Overnight testing of renal concentrating capacity in children using desmopressin tablets: sensitivity, repeatability and non-inferiority versus intranasal spray.
OBJECTIVE
The purpose of this trial was to investigate whether a renal concentrating capacity test with desmopressin could be performed with oral tablets instead of the previously used nasal spray.


METHODS
A total of 154 children aged 3-18 years, who were candidates for a renal concentrating capacity test, were included in a randomized, double-dummy, crossover trial. The patients performed four tests: desmopressin tablets 0.6 mg (twice); desmopressin nasal spray 20 microg; and placebo.


RESULTS
A total of 118 patients qualified for the primary analysis. The mean osmolality was 978 mOsm/kg after nasal spray, 934 mOsm/kg after the tablet tests and 721 mOsm/kg after placebo. Desmopressin tablets were non-inferior to intranasal spray (lower 97.5% one-sided confidence limit= -67 mOsm/kg; non-inferiority limit= -69 mOsm/kg). The tablet test was reproducible and the within-patient SD between the two tablet tests was 111 mOsm/kg. Desmopressin tablets and spray produced a significantly higher urine osmolality compared to placebo (p<0.001). Eighteen patients reported a total of 25 adverse events, three of which occurred on placebo. Six events in four patients were judged as treatment-related, and all of these comprised either headache or abdominal pain. No serious adverse events were reported.


CONCLUSIONS
Desmopressin intranasal spray (20 microg) can be exchanged for desmopressin tablets (0.6 mg) in the assessment of renal concentrating capacity in children.
Asa Rembratt
Ferring Pharmaceutreals A/S, Copenhagen, Denmark.
Jens-Kristian Jensen
Kjell Tullus
Staffan Mårild
D050034:Antidiuretic Agents / Q000008:administration & dosage*; D002648:Child; D002675:Child, Preschool; D018592:Cross-Over Studies; D003894:Deamino Arginine Vasopressin / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D007671:Kidney Concentrating Ability / Q000187:drug effects* / Q000502:physiology; D007677:Kidney Function Tests / Q000379:methods*; D008297:Male; D009994:Osmolar Concentration; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013607:Tablets
D050034:Antidiuretic Agents; D013607:Tablets; D003894:Deamino Arginine Vasopressin