Using desmopressin acetate (DDAVP) to cure bedwetting in children doesn't hold water.
Researchers examining 18 randomized controlled trials of a total of 581 children receiving DDAVP found no real benefit.
Although all studies but one showed a significant instant reduction in bedwetting, two weeks later, only a quarter of the children became dry.
Among the 28 children followed long term, only a fifth remained dry for 12 weeks after stopping the drug.
Another study comparing the drugs with conditioning alarms found the alarms to be more effective.
In reporting these results, Journal Watch (published by The New England Journal of Medicine) commented: "Because conditioning alarms are about 70 per cent effective and DDAVP costs about $120 (£80) per month, DDAVP should not be a first line treatment for noctural enuresis."