What is amitriptyline?
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.
If amitriptyline works for you the effect on sleep is usually immediate, and your pain and mood are likely to improve within two to six weeks.
Amitriptyline can be prescribed by a consultant rheumatologist for chronic pain caused by:
- back pain and neck pain
- chronic (tension) headaches
- damage to nerve endings in the limbs (peripheral neuropathy).
Are there any reasons I won't be prescribed amitriptyline?
Amitriptyline won't be prescribed if you're recovering from a recent heart attack (myocardial infarction) or if you have:
- a condition called heart block
- uncontrolled bipolar disorder (extreme mood swings)
- acute porphyria (an enzyme disorder causing severe nerve or skin symptoms)
- certain forms of glaucoma (increased pressure within the eyeball).
How is it taken?
Amitriptyline is taken as tablets or syrup every day. It has a sedative effect and may make you drowsy, so you should take it an hour or two before bedtime (but no later than 8 pm).
Your doctor will advise you about the correct dose. Usually you'll start on 5–10 mg a day, and gradually increase it to 20 mg a day. However, your doctor may increase your dose to 50 mg or 75 mg if your pain is very severe and disturbing your sleep.
If you wish to stop taking amitriptyline you'll probably be advised to reduce the dose gradually over a few weeks to avoid sleep disturbance.
How long does it take to work?
If amitriptyline works for you, the effect on sleep is usually immediate, and your pain and mood are likely to improve over 2–6 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.
Side-effects and risks
The most common side-effect is a dry mouth. 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.
Make sure you take the dose no later than 8 pm or try starting with a very low dose and building up gradually over a few weeks, which may reduce side-effects.
Take care when driving or operating machinery.
Less common side-effects include:
- difficulty passing urine – especially in men with prostate problems
- dizziness – due to a fall in blood pressure, especially in older people
- blurred vision
weight gain or weight loss.
There's no evidence that amitriptyline is addictive or causes dependency, especially at low doses.
What should I do if I experience side-effects?
If you do have side-effects, it's often worth continuing the treatment as they'll 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.
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.
Effects on other treatments
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 (for example, codeine or tramadol) alongside amitriptyline – this could make you more drowsy.
- If you're prescribed a combination of an SNRI or SSRI antidepressant and amitriptyline, you may need more careful monitoring, especially if you're also on treatment for blood pressure or heart problems.
- Don't take over-the-counter preparations or herbal remedies without discussing this first with your healthcare team.
You can have vaccinations while on amitriptyline.
It's recommended you should avoid alcohol while you're on amitriptyline because it increases the effects of alcohol and may make you more drowsy. This is especially important if you're driving or using machinery.
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 it 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.