Statin medications lower “bad” cholesterol and help ward off heart disease. But the drugs may also have other wide-ranging and sometimes negative effects on the body. That doesn’t make statins unique: Any medication entering the bloodstream can affect different body systems. Nor does it mean that worry about side effects should stop you from taking a needed prescription.
However, being aware of the potential for side effects can help you spot any issues early. Then, if necessary, you can talk to your doctor about changing your statin dose or switching to a different medication.
A recent review by researchers from the Johns Hopkins Ciccarone Center for the Prevention of Heart Disease evaluated the evidence on non-cardiovascular harms and benefits associated with the use of statins. The researchers examined results from randomized controlled trials and systematic reviews published between 1994 and 2014. Here’s what their findings, published in BMJ in 2015, determined about the risks associated with taking statins.
1. Muscle pain
Muscle-related problems are probably the best-known side effect of statins. In studies, anywhere from 5 percent to more than 20 percent of statin users report myopathy—a general term for muscle disorders. Most often, people complain of aches and pain, muscle weakness, or nighttime cramps.
Rarely have statin users experienced a serious condition called rhabdomyolysis—a breakdown of muscle fibers that can lead to permanent kidney damage. Besides muscle symptoms, rhabdomyolysis may cause urine to appear red or cola-colored as muscle proteins are excreted from the body.
It’s not clear why statins affect muscle, but it’s possible the drugs can lower a natural substance called coenzyme Q, which helps muscle cells use energy. However, muscle problems appear largely confined to high-dose statins, particularly 80 mg doses of simvastatin (which are no longer recommended).
Another side effect, type 2 diabetes, arises when the body can no longer properly use the hormone insulin. There is evidence that statins can reduce the body’s insulin production or its sensitivity to the hormone.
Fortunately, the risk seems small. An analysis of 13 studies found that 4.9 percent of statin users developed diabetes over four years, versus 4.5 percent of participants given placebo pills. The risk is also largely seen in people who already have risk factors for diabetes, such as obesity or chronically high blood sugar.
The best way to protect yourself is to have your blood sugar checked as recommended by your doctor, further improve your dietary and exercise habits, and lower your weight about 5 pounds or more if you are overweight.
3. Memory loss
Since 2012, statin labels have included a warning about the possibility of “ill-defined memory loss” and “confusion.” But the caution is based on case reports and small studies, and the evidence is mixed as to whether statins truly create a mental fog.
In theory, excessive cholesterol lowering could impair brain cells’ membranes. On the other hand, statins can reduce the risk of stroke and improve blood flow to the brain, which could help prevent a form of dementia called vascular dementia.
The jury is still out on whether statins are the culprit here. And on another reassuring note, in the very few cases where people have reported memory issues, the problem has typically cleared up within a few days or weeks of stopping the medication.
4. Liver injury
Statins are thought to affect liver chemistry by changing lipid metabolism, and the Food and Drug Administration used to advise doctors to regularly monitor statin users’ liver enzymes. But recent research has shown that actual liver injury is rare, and now the standard of care is to measure liver enzymes before a patient starts a statin— and repeat the test only if there are symptoms of liver damage (such as jaundice, fatigue, and appetite loss).
Cataractsare a clouding of the eye’s lens, and animal research hints that statins can contribute to cataracts—possibly by hindering proper cell development within the lens, which needs a certain amount of cholesterol to remain transparent.
Results from human studies have been mixed, however. One study of more than 46,000 people found that statin users were 27 percent more likely than nonusers to have cataracts. But other studies have found no such link—and have even seen a lower risk among statin users. For now, any statin-cataract connection remains unclear.
6. Other questions
There is evidence, though nothing definitive, that statins can affect some other organs. One large study found that people on high-dose statins were more likely to suffer sudden kidney failure than people on low doses. However, that may be because less-healthy people tended to be on higher statin doses.
In other cases, there have been hints of benefits: Statin users have shown a lower risk of blood clots in the legs, and in one study, men with erectile dysfunction reported an improvement after starting a statin.
Now that statins have been so widely used, for so many years, researchers are learning more about the potential for unintended effects. In general, the heart benefits far outweigh any risks. But every patient should discuss his or her individual benefit-risk ratio with a doctor before starting on statin therapy. And if you notice new or unusual symptoms after you begin a statin, tell your doctor. A change in dose, a different statin, or another type of cholesterol drug may be in order.