In clinical trials 5 to 10% of subjects demonstrate intolerability, but some suspect the actual degree of intolerance among people who use the drugs in real life can be as high as 20%. (Clinical trial participants are selected for criteria which may inadvertently lower their risk for intolerance.) This does not mean the patients should necessarily quit taking statins. Raise the issue with your doctor.
Doctors distinguish between tolerability and safety.
Safety refers to whether the drug produces a measurable negative health effect that makes it untenable to continue treatment. The most common safety issue with statins is myopathy, which affects only about 1 in 10,000 people, and which a blood test for liver enzymes is performed in the weeks after initiation of treatment.
Intolerability is a looser and more lifestyle-related concept. A drug may be intolerable if it is bothersome or has side effects that have little medical significance but which make the patient want to quit treatment. For statins, intolerability may manifest as aches and pains in skeletal muscles, memory problems, back pain, and fatigue. When a medication is found to be unsafe for a patient the medication can unequivocally be stopped. (If enough patients are harmed, the drug can be pulled from the market.) When a medication is intolerable, often the best course is for the patient to buck up and continue with the discomfort. (Patients have to work this out with their doctors, of course.) More on this: http://informahealthcare.com/doi/full/10.1586/17512433.2014.857601
Tolerability problems are often what makes people quit their statin regimens. An intermittent dosing schedule may be a work-around for these patients.
Researchers at the Cleveland Clinic found that patients who had been found unable to tolerate statins were in most cases able to tolerate them when the regimen was restarted. Over 70% of previously intolerant people were able to handle a daily or weekly regimen when supervised by doctors at the clinic. This suggests if people can “push through” their initial bouts with intolerance, they will be able to enjoy the real benefits of statins.
The the American College of Cardiology recently released an application for mobile phones to help doctors manage statin intolerance in their patients.