Tricyclic antidepressants
Imipramine
One of the original tricyclic antidepressants, used for depression and also for night-time bed-wetting in children, effective but with notable side effects and danger in overdose.
What is Imipramine?
Imipramine is a tricyclic antidepressant, one of the first of its kind, used mainly for depression and also for night-time bed-wetting in children. It takes some weeks to work and commonly causes anticholinergic effects such as dry mouth, constipation and blurred vision. It is dangerous in overdose because of its effects on the heart, and should not be stopped suddenly.
Education and reference only. This is a plain-language guide to Imipramine — 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
Imipramine is a tricyclic antidepressant (TCA) and was the first of its class. In the UK it is used for depression and also has a role in treating night-time bed-wetting (nocturnal enuresis) in children when other measures have not worked. Newer antidepressants such as SSRIs are usually tried first for depression because they are better tolerated and far safer in overdose, but imipramine is still used in selected situations.
How it works
Imipramine raises the levels of the brain chemicals serotonin and noradrenaline by stopping them being reabsorbed into nerve cells, which gradually lifts mood over several weeks. It also blocks other receptors, which causes its anticholinergic side effects such as dry mouth and constipation and its effects on the heart that make it dangerous in overdose. In bed-wetting, its effect on the bladder and on sleep is thought to help.
Company & origin
Originated / developed by: Geigy (now part of Novartis).
Imipramine was developed by the Swiss company Geigy (later part of Novartis) in the 1950s and was the first tricyclic antidepressant, marking a milestone in the treatment of depression.
What it treats
Conditions Imipramine is used for
Practical use
How to take Imipramine
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- Take it regularly as prescribed, even before you feel a benefit.
- For depression it can take a few weeks to work, so do not stop early.
- It can be sedating, so it is sometimes taken in the evening; follow your prescriber's advice.
- Do not stop suddenly; coming off it should be done gradually with your prescriber.
- Keep it well out of reach of children, as it is dangerous in overdose.
- Tell your prescriber about any heart problems before starting.
Weighing it up
Advantages & disadvantages of Imipramine
Advantages
- Effective, well-established treatment for depression.
- Has a recognised role in night-time bed-wetting in children.
- A useful option when newer antidepressants have not helped.
Disadvantages
- Commonly causes anticholinergic effects (dry mouth, constipation, blurred vision).
- Dangerous in overdose because of effects on the heart.
- Takes some weeks to work for depression.
- Should not be stopped suddenly, as this can cause withdrawal effects.
- Needs caution in people with heart disease.
Practical use
Good to know
Imipramine takes time to work for depression, usually a few weeks, so it is important to keep taking it and not stop early. It commonly causes anticholinergic side effects such as dry mouth, constipation and blurred vision. It is dangerous in overdose because of its effects on heart rhythm, so it is prescribed and stored with care, which is especially important when it is used for children. It should not be stopped suddenly, and it is used with caution in people with heart disease.
Who should not take it / use with caution
- People who have recently had a heart attack or have certain heart rhythm problems.
- People with a known allergy to imipramine.
- People taking, or who have recently taken, an MAOI antidepressant.
- Use with caution in people with heart disease, epilepsy, glaucoma, urinary problems or an enlarged prostate, and in older people.
Monitoring
- Mood, and any thoughts of self-harm, especially early in treatment.
- Heart health, particularly where there is existing heart disease.
- Side effects such as constipation, urinary problems and drowsiness.
Side effects
- Dry mouth, constipation and blurred vision.
- Drowsiness and dizziness.
- Weight changes and sweating.
- Difficulty passing urine.
- Effects on heart rhythm, which is why it is dangerous in overdose.
Key interactions
- MAOI antidepressants, which must not be combined with it.
- Other medicines that affect heart rhythm.
- Other sedating medicines and alcohol, which increase drowsiness.
- Tell your prescriber and pharmacist about all your medicines.
Available as: Tablets, and a liquid (oral solution) used in some situations.
Answers
Imipramine: frequently asked questions
Why is imipramine used for bed-wetting in children?
Imipramine can help reduce night-time bed-wetting, thought to be through its effect on the bladder and on sleep. It is usually considered when other measures, such as an alarm, have not worked, and it must be stored very safely because it is dangerous in overdose.
How long does imipramine take to work for depression?
It usually takes a few weeks before the benefit builds. It is important to keep taking it and attend follow-up, even if you do not feel better straight away.
Is imipramine dangerous in overdose?
Yes. Like other tricyclic antidepressants, imipramine can be dangerous in overdose because of its effects on heart rhythm. Keep it safely away from children and seek urgent help if too much is taken.
Why does imipramine cause a dry mouth and constipation?
These are common anticholinergic side effects of tricyclic antidepressants. Sips of water and a high-fibre diet can help; tell your prescriber if they are troublesome.
Can I stop imipramine suddenly?
No. Stopping suddenly can cause withdrawal effects such as nausea, restlessness and trouble sleeping. It should be reduced gradually under your prescriber's guidance.
The wider class
About Tricyclic antidepressants
Imipramine belongs to the tricyclic antidepressants class. For how the class as a whole works, its shared safety principles and monitoring, see the full guide.
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Authoritative sources
- BNF: Imipramine.
- NICE CKS: Imipramine.
- electronic Medicines Compendium (SmPC): Imipramine.
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