Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.
A very small number of people taking simvastatin may have mild memory problems or confusion. If these rare effects occur, talk to your doctor.
This drug may infrequently cause muscle problems (which can rarely lead to very serious conditions called rhabdomyolysis and autoimmune myopathy). Tell your doctor right away if you develop any of these symptoms during treatment and if these symptoms persist after your doctor stops this drug: muscle pain/tenderness/weakness (especially with fever or unusual tiredness), change in the amount of urine.
This medication may rarely cause liver problems. If you notice any of the following rare but serious side effects, tell your doctor immediately: yellowing eyes/skin, dark urine, severe stomach/abdominal pain, persistent nausea/vomiting.
A very serious allergic reaction to this drug is rare. However, seek immediate medical attention if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.
This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.
In the US -
Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.