctor is familiar with the rest of your drug list.  Also, if you become seriously ill or are scheduled for surgery, you should talk to your doctor about stopping your statin drug until you are better, or well on the road to recovery.
You should be aware that grapefruit juice affects metabolism of most statins (but not pravastatin) and can markedly increase blood levels, so grapefruit juice may be best avoided while you are on statins.  This is not true for other citrus juices.

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LESSER-KNOWN SIDE EFFECTS

Memory, Thinking and Concentration

Some people report changes in memory, attention, or concentration on statins.  They may have trouble finding the right word; may forget tasks they started to do; and may have trouble following conversations. Some people describe "holes in their memory."  Some people worry that they are developing Alzheimer's. Of course, since people on statin drugs are often older, and may be experiencing age-related loss of memory, it makes it difficult to know whether the drugs are responsible.  Many people report improvement in memory and thinking when they stop the drug; or improvement if they go on a lower dose.  These findings suggest that the drug is responsible.

As of now there there are two randomized controlled trials that have looked at thinking on these drugs. One was published in May 2000 in the journal called American Journal of Medicine.  Dr. Matthew Muldoon, at the University of Pittsburgh, showed that statin drugs on average reduces “cognition,” that is to say, people who were on a statin drug did worse on tests of thinking and memory ability, even though they started out the same as those who were put on a placebo pill.  These effects were “significant” statistically.  On average the effects were considered to be small, but of course some people have no alteration, while others have bigger losses in memory and thinking.  A second study by Dr. Muldoon shared similar findings.  However, in another statin trial, no effect was seen on cognitive function.  That study, in persons over 70, was not expressly designed to assess the effect of statins on thinking, but it did assess cognitive function.

Depression and Irritability

Some people report changes in mood on statins.  These include loss of interest in activities and loss of interest in social involvement.  Some people report frank depression, but it is not known if these effects are more common in people on statins than in people who are not.  However, some people reliably become down when on the drugs, and better when off, so that for these people there appears to be a relationship.  It is possible that some people may also get a boost to their mood with low cholesterol, although this is less commonly reported.  In some cases violence, psychosis, and suicide have been reported.  We have published a small case series describing several instances of severe irritability arising on statins, resolving when statins were stopped, and returning when statin use was resumed.

Pain

Although muscle pain is a well-recognized side effect of these drugs (and one that should be reported, so tests can be done), other pain effects have been reported by many people on statins, but have not been studied extensively include headaches, joint pains, and abdominal pain.

Peripheral Neuropathy

Studies have confirmed that peripheral neuropathy (tingling and numbness or burning pain) may occur with statins.

Other Side Effects

Sleep problems, sexual function problems, fatigue, dizziness and a sense of detachment are also reported with these drugs.  Additionally, people have mentioned experiencing swelling, shortness of breath, vision changes, changes in temperature regulation, weight change, hunger, breast enlargement, blood sugar changes, dry skin, rashes, blood pressure changes, nausea, upset stomach, bleeding, and ringing in ears or other noises.

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