Imipramine has been used to treat bedwetting since the 1960s. It predates bedwetting alarms, desmopressin, and most of the interventions now recommended in clinical guidelines — yet it has never fully disappeared from practice. If your child’s GP or paediatrician has mentioned it, or if you’ve come across it in your own research, here is a straightforward account of what it does, how well it works, and what the safety considerations actually mean.
What Is Imipramine?
Imipramine is a tricyclic antidepressant. It was originally developed to treat depression in adults and is still used for that purpose. Its effect on bedwetting was noticed incidentally and has been used off-label for nocturnal enuresis for decades. It is not a first-line treatment in current UK guidelines, but it remains a licensed option and is listed in the British National Formulary (BNF) for children aged seven and over.
It is available in tablet form and is usually taken once daily, shortly before bedtime.
How Does Imipramine Work for Bedwetting?
The honest answer is that the mechanism is not fully understood, even now. Several theories have been proposed:
- Anticholinergic effect: Imipramine relaxes the bladder muscle, reducing urgency and increasing functional bladder capacity.
- Antidiuretic effect: It may increase ADH (antidiuretic hormone) secretion, reducing overnight urine production — similar in effect to desmopressin, though less predictably.
- Sleep architecture changes: Some researchers have suggested it alters sleep depth, making children more arousable. This theory has largely fallen out of favour but hasn’t been disproved entirely.
- Central nervous system effects: As a tricyclic, imipramine acts on multiple receptor systems simultaneously, which may contribute to its effect through pathways not yet clearly mapped.
In practice, it is likely that the bladder and antidiuretic effects together account for most of the clinical benefit.
How Effective Is It?
Imipramine produces a meaningful response in around 40–50% of children — typically defined as a significant reduction in wet nights rather than complete dryness. Full dryness while on the medication occurs in roughly 20–30% of cases, depending on the study and the dose used.
The more significant issue is relapse. When imipramine is stopped, a high proportion of children — some estimates suggest over 50% — return to their previous wetting pattern. This makes it less useful as a long-term solution and more relevant as a short-term management tool, for example ahead of a school trip, holiday, or other specific period.
By comparison, the bedwetting alarm achieves full dryness in approximately 60–70% of users with a much lower relapse rate, and desmopressin offers reliable short-term suppression with a well-established safety profile. Both are recommended ahead of imipramine in NICE guidance (CG111). Imipramine tends to be considered when those approaches have failed or are not suitable.
Who Might Be Offered Imipramine?
Imipramine is more likely to be considered in the following circumstances:
- First-line treatments (alarm, desmopressin) have been tried without adequate response
- Desmopressin is contraindicated or poorly tolerated
- There is a specific short-term need — such as a trip — and the alarm is not practical
- A specialist has reviewed the case and considers it appropriate alongside other management
It is not typically prescribed by GPs without specialist input, given the cardiac safety considerations. If you have reached this point in your child’s care, you are probably working with a paediatrician or continence clinic. If you feel your concerns are not being addressed, see our guide on what to do when a GP isn’t listening.
Safety and Side Effects: What the Concerns Actually Are
This is the section that matters most, and it deserves directness.
Cardiac Risk
Imipramine affects cardiac conduction — specifically the QT interval. In overdose, this effect can cause serious, potentially fatal arrhythmias. This is not a theoretical concern: there are documented cases of accidental poisoning in children who accessed medication intended for an older family member, and in children whose dose was excessive relative to body weight.
At therapeutic doses prescribed for an individual child, the cardiac risk is considered low. But the safety margin between therapeutic and toxic doses is narrower than with desmopressin, which is why imipramine requires more careful management:
- Baseline ECG before starting, and sometimes during treatment
- Weight-adjusted dosing, reviewed regularly
- Strict storage: medication must be kept completely out of reach and inaccessible to the child and any siblings
- Clear guidance on what to do if a dose is missed or accidentally doubled
If a prescriber offers imipramine without discussing storage safety and cardiac monitoring, ask specifically about both.
Other Side Effects
Common side effects at bedwetting doses are generally mild and often transient:
- Dry mouth
- Constipation (worth noting if constipation is already a contributing factor in your child’s bedwetting)
- Mild sedation the following morning
- Mood changes — irritability or low mood in some children, though this is more commonly reported at higher antidepressant doses
- Reduced appetite
Constipation is worth flagging specifically because it is both a side effect of imipramine and an independent cause of bedwetting. If your child already has constipation, it is worth discussing this with the prescriber before starting.
Interactions
Imipramine interacts with several medications. If your child takes anything regularly — including ADHD medication, antihistamines, or epilepsy treatment — the prescriber should review interactions before starting. Do not assume this has been checked; confirm it explicitly.
Practical Points If Imipramine Is Prescribed
- Start low, go slow. Dosing typically starts at 25mg for children aged 7–11 and may be increased if there is a partial response. The prescriber should set a clear review point.
- Allow at least two weeks. Response is not always immediate. A trial period of four weeks is common before assessing effect.
- Do not stop abruptly without guidance. Although imipramine is not habit-forming in the same way as some medications, abrupt discontinuation can cause discontinuation symptoms including nausea and sleep disturbance.
- Keep a record. Track wet and dry nights during the trial. This makes the review appointment more useful and helps the prescriber assess response accurately.
- Storage is non-negotiable. Lockable medicine storage is a reasonable precaution. If other children are in the household, this is not optional.
Imipramine Alongside Other Management
Medication alone rarely resolves bedwetting without attention to the wider picture. While imipramine is being used, it is still worth considering fluid management, toileting routines, and bedding protection. If you are currently managing frequent wet nights and haven’t found a product that reliably contains overnight wetting, the articles on why overnight pull-ups leak and how to stop leg leaks are worth reading alongside any medical treatment.
There is also the emotional dimension — particularly for older children who have been through multiple treatment attempts. For families at that stage, this guide on next steps when nothing has worked sets out the options more broadly.
What the Guidelines Say
NICE guideline CG111 (Nocturnal enuresis: the management of bedwetting in children and young people) places imipramine third in line — after the alarm and desmopressin. It notes that imipramine should only be prescribed by, or under the supervision of, a paediatrician or specialist, and that treatment should not exceed three months without review.
The guideline also makes the important point that bedwetting has a high rate of spontaneous resolution and that all treatment decisions should weigh benefit against risk, particularly in younger children. For children under seven, imipramine is not recommended.
A Realistic Summary
Imipramine for bedwetting is a legitimate, evidence-based option with a long track record — but it comes with a narrower safety margin than the alternatives. It is most useful when first-line treatments have not worked and there is a clear short-term goal, or when a specialist has a specific reason to prefer it. The cardiac safety considerations are real and should be managed, not minimised.
If your child has been offered imipramine, the right response is to understand the monitoring requirements clearly, ensure secure storage, and track the response systematically. If you are still deciding whether to pursue specialist input, this guide on when to see a doctor can help you assess where you are in the process.
