A drug called desmopressin can help children have fewer wet nights. It works in a similar way to a natural hormone in your child's body. It makes their urine more concentrated, so they don't make as much of it.
Desmopressin comes as tablets and as a pill that dissolves under your child's tongue. It works quickly, but your child will probably start wetting the bed again once they stop taking it. It may be useful for sleepovers or holidays, but bedwetting alarms may work better in the long run.  
Desmopressin isn't used for children under 5 years.  And it's not usually recommended for children under 7 years.
Some brand names for desmopressin are:
Your doctor will prescribe desmopressin for your child to take at bedtime for up to three months. If a lower dose doesn't work, your child's doctor may suggest trying a higher dose.  
One summary of the research (called a systematic review) found that children who take desmopressin at bedtime wet the bed less at night and are more likely to become dry.  But four small studies showed that some children start wetting the bed again when they stop taking the medicine.
It's not clear how which works better, desmopressin or a bedwetting alarm. One summary of the research said desmopressin works faster, but children are more likely to stay dry for several months if they use a bedwetting alarm.  Another study said there wasn't much difference between the success rates of the two treatments. 
Your child may take desmopressin and use a bedwetting alarm at the same time. But studies have found that using the two treatments together works no better than using an alarm on its own. And children taking desmopressin are more likely to start wetting the bed again when treatment stops.   
Because desmopressin makes your child's urine more concentrated, it can affect the balance of water and salt in their body.  So, only give your child a drink when they're thirsty. If your child is going to do a lot of exercise, or if the weather is hot and likely to make them thirsty, they shouldn't take desmopressin.  And if your child is going swimming, they need to be careful not to swallow too much water.
You shouldn't give your child desmopressin if they are vomiting or they have diarrhoea. 
Desmopressin is less likely to cause side effects than other medicines used to treat bedwetting. However, about 1 in 20 children who take desmopressin get side effects. These include:  
A sore throat
Very rarely, taking desmopressin can lead to a seizure or a coma, caused by too much fluid in the body. 
Desmopressin is also available as a nasal spray. But you shouldn't use the nasal spray for your child if they are bedwetting. This is because seizures are more likely when using the nasal spray than with taking desmopressin tablets.