Examples

Tricyclic antidepressants (TCAs) come in tablet form and are usually taken in the evening. But they may be taken midafternoon and at bedtime, which can help prevent accidental wetting that occurs early in the night.

How It Works

The exact way that TCAs help reduce bed-wetting is not known. They may affect the muscles of the bladder, or they may have some effect on the hormone that causes the kidneys to release urine (antidiuretic hormone). They may work by causing the child to sleep more lightly.

Why It Is Used

TCAs may help decrease bed-wetting for short periods of time for children 6 years and older. These medicines most often are used with another form of treatment such as praise and encouragement (motivational therapy).

• TCAs are most helpful for children who have normal-sized bladders. They also work well for children who had periods of bladder control before starting treatment.
• TCAs work best for older children and children who do not have frequent daytime accidental wetting.

How Well It Works

Both imipramine and desipramine have been shown to reduce the number of wet nights and help children have 14 dry nights in a row. ¹

About half of the children who take imipramine for bed-wetting are able to control bed-wetting, at least for a short time. After they stop taking the medicine, about 30 out of 100 of those children will wet the bed again. ²

Side Effects

Side effects that may occur with TCAs include:

• Constipation.
• Dry mouth.
• Nervousness.
• Anxiety.
• Difficulty sleeping (insomnia).
• Mood or personality changes.

Other side effects that are less common include:

• Headaches.
• Abdominal pain.
• Decreased appetite.
• Blurred vision.
• Uncontrollable crying.

If a child takes a larger dose (accidental overdose), death could occur. A child who has taken an overdose of a TCA may have:

• A very fast heartbeat.
• Seizures.
• Coma (cannot be awakened).
• Low blood pressure (hypotension).

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)

What To Think About

Imipramine is being used less often because other medicines have been more effective and have fewer risks. Because there have been rare reports of deaths associated with imipramine use, the benefits of using it need to outweigh the risks.

TCAs usually are given for 3 to 4 months and then tapered off over 3 to 4 weeks until they are stopped altogether. They also may be used for shorter lengths of time such as for camps, overnight outings, or vacation. Ask the doctor if your child should try the medicine for 6 weeks before the outing. Then you can tell if it will work when your child needs it to.

TCAs should not be used to treat children younger than 6 years of age.

TCAs have not been shown to be helpful in stopping bed-wetting in older teens or children who have small bladders.

TCAs are not recommended for long-term treatment of accidental wetting. Some children actually get worse the longer they take TCAs. The reason for this is not known.

If TCAs are stopped suddenly, without tapering off the dosage, accidental wetting usually starts again.

The U.S. Food and Drug Administration (FDA) has issued an advisory on this kind of medicine and the risk of suicide. The FDA does not recommend that people stop using these medicines, but to watch for warning signs of suicide in those using them. This is especially important at the beginning of treatment or when doses are changed.

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Citations

1. Kiddoo D (2007). Nocturnal enuresis, search date March 2007. Online version of BMJ Clinical Evidence. Also available online: http://www.clinicalevidence.com.

2. Boris NW, Dalton R (2007). Enuresis (bed-wetting) section of Vegetative disorders. In RM Kliegman et al., eds., Nelson Textbook of Pediatrics, 18th ed., pp. 113–115. Philadelphia: Saunders Elsevier.