BackgroundAlthough the evidence-based treatment for nocturnal enuresis is established, nearly one-third of patients are still enuretic with desmopressin, anti-cholinergic treatment and alarm. The fourth option, imipramine, is limited because of the risk of cardiotoxicity on overdose. Clonidine, an (2)-adrenoceptor agonist that also has noradrenergic effects like imipramine, is a new option for refractory enuresis. MethodsA total of 148 patients (6-14 years of age; mean, 9.1 years) with refractory enuresis under desmopressin, anti-cholinergic treatment and alarm were enrolled. The patients consisted of 100 boys and 48 girls, of whom 23 had monosymptomatic nocturnal enuresis and 125 had non-monosymptomatic nocturnal enuresis. Clonidine 4 g/kg/day (maximum, 75 g/day) orally 30 min before bedtime was added and its effects were evaluated after 4 weeks of treatment. ResultsA total of 83 patients (56.1%) achieved partial or complete response with the additional clonidine. No significant adverse reactions were noted. ConclusionsClonidine could be an aid for refractory enuresis, although further randomized controlled trials are needed.