Hi, Crestor contains rosuvastatin that belongs to the group of medications known as statins or also known as cholesterol lowering medications is used to reduce the level of bad cholesterol named LDL in the blood, raise the level of good cholesterol named HDL, decrease the level of fat called triglycerides in the blood, slow the deposition of fat in the arterial wall and thus prevent the patients from future heart attacks or strokes. Side effects of Crestor are muscle pain, weakness or tenderness, joint pain, leg pain, shoulder pain, feeling of sensation of tingling, burning or numbness in the hands or feet, headache, sweating, depression, nausea, abdominal pain, insomnia, nightmares, constipation, weakness in the hips, shoulders, neck or back, allergic reactions etc. Though having side effects, you should not stop taking this medication without consulting your doctor first. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Zubayer Alam, General And Family Physician