Desmopressin Acetate (DDAVP)
DDAVP is a drug to treat children with bed-wetting. Although DDAVP does not cure the condition, it does help treat the symptoms while the child is on the drug. Numerous studies report reduction in the number of wet nights.
DDAVP is a man-made copy of a normal body chemical that controls urine production. The therapeutic benefit of DDAVP might be due to a reduction in the overnight production of urine or possibly to an effect on arousal.
Many studies have attempted to identify those childrens most likely to respond to DDAVP. Older children are more responsive. Children with a normal bladder capacity are more likely to respond than those with a small bladder size.
The drug can be taken as a nasal spray or tablet. However, the tablet has several advantages. If your child has no problems swallowing pills, the tablet is more discreet for sleepovers and other special occasions. Additionally, the tablet has reported a better response rate. The nasal spray can be affected by a stuffy nose from colds or allergy. DDAVP should be given at bedtime. Because it works right away, it does not need to be given everyday to be effective.
DDAVP has few side effects. The most common side effects with the nasal spray are nasal discomfort, nosebleeds, tummy pain, and headache. The only serious side effect noted in children treated with DDAVP is seizure due to water intoxication. This serious problem is preventable with care not to overdo fluids on any evening that DDAVP is taken. Children should take only one eight once cup of fluid at supper, no more than 8 ounces between supper and bedtime, and nothing to drink in the two hours before bedtime. Early symptoms of water intoxication include headache, nausea, and vomiting. If these symptoms occur, the medication should be stopped and the child should be seen by a doctor immediately. Caution should be used in children with attention deficit hyperactivity disorder since they are often impulsive. These children might require especially close monitoring of their fluid intake.
Imipramine has been used successfully for many years to treat children with bed-wetting. Complete dryness has been reported in 10-50% of patients. Some children who are not completely dry show significant improvement.
How this drug works is not well understood. Even though imipramine is a type of antidepressant, there is nor reason to suggest that depression plays a role in the cause of bed-wetting.
This type of drug is thought to work one of several ways:
- by changing the child's sleep and wakening pattern
- by affecting the time a child can hold urine in the bladder or
- by reducing the amount of urine produced.
Imipramine generally is not used to treat bed-wetting in children younger than 6 to 7 years of age. Success rates have been found to be higher in older children. As with all drugs used to treat bed-wetting if the drug is stopped, bed-wetting is likely to reoccur.
The usual dose of imipramine is taken 1 to 2 hours before bedtime for children 6 to 8 years old. A higher dose is needed for older children and adolescents. A child should be seen by a doctor after three to six months on the drug. If the child starts wetting again, then a repeat course of treatment may be restarted.
It is very important to take the drug in the amount prescribed by your doctor. Minor side effects of imipramine include irritability, insomnia, drowsiness, reduced appetite, and rarely, unpleasant personality changes. However, most children who take imipramine for bed-wetting do not experience these side effects. If they do occur, the side effects can be easily reversed by reducing or stopping the medication. Of more serious concern, imipramine can lead to death if an overdose is taken, therefore, it must be kept out of the reach of all children and sealed with a child proof cap. Accidental overdoses have been reported in children.
Anticholinergic drugs, such as oxybutynin (Ditropan) or hyosyamine (Levsinex), reduce or stop bladder contractions and increase bladder capacity. Anticholinergics may be helpful for children who have daytime wetting due to bladder contractions and/or small bladder capacity. A useful formula for estimating normal bladder volume in children is: age in years + 2 = ounces.
Anticholinergics alone are usually not helpful fo rchildren with isolated bed-wetting without any daytime voiding problems. However, some children with bedwetting who fail to respond to DDAVP alone will respond to a combination of DDAVP and an anticholinergic. This is often true for a child who has reduced functional bladder capacity. The reason behind this approach is that the DDAVP reduces night time urine output while the anticholinergic increases nighttime bladder colume. Together, these drugs may prevent bed-wetting by keeping the bladder from becoming full during the night.
For children older than 6 years, the dose of oxybutynin (Ditropan XL) is given once a day to children with daytime wetting symptoms. Another anticholinergic, hyoscamine, is also available in a long acting time capsule. The usual dosage is one hyosyamine twice daily. For children with isolated bed-wetting, only the bedtime dose of oxybutynin or hyosyamine is required. Common side effects are dry mouth and facial flushing. Occasionally, flushing may occur when the child is exposed to hot weather. An overdoes may result in blurring of vision and hallucinations. Fewer side effects have been reported with a newer anticholinergic, tolterodine (Detrol), which is more specific for its action on the bladder. However, this drug is not yet approved for use in children under twelve years.
Drug therapy of bedwetting is best thought of as a treatment, not a cure. Therefore, most children require long-term treatment to prevent a return of bed-wetting.
Reported response rates are similar for DDAVP and imipramine. DDAVP is more costly than imipramine, but it has fewer side effects and is less toxic. DDAVP plus an anticholinergic may be helpful in some children who have small bladder capacity. Anticholinergics may also help children who have small bladder capacity and daytime frequency, urgency and/or wetting. However, anticholinergics alone have not proved helpful for children with only night time wetting.