Desmopressin and oxybutynin in monosymptomatic nocturnal enuresis: a randomized, double-blind, placebo-controlled trial and an assessment of predictive factors.

OBJECTIVES

To assess the efficacy of desmopressin plus oxybutynin and compare two starting dosages of desmopressin (120 and 240 µg) in a randomized, double-blinded, placebo-controlled trial for children with monosymptomatic nocturnal enuresis (MNE) resistant to desmopressin. The predictive factors of children with MNE responsive to desmopressin and combination therapy were also evaluated.

PATIENTS AND METHODS

Our sample included 206 patients aged between 6 and 13 (mean age 10.6 ± 2.9 years), 117 males. All patients were required to have MNE. The patients were randomly divided into two groups: the first group was given oral melt 120 µg and the second group 240 µg, for 2 weeks. All patients who had experienced failure of treatment with sublingually administered desmopressin alone were given either desmopressin plus 5 mg oxybutynin or desmopressin plus placebo in a randomized, double-blinded trial for 4 weeks. As predictive factors, bladder volume and wall thickness index, nocturnal polyuria and voiding latency were considered.

RESULTS

There was no significant difference between the 120 µg and 240 µg patients in terms of response. The oxybutynin group showed a higher rate of full and partial responses (45% success) compared with the placebo group (17% success), P < 0.01. The responders to combined oxybutynin and desmopressin had significantly lower bladder volume and wall thickness index than the other patients.

CONCLUSIONS

Our findings highlight that anticholinergic agents may play an important role for a subset of children with enuresis who have a restricted bladder capacity and thickened bladder wall. Ultrasonography-measured bladder variables can provide useful predictive clues for MNE. Predictive factors can help to differentiate treatment subtypes and guide clinical management in primary nocturnal enuresis.