How it works
What does amitriptyline do?
Amitriptyline is a tricyclic antidepressant.
Research suggests that depression is more likely to occur when the brain doesn’t have enough of the brain transmitters serotonin and noradrenaline.
Nerve endings in the brain release these chemicals to act on receptor targets. They are then taken back into the nerve endings in a recycle process.
Tricyclic antidepressants like amitriptyline block these transmitters being taken back up into the brain cells.
This means that more serotonin and noradrenaline are available to act on the receptor targets, which helps treat the symptoms.
How long does amitriptyline take to start working?
You should start to see some positive effects from amitriptyline after two weeks.
Your doctor is likely to increase your dose over the course of a month to find the right level for you.
If you do not feel much better after four weeks, you should go back to your doctor to review your treatment.
How long will I need to take amitriptyline?
You and your doctor should talk about how long you might need to take amitriptyline before you start your treatment.
Many people take amitriptyline for long periods.
If you take amitriptyline for low mood (depression) you will probably need to take it for at least a further six months after you feel well again, otherwise your symptoms are much more likely to come back.
If you have had more than one time when you felt depressed, you may take an antidepressant for up to two years, or even longer, to stop this happening again.
Your doctor needs to know if…
You need to talk to your doctor or pharmacist before starting treatment with amitriptyline if any of the following apply to you:
- you have any blood disorders (you may bruise easily, frequently suffer from infections or be anaemic)
- you have another mental health condition (e.g. schizophrenia or bipolar disorder)
- you have liver or heart disease
- you cannot urinate (go for a wee) easily
- you have an enlarged prostate gland
- you have an overactive thyroid gland and/or you are taking medicines to treat a thyroid disorder
- you have epilepsy
- you are being given electroconvulsive therapy (ECT)
- you have increased pressure in the eye (known as narrow-angle glaucoma)
- you are taking a monoamine oxidase inhibitor (MAOI), another type of antidepressant, or you have taken a MAOI within the previous 14 days for depression - MAOIs include moclobemide, isocarboxazid, phenelzine and tranylcypromine
- you have a problem with your blood called porphyria
You should only take amitriptyline as agreed with your doctor.
You will get the best from your medicine if you take it regularly, as prescribed.
Make sure that you know your dose. If it's not written on the label, check with your pharmacist or doctor.
You may have to take it more than once a day. Choose times that you can always remember. This could be mealtimes, or when you brush your teeth.
As amitriptyline can make you sleepy, it might be best to take it at nighttime, 30 minutes you go to bed.
If you are having problems because you must take it at school or work, or you are finding it hard to remember to take it more than once a day, talk to your doctor about your dosing schedule.
You can take it before or after food.
Swallow the tablets with a drink of water - if you chew them, they taste bitter.
What if I miss a dose?
If you forget to take a dose, then just take it as soon as possible.
If you forget to take it by your next dose, only take the next dose.
Do not take a double dose.
What will happen if I forget to take my amitriptyline?
If you forget to take your tablets for a few days, you may start getting withdrawal symptoms, including:
- flu-like symptoms (chills, muscle aches, sweating, headaches, feeling sick)
- strange dreams and disturbed sleep
- irritability and restlessness
You should talk to your doctor about these symptoms.
Stopping the use of amitriptyline
Stopping the medication causes the balance of chemicals in the brain to change.
Once you start taking amitriptyline, the brain adjusts to having new levels of serotonin and noradrenaline around.
If you stop taking the amitriptyline all at once, the balance starts to change again.
You could get some withdrawal symptoms from the change, including:
- feeling sick
- feeling weak and generally unwell
- feeling very happy or over-excited
- speech problems
If you want to stop taking amitriptyline, go to the doctor and they will help you to bring the dose down gradually. This will take a few weeks. You may still get some withdrawal effects, especially during the first two weeks as you reduce the dose. These effects will go away as you carry on reducing the dose. Talk to your doctor if they are uncomfortable and are affecting your life.
The information on this page was reviewed by the College of Mental Health Pharmacy in March 2020.