Muscle weakness is a well known side effect of statin use. This symptom is very commonly ignored both by the patients and the doctors. Recent studies suggest that the higher potency statins i.e the ones causing a bigger drop in cholesterol/mg of active product are also the ones more likely to cause muscle weakness as a side effect. In order of potency the statins are as followed : 1) Rosuvastatin 2) Atorvastatin 3) Simvastatin 4) Pravastatin 5) Lovastatin So, it is always better not just to look at the altered hepatic functions during follow up visits. Do ask about the adverse side effects also and use a less potent statin if required.