Simvastatin

What is simvastatin?

Everyone has cholesterol and triglycerides in their blood. They are fatty substances needed by the body for many things. There are different types of cholesterol. Too much of the 'bad' cholesterol can block the blood vessels that supply your heart and brain with blood, and can cause heart attack, angina and stroke. The 'good' cholesterol helps to remove the bad cholesterol from the blood vessels.
Simvastatin is used to lower the level of cholesterol in your blood. 

Simvastatin is in a group of medicines called statins. Read more about statins – when are they used, their benefits and risks and other frequently asked questions about statins.

Dose

Simvastatin tablets are available in different strengths: 10 mg, 20 mg, 40 mg and 80 mg.

• The usual dose of simvastatin is 20 to 40 mg once a day.
• Always take your simvastatin exactly as your doctor has told you. The pharmacy label on your medicine will tell you how much simvastatin to take, how often to take it, and any special instructions.

How to take simvastatin

• Timing: Take simvastatin once a day. Simvastatin is best taken in the evening but its alright to take it anytime of the day that suits you, at around the same time each day. You can take simvastatin with or without food.
• Avoid large quantities of grapefruit. Having large quantities of grapefruit while taking simvastatin can increase your risk of side effects. But, eating one serving of marmalade, no more than half a grapefruit or drinking no more than a standard glass (250 mL) of grapefruit juice each day, should not be a problem if you are taking statins. It's best to allow 12 hours between having these foods and taking your simvastatin dose, so if you take your statin in the evening have your grapefruit in the morning. 
• Limit drinking large amounts of alcohol while you are taking simvastatin. Heavy drinking can increase your risk of side effects such as problems with your liver.
• Missed dose: If you forget your dose, take it as soon as you remember that day. But, if it is nearly time for your next dose, just take the next dose at the usual time. Do not take double the dose.
• Keep taking simvastatin regularly. To reduce your cholesterol effectively, you must keep taking simvastatin every day. Treatment with simvastatin is usually long term.

Precautions before starting simvastatin

• Do you have liver or kidney problems?
• Do you have problems with your thyroid?
• Do you have diabetes?
• Are your trying to get pregnant, think you might be pregnant, you're already pregnant, or you're breastfeeding?
• Do you drink large amounts of alcohol?
• Have you had, or do you have, a muscle disorder?

If any of these apply, it’s important that you tell your doctor or pharmacist before you start pravastatin. Sometimes a medicine isn’t suitable for a person with certain conditions, or it can only be used with extra care that your pharmacist will tell you about.

Precautions when taking simvastatin

• You may need to see your doctor regularly when you first start taking simvastatin to make sure the dose is right for you.
• To get the full benefit of a statin, it is important to keep a healthy diet and exercise often.

What are the side effects of simvastatin?

Like all medicines, simvastatin can cause side effects, although not everyone gets them. Often side effects improve as your body gets used to the new medicine.

Muscle pain or weakness

Some people will have muscle pain or weakness when taking statins. This is rarely serious and often goes away with time. If your pain comes on shortly after you start your statin, or gets worse, see your doctor. Your doctor will check an enzyme called creatine kinase to see if the aches and pains are possibly being caused or made worse by the statins. If so:

• a lower dose or a different statin may be prescribed, or
• you may choose to continue living with the aches because of the benefits of the statin, or
• you may discuss stopping taking your statin with your doctor.

Your doctor will also want to check for a rare but serious condition called rhabdomyolysis and will check any other medicines you are taking. Rhabdomyolysis can be caused by an interaction between statins and some other medicines including antibiotics.

Other side effects

Interactions

Simvastatin can interact with some medicines, including antibiotics, and herbal supplements, so check with your doctor or pharmacist before starting simvastatin or before starting any new medicines or supplements.

Learn more

Lipex; Simvastatin Mylan Medsafe Consumer Information Sheets
Simvastatin (Te Reo Māori) New Zealand Formulary Patient Information

References

1. Prescribing statins to reduce cardiovascular risk BPAC, 2017
2. Investigating myalgia in patients taking statins BPAC, 2014
3. Statins New Zealand Formulary
4. Simvastatin New Zealand Formulary

Useful resources for healthcare professionals

Simvastatin mylan Medsafe, NZ
Statin interactions – reports of serious myopathy Medsafe, NZ, 2011
Prescribing statins to reduce cardiovascular risk BPAC, NZ, 2017
Webinar – statins – who, when, where and why Goodfellow Unit, NZ, 2017