Side effects from statins can include constipation, diarrhea, gas, headaches, and joint pain. But a more potentially serious side effect is muscle pain and weakness—mild to severe cases occur in about 5 to 10 percent of all people who take a statin, although a recent survey found that the figure could be as high as 32 percent. And, higher doses have also been linked to an increased risk of a life-threatening form of muscle breakdown called rhabdomyolysis, which can lead to permanent kidney damage, coma, and even death. About one in 10,000 or fewer might develop that problem.
Other recent research utilizing the Centers for Disease Control and Prevention's National Health and Nutrition Examination Survey (NHANES) found that adults who took statins were 50 to 60 percent more likely to have pain in their lower back and lower extremities than adults who didn't use them.
Another concern is a slightly increased risk of diabetes. A recent large analysis of 13 statin studies published in the medical journal Lancet found that the drugs were associated with an increased risk of developing diabetes by 9 percent. (Diabetes increases your chances of having a heart attack, stroke, and other health problems.) In a group of men and women taking statins over four years, one additional person in 255 would develop diabetes. (But more research is needed to understand the specific cause.)
Other side effects and adverse events have been associated with statin use. A 2010 study that included a large-scale analysis of more than 225,000 patient records of men and women in the U.K. taking a statin found an increased risk of liver problems—especially during the first year of use—particularly true at higher doses for women. An estimated one in 100 people who take statins might develop abnormal liver-function tests—a sign of liver injury.
Increases in the risk of cataracts and acute kidney failure have also been associated with statins. Over the course of five years, in women with a medium risk of heart disease, an additional one in 40 treated with statins developed cataracts, one in 154 developed moderate or serious liver dysfunction, and one in 313 developed moderate or serious muscle weakness. One additional woman in 593 developed acute kidney failure.
Cognitive problems have also been associated with some statins. Other reported associations have included depression, severe irritability, and even cancer. All of these should be studied further. Women who are (or might become) pregnant should not take statins at all since there is proof that they can cause birth defects.