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.
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 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)
- 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:
- 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
Ability to drive
Statins are unlikely to affect your ability to drive. However, they may occasionally cause dizziness. If this affects you, do not drive.
Interactions with other Medicines
Interactions with food and Grapefruit Juice
- Avoid drinking grapefruit juice if you are taking simvastatin. Grapefruit juice reduces the breakdown by the liver of simvastatin, which raises the level of simvastatin in the blood and makes you more likely to get side effects.
- Atorvastatin interacts with grapefruit juice if you drink large quantities, but an occasional glass is thought to be safe. It is safe to drink grapefruit juice if you are taking any of the other statins.