Get emergency medical help if you have any of these signs of an allergic reaction to simvastatin: hives; difficult breathing; swelling of your face, lips, tongue, or throat.
In rare cases, simvastatin can cause a condition that results in the breakdown of skeletal muscle tissue, leading to kidney failure. Call your doctor right away if you have unexplained muscle pain, tenderness, or weakness especially if you also have fever, unusual tiredness, and dark colored urine.
Also call your doctor at once if you have:
signs of a kidney problem - little or no urinating; painful or difficult urination; swelling in your feet or ankles; feeling tired or short of breath; or
muscle weakness in your hips, shoulders, neck, and back;
trouble lifting your arms, trouble climbing or standing; or
liver problems - nausea, upper stomach pain, itching, tired feeling, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes).
Common simvastatin side effects may include:
headache;
constipation, nausea, stomach pain; or
cold symptoms such as stuffy nose, sneezing, sore throat.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
 Simvastatin side effects (more detail)
