Simvastatin belongs to a group of medicines called statins.
Your doctor may prescribe simvastatin if you have a family history of heart disease, or a long-term health condition such as rheumatoid arthritis, or type 1 or type 2 diabetes.
The medicine is available on prescription as tablets. You can also buy a low-strength 10mg tablet from a pharmacy.
- Simvastatin seems to be a very safe medicine. It's unusual to have any side effects.
- Keep taking simvastatin even if you feel well, as you will still be getting the benefits. Most people with high cholesterol don't have any symptoms.
- Do not take simvastatin if you're pregnant, trying to get pregnant or breastfeeding.
- Do not drink grapefruit juice while you're taking simvastatin. It doesn't mix well with this medicine.
- Simvastatin is also called Zocor and Simvador.
Who can and can't take simvastatin
Simvastatin can be taken by adults and children over the age of 10 years.
Simvastatin isn't suitable for some people. Tell your doctor if you:
- have had an allergic reaction to simvastatin or any other medicines in the past
- have liver or kidney problems
- are trying to get pregnant, think you might be pregnant, you're already pregnant, or you're breastfeeding
- have severe lung disease
- regularly drink large amounts of alcohol
- have an underactive thyroid
- have, or have had, a muscle disorder (including fibromyalgia)
How and when to take it
Take simvastatin once a day in the evening. This is because your body makes most cholesterol at night.
Simvastatin doesn't upset the stomach, so you can take it with or without food.
How much will I take?
The usual dose for adults is between 10mg and 40mg once a day. People with very high cholesterol levels may be prescribed a higher dose of 80mg a day.
Your dose depends on the reason for taking it, your cholesterol levels, and what other medicines you're taking. Ask your doctor or pharmacist for advice if you're unsure how much to take. Don't reduce your dose without talking to your doctor first.
The usual starting dose in children is 10mg each evening. Your child's doctor might increase this after 4 weeks. The dose is based on your child's age, going up to a maximum of 40mg.
How to take it
Swallow simvastatin tablets whole with a glass of water.
There's some evidence simvastatin works better at lowering cholesterol if you take it in the evening rather than in the morning.
What if I forget to take it?
If you occasionally forget to take a dose, take your next dose the next day at the usual time. Never take 2 doses at the same time. Never take extra doses.
If you often forget doses, it may help to set an alarm to remind you. You could also ask your pharmacist for advice on other ways to help you remember to take your medicine.
What if I take too much?
Taking an extra dose of simvastatin by accident is unlikely to harm you.
Talk to your pharmacist or doctor if you're worried or if you take more than 1 extra dose.
Simvastatin seems to be a very safe medicine and it's unusual to have side effects. However, different statins can affect people in different ways.
Talk to your doctor or pharmacist if side effects bother you or don't go away. They may recommend taking a different statin.
One rare but serious side effect is unexplained muscle aches and pains. This is more likely if you're taking a higher dose of simvastatin - and it can happen a few weeks or months after you first start taking this medicine. Report any unexplained muscle pain, tenderness or weakness to a doctor straight away.
Another very rare side effect can be memory loss. This usually goes away when you stop taking the medicine.
Serious side effects
It happens rarely, but less than 1 in 1,000 people taking simvastatin may have a serious side effect.
Stop taking simvastatin and call a doctor if you get:
- muscle pain, tenderness, weakness or cramps - these can be signs of muscle breakdown and kidney damage
- yellow skin or the whites of your eyes turn yellow, or if you have pale poo and dark pee - this can be a sign of liver problems
- a skin rash with pink-red blotches, especially on the palms of the hands or soles of the feet
- severe stomach pain - this can be a sign of pancreas problems
- a cough, feeling short of breath, and weight loss - this can be a sign of lung disease
Serious allergic reaction
In rare cases, it's possible to have a serious allergic reaction (anaphylaxis) to simvastatin.
Call 999 or go to A&E if:
- you get a skin rash that may include itchy, red, swollen, blistered or peeling skin
- you're wheezing
- you get tightness in the chest or throat
- you have trouble breathing or talking
- your mouth, face, lips, tongue or throat start swelling
You could be having a serious allergic reaction and may need immediate treatment in hospital.
These are not all the side effects of simvastatin. For a full list see the leaflet inside your medicines packet.
You can report any suspected side effect to the UK safety scheme.
Pregnancy and breastfeeding
Simvastatin is not recommended in pregnancy and while breastfeeding.
Talk to your doctor if you're planning to become pregnant. It's best to stop taking simvastatin at least 3 months before you start trying for a baby.
If you become pregnant while taking simvastatin, stop taking the medicine and tell your doctor.
Simvastatin and breastfeeding
It's not known if simvastatin passes into breast milk, but it may cause problems for your baby. You may be able to stop taking simvastatin temporarily while you breastfeed.
Tell your doctor if you're:
- trying to get pregnant
Cautions with other medicines
Some medicines don't mix well with simvastatin, including:
- some antibiotics and antifungals
- some HIV medicines
- some hepatitis C medicines
- warfarin (stops blood clotting)
- ciclosporin (treats psoriasis and rheumatoid arthritis)
- danazol (treats endometriosis)
- nefazodone (treats depression)
- amiodarone (makes your heart stable)
- verapamil, diltiazem, amlodipine (for high blood pressure and heart problems)
If you're taking simvastatin and need to take one of these medicines, your doctor may:
- prescribe a lower dose of simvastatin
- prescribe a different statin medicine
- recommend that you temporarily stop taking your simvastatin
Mixing simvastatin with herbal remedies and supplements
St John's wort, a herbal medicine taken for depression, reduces the amount of simvastatin in your blood, so it doesn't work as well.
Talk to your doctor if you're thinking about starting St John's wort, as it will change how well simvastatin works.
Tell your doctor and pharmacist if you're taking any other medicines, including herbal remedies, vitamins or supplements.