Desmopressin Melt Therapy in Patients With Nocturnal Polyuria: a Pharmacokinetic/Dynamic Study

The objective of this study is to find out what the pharmacokinetic/dynamic (PK/PD) characteristics of desmopressin melt are in nocturia patients (compared to healthy volunteers and children). The main questions the investigators want to answer are:

* Are differences related to the pathophysiological factors involved in nocturia?
* Are there age/gender/size differences?
* Can the investigators identify patients who are likely to develop hyponatraemia?
* Can the investigators individualize treatment and reduce risk for hyponatraemia?

Day 1:

* Patient is being hospitalized in the morning
* General anamnesis and clinical examination
* Uroflow and residue measurements (3x)
* Sober blood sample, to determine plasma concentrations of Na+, Cl-, osmolality and creatinin

Day 1-2:

- In the evening at 20h:

* start (with empty bladder!) 24h miction-incontinence-residue registration: urine collections every 3 hours (every portion of urine within a period of 3 hours must be collected in the same collection device), with: registration of volumes and measurement urinary concentrations of Na+, Cl-, osmolality and creatinin
* Measurement of blood pressure during 24h

Day 2-3:

* In the evening at 19h (day 2): drink 15mL/kg water
* At 20h: take desmopressin melt 120µg + start:

  * 24h miction-incontinence-residue registration: registration of volumes and measurement urinary concentrations of Na+, Cl-, osmolality and creatinin (U1-U7)
  * Measurement of blood pressure during 24h
  * Collection of urine:U1 at 19h, U2 at 20h, together with intake of first desmopressin melt, U3 at 21h = 1h after desmopressin melt intake, U4 at 22h = 2 after desmopressin melt intake,U5 at 23h = 3h after desmopressin melt intake, U6 at 2h (day 3) = 6h after desmopressin melt intake, U7 at 8h = 12h after desmopressin melt intake
  * Blood samples for blood levels of desmopressin: 1h, 2h, 3h, 6h after desmopressin melt intake, 12h after desmopressin melt intake + plasma concentrations of Na+, Cl-, osmolality and creatinin (safety profile)
  * At 8h in the morning (day 3): drink 15mL/kg water + collection of urine per hour during 3h with measurement of urinary concentrations of Na+, Cl-, osmolality and creatinin: U8 at 9h, U9 at 10h, U10 at 11h
* Patient can go home on day 3, unless he is at high risk for side effects, high-risk patients are hospitalized for 7 days


Eligibility Criteria:
Inclusion Criteria:

* written informed consent prior to the performance of any study-related activity
* patients, men and woman, 18 years and older, with nocturnal polyuria, resulting in nocturia (2 voids or more at night) and/or nocturnal incontinence.

Exclusion Criteria:

* hypersensitivity/anaphylactic reaction on desmopressin or one of the other substances
* pregnancy
* genitourinary tract pathology (infection, tumor,...)
* urolithiasis
* suspicion or evidence of cardiac failure
* moderate to severe renal insufficiency (creatinin clearance \< 50 ml/min)
* psychogenic or habitual polydipsia
* hyponatraemia or predisposition for hyponatraemia
* diabetes insipidus
* syndrome of inadequate ADH production