Amitriptyline
A sedating tricyclic antidepressant used for depression and, at low doses, for nerve pain and to prevent migraine.
Drug card
- How it works
- Blocking norepinephrine and serotonin reuptake, plus several receptors
- Used for
- Depression
- Nerve pain (neuropathic pain)
- Migraine prevention
- Known for
- Drowsiness
- Dry mouth, blurred vision and constipation
- Its name
- -triptyline means a tricyclic antidepressant (amitriptyline type)
Study it as a flashcard, and it comes back before you forget it.
Mechanism of action
How does amitriptyline work?
Amitriptyline blocks norepinephrine and serotonin reuptake about equally, with strong anticholinergic and sedating effects. It also blocks sodium, potassium and NMDA channels, which may explain its pain relief, an effect separate from its antidepressant action. Its main active metabolite is nortriptyline.
Like other tricyclic antidepressants: Tricyclics block the norepinephrine (NET) and serotonin (SERT) transporters, so both transmitters build up in the synapse; how this relieves depression is not fully known. They also block muscarinic, H1-histamine and α1-adrenergic receptors, giving dry mouth, sedation and postural hypotension, and they block sodium channels, which widens the QRS complex and makes overdose dangerous to the heart.
Uses
What is amitriptyline used for?
- Depression
- Nerve pain (neuropathic pain)
- Migraine prevention
Side effects
Side effects of amitriptyline
- DrowsinessKnown for
- Dry mouth, blurred vision and constipationKnown for
- Difficulty passing urine
- Dizziness on standing
- Weight gain
- Fast heartbeat
- Heart block and arrhythmiasSerious
- Confusion and hallucinations, mainly in older people
- SeizuresSerious
- Suicidal thoughts in children and young adultsSerious
- Low sodium (SIADH)Serious
- Liver problems with jaundice, rarelySerious
Known for marks what an exam expects you to know it for.
Watch for
Cautions and what sets it apart
- Avoid in the recovery period after a heart attack, and do not combine with cisapride because of QT and arrhythmia risk.
- Never combine with an MAOI; leave at least 14 days after one is stopped.
- Toxic in overdose: supply small amounts to people at risk of suicide.
Good to know: Widely used at low doses for nerve pain and migraine prevention as well as for depression; it is usually taken in the evening because it causes sleepiness.
Remember it
A way to remember it
Three rings, three Cs: convulsions, coma and cardiotoxicity in overdose.
Tricyclics are named for their three-ring structure. In overdose they cause seizures, coma and dangerous heart rhythms with a widened QRS complex, so only small supplies are given to people at risk.
A mnemonic widely used in teaching
Its name
-triptyline means tricyclic antidepressant (amitriptyline type)
Amitriptyline and nortriptyline share it. Imipramine and clomipramine, also tricyclic antidepressants, end in -pramine, and -triptan (sumatriptan) marks migraine drugs.
- Every drug name stem
Its class
Tricyclic antidepressants
Other tricyclic antidepressants with a card:
Easily mixed up with serotonin-norepinephrine reuptake inhibitors and monoamine oxidase inhibitors.
Sources
Checked against
Written for biofideX in plain words, after checking these references:
- Amitriptyline hydrochloride tablets: label (DailyMed)
- Amitriptyline (NCI Thesaurus)
- Amitriptyline for pain and migraine (NHS)
- Amitriptyline 25 mg film-coated tablets: SmPC (emc)
For learning pharmacology, not for treatment decisions: no doses are given, and a prescriber, pharmacist or the product's own label is the word on any one patient. Spotted a mistake? Tell us and we'll correct it.
Depression, anxiety and sleep
Amitriptyline is one of 15 drugs practiced together here: their classes, how they work, what they treat and what they're known for.
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