What is amitriptyline and how is it used?
Amitriptyline is a type of drug called a tricyclic antidepressant. Although these are used for anxiety and depression, lower doses are also widely used to block the long-term (chronic) pain of some rheumatic conditions. Some other antidepressants can also be used for chronic pain.
Chemical changes in the spinal cord and brain (central nervous system) can affect pain regulation and lead to increased pain and distress. Amitriptyline rebalances the chemicals in the central nervous system, which can relieve pain, relax the muscles and improve sleep. It can also help with any anxiety and depression resulting from the pain, though low doses are not enough on their own to treat severe depression.
Amitriptyline can be prescribed by a consultant rheumatologist for chronic pain caused by:
- spinal problems
- chronic (tension) headaches
- damage to nerve endings in limbs (peripheral neuropathy).
Amitriptyline won’t be prescribed if:
- you’re recovering from a recent heart attack (myocardial infarction)
- you have a condition called heart block
- you have extreme mood swings (uncontrolled bipolar disorder)
- you have acute porphyria
- you have certain forms of glaucoma.
If you respond well to amitriptyline, the effect on sleep is usually immediate, and your pain and mood will improve within two to six weeks. Because it can sometimes take a while to find the right dose, it’s often helpful to keep taking amitriptyline:
- even if it doesn’t seem to be having much effect at first
- even if you’re having some side effects – as these usually become less troublesome as your body becomes more tolerant of the drug.
When and how do I take amitriptyline?
Amitriptyline is taken in tablet or syrup form every day. It has a sedative effect and may make you drowsy, so you should take it an hour or two before bed, but no later than 8pm.
Your doctor will advise you about the correct dose. Usually you will start on 5–10 mg and gradually increase it to 20 mg daily. However, higher doses (e.g. 50 mg, 75 mg) may be used if your pain is very severe and disturbing your sleep.
If you wish to stop taking amitriptyline you will probably be advised to reduce the dose gradually to avoid sleep disturbance.
Possible risks and side-effects
The most common side-effect is a dry mouth, but you may also feel drowsy or spaced out in the morning or during the day, especially if you take the amitriptyline too late at night. Take care when driving or operating machinery.
Less common side-effects are:
- difficulty passing urine, especiallyin men with prostate problems
- dizziness due to a fall in blood pressure, especially in older people
- blurred vision
- weight gain or loss.
If you do have side-effects it’s often worth continuing the treatment as they usually lessen with time. But if you have any unusual side-effects or symptoms that concern you, see your doctor immediately.
Take extra care if:
- you’re being treated for epilepsy – amitriptyline may cause more frequent seizures
- you have heart problems – see your doctor if you experience an irregular heartbeat while on amitriptyline
- you have glaucoma – make sure you have regular eye tests with an optician.
There is no evidence that amitriptyline is addictive or causes dependency, especially at low doses.
If you find amitriptyline isn’t right for you, then speak to your doctor who may suggest other treatments, for example:
- imipramine (another tricyclic antidepressant)
- SNRIs (serotonin-noradrenaline reuptake inhibitors)
- SSRIs (selective serotonin reuptake inhibitors).
These are less sedative than amitriptyline, so may be helpful if drowsiness is a problem for you.
Taking other medicines
Amitriptyline may be prescribed along with other drugs to treat your condition. However, some drugs may interact with it, so check with your doctor before starting any new medications, and remember to mention you’re on amitriptyline if you’re treated by anyone other than your usual doctor.
- You may be prescribed painkillers (such as codeine or tramadol) alongside amitriptyline. This could make you drowsier.
- Occasionally, an SNRI or SSRI antidepressant may be prescribed in combination with amitriptyline. In this case more careful monitoring may be needed, especially if you’re also having treatment for blood pressure or heart problems.
- Don’t take over-the-counter or herbal remedies without discussing this first with your healthcare team.
You should avoid alcohol as amitriptyline increases its effects and may make you more drowsy. This is especially important when driving or using machinery.
You can have vaccinations while on amitriptyline.
Fertility, pregnancy and breastfeeding
Amitriptyline has no effect on fertility for men or women. Studies of this drug used at higher doses to treat depression haven’t shown any particular problems in relation to pregnancy, so its use at low dose during pregnancy is unlikely to be a problem.
Speak to your doctor if you become pregnant, or want to try for a baby, while on amitriptyline. Don’t stop taking amitriptyline suddenly or without speaking to your doctor first.
Very little of the drug has been found in the breast milk of mothers taking high doses of amitriptyline, so breastfeeding while you’re on amitriptyline is unlikely to be harmful. Discuss this with your doctor if you do wish to breastfeed.