A sedating tricyclic antidepressant
Trimipramine
A sedating tricyclic antidepressant used for depression, particularly where sleep is disturbed, but dangerous in overdose.
What is Trimipramine?
Trimipramine is a tricyclic antidepressant (TCA) used to treat depression, especially when sleep problems and anxiety are prominent, because it is one of the more sedating members of its group. It usually takes a few weeks to work, can cause anticholinergic effects such as dry mouth and constipation, and is dangerous in overdose — so it is used carefully and not stopped suddenly.
Education and reference only. This is a plain-language guide to Trimipramine — it deliberately contains no doses. Doses depend on the person, the brand and the reason for treatment, and belong with your prescriber. Always check the BNF, the product labelling (SmPC) and follow medical advice.
What it is
Trimipramine is a tricyclic antidepressant (TCA), one of the older classes of antidepressant. It is used to treat depression, and because it is markedly sedating it is often chosen when low mood comes with disturbed sleep or anxiety, frequently taken in the evening. While effective, TCAs have more side effects than newer antidepressants and are dangerous if too much is taken, so they are prescribed with care.
How it works
Trimipramine increases the activity of the brain chemicals (neurotransmitters) noradrenaline and serotonin by reducing their reuptake, which is thought to help lift mood over several weeks. It also blocks other receptors — histamine, acetylcholine and others — which produces its strong sedating effect and its anticholinergic side effects such as dry mouth, blurred vision and constipation. Its effects on the heart's electrical system are also why it is dangerous in overdose.
Company & origin
Originated / developed by: Rhône-Poulenc (now Sanofi).
Trimipramine is a tricyclic antidepressant (TCA) introduced in the 1960s. It is one of the more sedating members of the group, so it has often been chosen for depression where poor sleep and anxiety are prominent.
What it treats
Conditions Trimipramine is used for
Practical use
How to take Trimipramine
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- Take it regularly as prescribed, usually in the evening because it is sedating — it can take a few weeks to lift your mood, so keep going even if you feel no change at first.
- Do not stop it suddenly; it is reduced gradually under your prescriber's guidance to avoid withdrawal effects.
- Take care with driving and operating machinery, especially at first, and be aware you may feel drowsy the next morning.
- Avoid or strictly limit alcohol, as it adds to drowsiness.
- Keep it well out of reach of children and only keep the amount you need at home, because it is dangerous in overdose.
- Tell your prescriber if you have a fast or irregular heartbeat, fainting, or thoughts of harming yourself, especially in the early weeks.
Weighing it up
Advantages & disadvantages of Trimipramine
Advantages
- Effective for depression, with long clinical experience behind it.
- Its sedating effect can be helpful when low mood comes with poor sleep and anxiety.
- Taken once a day in the evening, fitting a simple routine.
Disadvantages
- Dangerous in overdose because it can disturb the heart's rhythm — a serious safety concern, so only limited amounts are kept at home.
- Causes anticholinergic effects (dry mouth, constipation, blurred vision, urinary difficulty) and can cause next-day drowsiness.
- Must not be stopped suddenly, and takes weeks to show its full effect.
- More side effects than newer antidepressants, so it is often not the first choice.
Practical use
Good to know
Trimipramine usually takes a few weeks to lift mood, so it is important to keep taking it and not give up early; sleep and appetite often improve before mood does. It is markedly sedating and is often taken in the evening to help with sleep, but it can cause a 'hungover' drowsiness the next morning. It must not be stopped suddenly, as this can cause withdrawal effects; it is reduced gradually with the prescriber. Importantly, tricyclic antidepressants are dangerous in overdose because they affect the heart, so only the amount needed is kept at home. Alcohol should be avoided or limited, as it adds to drowsiness.
Who should not take it / use with caution
- People who have recently had a heart attack, or who have certain heart-rhythm or conduction problems.
- People taking a monoamine oxidase inhibitor (MAOI) antidepressant, or within a short period of stopping one.
- Used cautiously in older people, in those prone to urinary retention or with glaucoma, epilepsy, severe liver disease, or a history of mania.
Monitoring
- Mood, response to treatment and any thoughts of self-harm, especially in the early weeks
- Heart rate and rhythm where relevant, and blood pressure on standing
- Side effects such as drowsiness, dry mouth and constipation, with review of the amount kept at home
Side effects
- Drowsiness (sometimes lingering into the morning), dizziness on standing, and weight gain.
- Anticholinergic effects: dry mouth, blurred vision, constipation and difficulty passing urine.
- Effects on heart rhythm, especially in overdose where they can be life-threatening; rarely, a possible increase in suicidal thoughts early in treatment, particularly in younger adults.
Key interactions
- Monoamine oxidase inhibitors (MAOIs) must not be combined — a dangerous reaction can occur.
- Other sedating medicines and alcohol add to drowsiness; other medicines that affect heart rhythm increase the risk of rhythm problems.
- Other anticholinergic medicines worsen dry mouth, constipation and confusion; care is also needed with some other antidepressants that raise serotonin.
Available as: Tablets and capsules taken by mouth.
Answers
Trimipramine: frequently asked questions
How long does trimipramine take to work?
Sleep and anxiety often improve within days because it is sedating, but the lift in mood usually takes a few weeks to build. It is important to keep taking it as prescribed and not give up early. Speak to your prescriber if you notice no improvement after several weeks.
Why is trimipramine dangerous in overdose?
Tricyclic antidepressants like trimipramine can disturb the heart's electrical rhythm, which can be life-threatening if too much is taken. For this reason only the amount needed is usually kept at home, and it is kept well away from children. If an overdose is suspected, seek emergency help immediately.
Can I stop trimipramine once I feel better?
Do not stop it suddenly, as this can cause withdrawal effects such as flu-like feelings, sleep disturbance and low mood. Treatment is usually continued for a period after you feel well to prevent relapse, then reduced gradually under your prescriber's guidance.
Why does it make me so drowsy?
Trimipramine is one of the more sedating tricyclic antidepressants, which is partly why it is chosen when sleep is poor. Taking it in the evening uses this to help sleep, but it can cause drowsiness the next morning. Take care with driving and machinery, and avoid or limit alcohol.
Can I drink alcohol while taking it?
It is best to avoid or strictly limit alcohol. Trimipramine is sedating, and alcohol adds to this, increasing drowsiness, dizziness and the risk of accidents. Take particular care with driving and operating machinery, especially when you first start the medicine.
The wider class
About Tricyclic antidepressants
Trimipramine belongs to the tricyclic antidepressants class. For how the class as a whole works, its shared safety principles and monitoring, see the full guide.
Browse by body system
Authoritative sources
- BNF: Trimipramine.
- NICE CKS: Tricyclic antidepressants.
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