Simvastatin: uses, side effects and grapefruit warning

Simvastatin is used to treat high cholesterol and to prevent heart attacks and strokes, according to the NHS. It is also prescribed for people with diabetes, kidney disease or familial hypercholesterolaemia.

It has been in use for a long time and is available as a generic. The brand the NHS names is Zocor. You may find it supplied as tablets or, for people who struggle with tablets, as a liquid suspension.

The NHS advice is to take simvastatin at the same time each day, usually in the evening. It can be taken with or without food, and tablets should be swallowed whole with a drink of water.

Your prescriber may begin with a low dose and raise it after four weeks if needed. The page does not set out fixed doses, so follow the figure on your prescription label.

Missed a dose? Skip it and carry on at the usual time; the NHS is firm that you should not take two to catch up.

Simvastatin is not suitable for everyone. Check with a prescriber or pharmacist if you have had an allergic reaction to a statin, have liver or kidney problems, an underactive thyroid, a muscle disorder, or if you drink heavily. These are the same groups the NHS flags for the statin class generally.

It is a medicine to keep taking unless a doctor says otherwise. The NHS warns that when people stop, cholesterol levels can climb back up.

Simvastatin has an unusually long list of named clashes. The NHS lists antifungals such as itraconazole and ketoconazole, antibiotics including fusidic acid, erythromycin and clarithromycin, certain antivirals, the immune drug ciclosporin, the antidepressant nefazodone, danazol and other cholesterol medicines. It also names the heart and blood pressure drugs amlodipine, diltiazem and verapamil.

Grapefruit juice sits in the same category: the NHS says to avoid drinking it because it can stop the medicine working properly. If a short course of antibiotic or antifungal is prescribed, make sure whoever prescribes it knows you take simvastatin.

The NHS lists headache, dizziness, nausea, constipation, diarrhoea, indigestion, wind, muscle aches and sleep problems as the commoner effects. Mention anything that bothers you or persists to a pharmacist or doctor.

Rare but serious effects include inflammation of the liver, inflammation of the pancreas, damage to muscle and serious allergic reaction. Severe muscle pain or weakness, yellowing of the skin or eyes, or severe tummy pain warrant urgent advice from NHS 111; swelling of the throat or breathing difficulty needs 999.

The NHS says simvastatin is not recommended in pregnancy because it can affect how a baby develops, and that it should be stopped three months before trying to conceive. For breastfeeding, the NHS notes it is not usually used because it is not known whether the medicine passes into breast milk; a different statin may be discussed.

Alcohol can increase the risk of side effects, so avoid heavy drinking. Simvastatin does not usually affect driving, but wait until any dizziness has gone before getting behind the wheel.

If simvastatin does not suit you or interacts with something you need, other statins such as atorvastatin, rosuvastatin and pravastatin are options for a prescriber to consider, as is ezetimibe. You can report a suspected side effect yourself through the MHRA Yellow Card scheme.