Amitriptyline is a medicine used to treat pain.

It's especially good for nerve pain such as back pain and neuralgia.

It can also help prevent migraine attacks.

Amitriptyline is available on prescription. It comes as tablets and as a liquid.

Amitriptyline is also used to treat depression. Read about amitriptyline for depression.

• Amitriptyline is widely used to treat depression, but at lower doses it's also very good for treating pain.
• Amitriptyline can make you feel sleepy so it's best to take it in the evening or before you go to bed.
• You may notice a difference after a week or two but it can take 6 weeks for amitriptyline to work as a painkiller.
• Amitriptyline can cause extra side effects if you stop taking it suddenly. Talk to your doctor if you're thinking of stopping taking amitriptyline.

Amitriptyline can be taken by most adults. It can also be taken by children aged 2 to 17 years for some types of nerve pain.

Amitriptyline isn't suitable for some people. Check with your doctor before starting to take amitriptyline if you:

• have had an allergic reaction to amitriptyline or any other medicines in the past
• have a heart problem - amitriptyline can make some heart problems worse
• have a rare illness called porphyria
• have liver or kidney problems
• have epilepsy - amitriptyline can increase seizures
• have ever taken any medicines for depression - some rarely-used antidepressants can interfere with amitriptyline
• are trying to become pregnant, are already pregnant or you are breastfeeding - amitriptyline isn't always recommended in pregnancy or while breastfeeding
• have an eye problem called glaucoma - amitriptyline can increase the pressure in your eye
• have thoughts about harming yourself or ending your life

If you have diabetes, amitriptyline may change your blood sugar level. Check your blood sugar more often for the first few weeks of treatment with amitriptyline. Talk to your diabetes doctor if the reading goes too high or low.

It's usual to take amitriptyline once a day before bedtime because it can make you feel sleepy. If you find that you are still feeling drowsy in the morning you could try taking it earlier in the evening.

This medicine doesn't usually upset your tummy. You can take it with or without food.

Swallow the tablet with a drink of water - if you chew it, it tastes bitter.

How much will I take?

Amitriptyline tablets come in 3 different strengths - 10mg, 25mg or 50mg.

Liquid amitriptyline comes in 3 different strengths containing 10mg, 25mg or 50mg of amitriptyline in a 5ml spoonful.

The usual starting dose in adults and children aged 12 to 17 years is 10mg a day. This dose can be increased if you need better pain relief.

The starting dose for younger children depends on their weight and symptoms.

The maximum dose of amitriptyline for treating pain is 75mg a day. It can be higher if you're taking it to prevent migraine.

What if I forget to take it?

If you forget a dose, take it as soon as you remember, unless it's nearly time for your next dose. In this case, just leave out the missed dose and take your next dose as normal.

If amitriptyline makes you sleepy and you need to drive or use tools or machinery, leave out the missed dose and carry on with the next dose as normal.

Never take 2 doses at the same time. Never take an extra dose to make up for a forgotten one.

If you often forget doses, it may help to set an alarm to remind you. You could also ask your pharmacist for advice on other ways to help you remember to take your medicine.

What if I take too much?

Ask your doctor for advice straight away. An overdose can lead to potentially serious symptoms such as:

• vomiting
• shaking
• drowsiness
• change in your heartbeat
• seizures

Like all medicines, amitriptyline can cause side effects in some people, but many people have no side effects or only minor ones.

Some of the common side effects of amitriptyline gradually improve as your body gets used to it.

Common side effects

Because the dose of amitriptyline for pain is lower than the dose for depression the common side effects tend to be milder and go away within a few days.

Keep taking the medicine but talk to your doctor or pharmacist if these side effects bother you or don't go away:

• constipation
• dizziness
• dry mouth
• feeling sleepy
• difficulty peeing
• headache

Serious side effects

It happens rarely, but some people have a serious side effect after taking amitriptyline.

Call a doctor straight away if you get:

• a fast or irregular heartbeat
• yellow skin, or the whites of your eyes go yellow - these can be signs of a liver problem
• a headache, feel confused or weak, get muscle cramps or a seizure - these can be signs of a low sodium level in your blood
• thoughts about harming yourself or ending your life
• eye pain, a change in your eyesight, swelling or redness in or around the eye
• severe constipation or you're unable to pee and it's causing severe tummy pain
• weakness on one side of your body, trouble speaking or thinking, loss of balance or blurred eyesight - these can be signs of a stroke

If you suspect that you or someone else is having a stroke, phone 999 immediately and ask for an ambulance.

Serious allergic reaction

In rare cases, it's possible to have a serious allergic reaction to amitriptyline.

These are not all the side effects of amitriptyline. For a full list see the leaflet inside your medicines packet.

What to do about:

• constipation - eat more high-fibre foods such as fresh fruit and vegetables and cereals. Try to drink several glasses of water or another non-alcoholic liquid every day. If you can, it may also help to do some exercise. Watch a short video on how to treat constipation.

• dizziness - this is probably due to low blood pressure. Drink plenty of water or a non-alcoholic drink. Do not stand up too quickly after sitting or lying down.

• dry mouth - chew sugar-free gum or sugar-free sweets.

• feeling sleepy or tired - take amitriptyline in the evening and cut down the amount of alcohol you drink. Don't drive or use tools or machinery if you're feeling this way.

• difficulty peeing - relax when you try to pee. Don't try to force the flow of urine. If it doesn't happen, try again later. Talk to your doctor urgently if you can't pee at all.

• headaches - make sure you rest and drink plenty of fluids. Don't drink too much alcohol. Talk to your doctor if the headaches last longer than a week or are severe.

Amitriptyline is generally not recommended in pregnancy or while breastfeeding. Your doctor will only prescribe amitriptyline for your pain while you're pregnant or breastfeeding if the benefits of taking the medicine outweigh the risks.

Amitriptyline has been linked with a small risk of problems for the unborn baby if you take it in early or late pregnancy.

Talk to your doctor as there may be other painkillers you can take instead of amitriptyline.

Paracetamol is usually the first choice of painkiller if you're pregnant or breastfeeding. Read more about paracetamol in pregnancy.

For more information about how amitriptyline can affect you and your baby during pregnancy, read this leaflet on the Best Use of Medicines in Pregnancy (BUMPS) website.

Amitriptyline and breastfeeding

Amitriptyline is not usually recommended if you're breastfeeding.

Amitriptyline gets into breast milk. It's been linked with side effects like sleepiness in breast fed infants. Talk to your doctor if you want to breastfeed. There may be other medicines that you can take instead of amitriptyline.

Many medicines and amitriptyline can interfere with each other and increase the chances of side effects.

Tell your doctor if you have ever taken any medicines for depression. Some rarely-used antidepressants can interfere with amitriptyline to cause very high blood pressure even after you have stopped taking them.

Make sure that your doctor and pharmacist know you're taking amitriptyline before starting or stopping any other medicine.

Mixing amitriptyline with herbal remedies and supplements

Do not take St John's wort, the herbal remedy for depression, while you are being treated with amitriptyline. It will increase your risk of side effects.