While Simvastatin belongs to the same group of medications as Atorvastatin, and both treat high levels of cholesterol and triglycerides in the blood effectively, they are in fact not the same treatment.
Clinical studies reveal that atorvastatin is slightly more effective in reducing low-density lipoprotein cholesterol (LDL-C) than simvastatin. After taking medicines for 8 weeks, LDL-C levels for patients taking atorvastatin reduced by 42.5% while for those receiving simvastatin it was 34.8%.[popover id=ref4]
Both atorvastatin or simvastatin have good safety profiles[popover id=ref4] (simvastatin is slightly safer and more tolerable than other statins[popover id=ref5]), so are usually well tolerated by patients. Some side effects may occur which go away once your body adjusts to the medicine. Frequency of some side effects may differ for both. Simvastatin is a newer class especially prescribed for patients who have side effects to statins.
Atorvastatin and simvastatin are to be taken at different times of the day. Simvastatin, a short acting enzyme, should be taken at night, when it is most effective. Atorvastatin is commonly prescribed to be taken at night as it is a long acting medication.
Whether Atorvastatin or Simvastatin is best for you will depend on a number of factors that will need to be discussed with your doctor.