Bedwetting is a distressing and stressful condition for children and their families. Some children take longer than others to stop bedwetting. Up to 20% still wet at the age of five years, but by the age of 16 only 2% or less do so. Desmopressin is a drug which reduces bedwetting by reducing the amount of urine produced at night. It is taken before bedtime, and the children are also advised not to drink more than 240 ml (8 ounces) of fluid in the evening. However, it only works on the nights when it is used, so does not cure the problem in the long term.
When desmopressin is used, most of the children have fewer wet nights (one night less on average per week) and more become dry (19% compared with only 2% using dummy treatment in five trials involving 288 children). However, many children start wetting again when treatment stops. On the other hand, more children remain dry when alarm treatment is finished (54% after alarm compared with 35% after desmopressin in two trials involving 119 children). Adding desmopressin to alarm treatment did not result in better cure rates after the end of treatment (51% remained dry after combination treatment compared with 45% after alarm alone).
Those using desmopressin (or their parents) should be warned that over-drinking before bedtime should be avoided as this may lead to serious, but rare, adverse effects. Drugs called tricyclic antidepressants have a similar effect to desmopressin and are cheaper, but have more adverse effects. There are few adverse effects with alarms, other than short-term disruption for the family. In summary, alarms take longer to reduce bed-wetting, but their effect may persist longer than desmopressin.