Simvastatin

Simvastatin is an HMG-CoA reductase inhibitor (statin) used for the management of hypercholesterolaemia and the prevention of cardiovascular disease. The landmark 4S and HPS trials established simvastatin as one of the first statins to demonstrate significant reductions in cardiovascular events and mortality. It is taken in the evening because cholesterol synthesis peaks at night, and simvastatin has a relatively short half-life.

How to Take Simvastatin

Take one tablet in the evening, with or without food. The evening dose is recommended because the body produces most of its cholesterol overnight, and simvastatin works best when taken at the time of peak cholesterol synthesis.

Avoid eating large amounts of grapefruit or drinking grapefruit juice while taking simvastatin, as it can significantly increase the level of the drug in your bloodstream and raise the risk of side effects. Take your tablet at roughly the same time each evening for consistency.

Start at 20 to 40 mg once daily in the evening. Maximum: 80 mg daily (restricted due to myopathy risk; new patients should not start on 80 mg).

Common Side Effects

Common side effects include:

• Headache
• Gastrointestinal discomfort (nausea, indigestion, or diarrhoea)
• Muscle pain or weakness (myalgia)
• Insomnia
• Skin rash

Muscle pain is the most important side effect to be aware of. While mild muscle aches are relatively common, a rare but serious condition called myopathy or rhabdomyolysis (breakdown of muscle tissue) can occur. Contact your doctor promptly if you develop unexplained, persistent muscle pain, tenderness, or weakness, particularly if combined with dark-coloured urine.

Report unexplained muscle pain. Many drug interactions via CYP3A4 (avoid with potent CYP3A4 inhibitors, large amounts of grapefruit juice). The 80 mg dose is restricted to patients already on it without muscle problems.

Contraindicated in active liver disease, pregnancy, breastfeeding, concurrent potent CYP3A4 inhibitors, and known hypersensitivity to simvastatin.