Statins are cholesterol-lowering medicines. They may be used to treat:

• primary hypercholesterolaemia, a high level of cholesterol in the blood due to lifestyle factors such as a high-fat diet or not doing enough exercise
• familial hypercholesterolaemia, a high level of cholesterol in the blood due to inheriting a gene that causes your liver to make lots of cholesterol

Statins may also be used to reduce your risk of having a heart attack or stroke if you have:

• angina (chest pain) or have previously had a heart attack
• transient ischaemic attacks ('mini strokes') or have previously had a stroke
• peripheral vascular disease (narrowing of blood vessels, usually in the legs)
• diabetes and are over 40
• diabetes and are under 40 but have other risk factors for heart disease, such as poor blood sugar control, high blood pressure or a family history of heart disease in a relative younger than 40

How statins work

Statins reduce the production of cholesterol by the liver.

In particular, they reduce the production of 'bad' cholesterol called low density lipoprotein (LDL).

If you have a high amount of LDL cholesterol in your blood, it can form fatty deposits in the lining of your arteries (blood vessels). This causes furring and narrowing of the arteries, known as atherosclerosis, which in turn restricts the blood flow and can increase your risk of having heart disease or a stroke.

The liver makes most of your body's cholesterol at night. For this reason, it is recommended that many statins (fluvastatin, pravastatin, simvastatin and simvastatin with ezetimibe) are taken in the evening so the amount of statin in your body will be highest when the liver is producing the most cholesterol.

Names

There are several different statins. Names include:

• atorvastatin (brand name Lipitor)
• fluvastatin (brand name Lescol)
• pravastatin (brand name Lipostat)
• rosuvastatin (brand name Crestor)
• simvastatin (brand name Zocor)
• simvastatin combined with ezetimibe (brand name Inegy)

When to avoid statins

Statins should not be taken if you have:

• liver disease
• persistently abnormal liver function blood tests

Before you start taking a statin, your doctor should ensure your liver function is normal. This involves carrying out a blood test to check for the liver enzyme (substance in the blood) serum transaminase.

This should be repeated one to three months after you start taking the statin and at six-month to one-year intervals while you are taking it. If the amount of serum transaminase in your blood rises to and stays at three times the upper limit of normal, your doctor will advise you to stop taking the statin.

Simvastatin

The statin called simvastatin should not be taken if you are taking medicines that slow down its breakdown by the liver. These include:

• some antibiotics (medicines for infection), including erythromycin, clarithromycin, itraconazole and ketoconazole
• some medicines for HIV (human immunodeficiency virus) infection, including indinavir, lopinavir, ritonavir and saquinavir

If you take these medicines and also need treatment for high cholesterol, you may take one of the other statins.

Pregnancy and breastfeeding

Statins should not be taken by women who are pregnant or breastfeeding.

Using statins with caution

Statins should be taken with caution if you have risk factors for developing the rare side effects of myopathy and rhabdomyolysis (types of muscle disorder that cause muscle pain and breakdown of muscle tissue). These risk factors include:

• being over 70 years old
• having a history of liver disease
• drinking large quantities of alcohol
• having a history of muscle side effects when taking a statin or fibrate (another type of medicine for high cholesterol)
• having a family history of myopathy (muscle damage) or rhabdomyolysis (kidney damage caused by a substance called myoglobin that is released into the blood when your muscles are inflamed or damaged)

If you have an underactive thyroid, only take a statin if your thyroid problem is being treated and is under control.

Statins are generally very well tolerated and most people will not experience any side effects. For more specific information on side effects for a particular statin, see Medicines information.

Muscle effects

Statins can occasionally cause inflammation (swelling) and damage to your muscles. Speak to your doctor if you experience muscle pain, tenderness or weakness that cannot be explained (for example, not due to physical work).

Your doctor will carry out a blood test to measure a substance in your blood called creatinine kinase (CK), which is released into the blood when your muscles are inflamed or damaged. If the level of CK in your blood is more than five times the normal level, your doctor will advise you to stop taking the statin. Once your CK level has returned to normal, your doctor may suggest you start taking the statin again, but at a lower dose.

Common side effects

Up to 1 in 10 people may experience the following:

• gastrointestinal disorders, such as constipation, diarrhoea, dyspepsia (acid in the stomach) and flatulence (passing wind)
• headache
• insomnia (difficulty sleeping)
• myalgia (pain in the muscles) and arthralgia (pain in the joints)
• nausea (feeling sick)

Less common side effects

Up to 1 in 100 people may experience the following:

• loss of appetite
• myopathy (muscle damage)
• peripheral neuropathy (loss of sensation or pain in the nerve endings of the hands and feet)
• skin rash
• vomiting (being sick)

Rare and very rare side effects

Between 1 in 1,000 and 1 in 10,000 people may experience the following:

• dizziness
• hepatitis (inflammation of the liver)
• rhabdomyolysis, kidney damage caused by a substance caused myoglobin, which is released into the blood when a muscle is severely inflamed and damaged

Statins can interact with other medicines. Some of the more common interactions are listed below. However, this is not a complete list.

If you want to check that your medicines are safe to take with statins, ask your doctor or pharmacist, or read the patient information leaflet that comes with your medicine.

Amiodarone

Amiodarone can increase your risk of myopathy (muscle damage) if taken with atorvastatin or simvastatin. It is not known to interact with the other statins.

Ciclosporin

Ciclosporin can increase your risk of myopathy (muscle damage) from statins. If you are taking ciclosporin along with atorvastatin, the dose of atorvastatin should not be more than 10mg a day.

Daptomycin

You have an increased risk of myopathy (muscle damage) when daptomycin and statins are taken together.

Diltiazem

Diltiazem can increase your risk of myopathy (muscle damage) if taken with atorvastatin or simvastatin.

Ezetimibe

You have an increased risk of myopathy (muscle damage) when ezetimibe and statins are taken together.

Fibrates

Fibrates (such as bezafibrate, ciprofibrate, fenofibrate or gemfibrozil) can increase your risk of myopathy (muscle damage) if taken with statins. The risk is greatest with gemfibrozil, which should not be taken with statins.

Nicotinic acid

Nicotinic acid can increase your risk of myopathy (muscle damage) from statins.

Medicines to treat HIV

Some medicines used to treat HIV, including amprenavir, atazanavir, indinavir, lopinavir, nelfinavir, ritonavir and saquinavir, can increase your risk of myopathy (muscle damage) if taken with atorvastatin or simvastatin. Your risk is greatest with simvastatin, which should not be taken with any of the above medicines for HIV.

Antibiotics

Some antibiotics, including erythromycin, clarithromycin, itraconazole, ketoconazole and miconazole, can increase your risk of myopathy (muscle damage) if taken with atorvastatin or simvastatin.

Speak to your doctor if you are taking atorvastatin or simvastatin and need to take one of these antibiotics. Your doctor may advise you to stop taking atorvastatin or simvastatin or take a lower dose of the statin while you are on the course of antibiotics.

Verapamil

Verapamil can increase your risk of myopathy (muscle damage) if taken with atorvastatin or simvastatin. The other statins do not interact with verapamil.

Warfarin

Statins can enhance the effect of warfarin, which may increase your risk of bleeding.

You should have regular blood tests to monitor the effect of your statin on the warfarin, especially when starting or stopping a statin or when changing the dose of statin.

Take statins as directed on the packet or patient information leaflet, or as directed by your GP or pharmacist.

Missed dose

If you forget to take your dose of statin, take that dose as soon as you remember and then continue to take your course of statins as normal.

If you have to take two doses closer together than normal, there is an increased risk of side effects.

The patient information leaflet that comes with your medicine should give you advice on what to do. If you are still concerned, speak to your GP or pharmacist, or call NHS Direct on 0845 46 47.

Accidentally taking one extra dose

Accidentally taking one extra dose of statins is unlikely to cause you harm. If you are concerned, speak to your GP or pharmacist, or call NHS Direct on 0845 46 47.

Accidentally taking more than one extra dose

If you accidentally take more than one extra dose of your statins, contact your GP or call NHS Direct on 0845 46 47 as soon as possible.