• Change from baseline in mean number of nocturnal voids [ Time Frame: week 4 ] [ Designated as safety issue: No ]
• Proportion of subjects with greater than 33 percent reduction from baseline in mean number of nocturnal voids [ Time Frame: Week 4 ] [ Designated as safety issue: No ]
• Durability of effect in mean number of nocturnal voids [ Time Frame: months 1-6 ] [ Designated as safety issue: No ]

• Change from baseline in total sleep time [ Time Frame: months 1-6 ] [ Designated as safety issue: No ]
• Change from baseline in initial period of undisturbed sleep [ Time Frame: months 1-6 ] [ Designated as safety issue: No ]
• Change from baseline in Quality of Life [ Time Frame: months 1-6 ] [ Designated as safety issue: No ]
• Change from baseline in quality of sleep [ Time Frame: months 1-6 ] [ Designated as safety issue: No ]
• Treatment safety [ Time Frame: months 1-6 ] [ Designated as safety issue: No ]

The purpose of this study is to investigate the efficacy and safety of several doses of the melt formulation of desmopressin in a broad population of adult patients with nocturia.

• Drug: desmopressin acetate
• Drug: Placebo

• Placebo Comparator: Participants will take a placebo 'melt' for 28 days to complete part 1 of the study. In part 2, placebo patients will be randomized to one of the other four treatment arms to receive active desmopressin melt for between 1-6 months (until the database for part 1 is locked and treatment is unblinded).
• Experimental: Participants will take desmopressin melt 10 μg for 28 days to complete part 1 of the study. Participants will continue on this dose in study part 2 for between 1-6 months (until the database for part 1 is locked and treatment is unblinded).
• Experimental: Participants will take desmopressin melt 25 μg for 28 days to complete part 1 of the study. Participants will continue on this dose in study part 2 for between 1-6 months (until the database for part 1 is locked and treatment is unblinded).
• Experimental: Participants will take desmopressin melt 50 μg for 28 days to complete part 1 of the study. Participants will continue on this dose in study part 2 for between 1-6 months (until the database for part 1 is locked and treatment is unblinded).
• Experimental: Participants will take desmopressin melt 100 μg for 28 days to complete part 1 of the study. Participants will continue on this dose in study part 2 for between 1-6 months (until the database for part 1 is locked and treatment is unblinded).

Inclusion Criteria

1. Written informed consent prior to the performance of any study-related activity.
2. Patients 18 years and older with an average of ≥ 2 nocturnal voids per night as determined by a 3 day voiding diary

Exclusion Criteria:

Males:

1. Clinical suspicion of bladder outlet obstruction and/or urine flow < 5 ml/s. If medical history and/or physical examination suggest bladder outlet obstruction, uroflowmetry should be performed to confirm the diagnosis

2. Surgical treatment for bladder outlet obstruction/benign prostatic hyperplasia performed within the past 6 months

   Females:

3. Pregnancy. Females of reproductive age must have documentation of a reliable method of contraception.
4. Use of pessary for pelvic prolapse

5. Unexplained pelvic mass

   Males and Females:

6. Clinical suspicion of urinary retention and/or post void residual volume > 150 ml. If medical history and/or physical examination suggest urinary retention, post void bladder ultrasound or catheterization should be performed to confirm the diagnosis
7. Current or past urologic malignancy (e.g. bladder cancer, prostate cancer, etc.)
8. Clinical evidence of current genito-urinary tract pathology (e.g. infection, stone, tumor, etc.)
9. Neurogenic detrusor activity (previously known as detrusor hyperreflexia)
10. Suspicion or evidence of cardiac failure
11. Uncontrolled hypertension
12. Uncontrolled diabetes mellitus
13. Renal insufficiency. Serum creatinine must be within normal limits.
14. Active hepatic and/or biliary disease. AST or ALT should not be >2 times the upper limit of normal. Total bilirubin should not be > 1.5 mg/dL.
15. Hyponatremia. Serum sodium level must be within normal limits
16. Syndrome of Inappropriate ADH secretion
17. Diabetes insipidus (urine output > 40 ml/kg over 24 hours) as determined by the 3 day voiding diary
18. Psychogenic or habitual polydipsia
19. Obstructive sleep apnea
20. Hyperkinetic limb disorders (e.g. restless leg syndrome) known to impair sleep Other
21. Known alcohol or substance abuse
22. Work or lifestyle potentially interfering with regular night-time sleep (e.g. shift workers)
23. Previous desmopressin treatment for nocturia
24. Psychiatric condition, mental incapacity or language barrier which, in the judgment of the investigator, would impair patient participation in the trial

Concomitant Medications

The following medications are permitted provided that the subject has been on a stable dose for the 3 months prior to the screening date (i.e. treatment has not been initiated or discontinued and there has been no change in dose):

• Alpha-blockers: Cardura (doxazosin); Flomax (tamsulosin); Hytrin (terazosin); Uroxatral (alfuzosin)
• 5 alpha-reductase inhibitors: Avodart (dutaseride); Proscar (finasteride)
• Antispasmodic, anticholinergic, antimuscarinic therapy for overactive bladder: Detrol, Detrol LA (tolterodine); Ditropan, Ditropan XL (oxybutynin); Enablex (darifenacin); Levsin(hyoscyamine); Oxytrol transdermal (oxybutynin); Sanctura (trospium); Vesicare (solifenacin)
• Sedative/hypnotic medications for sleep disorders
• Selective serotonin and mixed norepinephrine/serotonin reuptake inhibitors: Celexa (citalopram); Cymbalta (duloxetine); Effexor (venlafaxine); Lexapro (escitalopram); Paxil(paroxetine); Prozac (fluoxetine); Zoloft (sertraline)
• Chronic use of non-steroidal anti-inflammatory agents
• Diabinese (chlorpropamide)
• Carbamazepine (carbatrol/tegretol)
• Amiodarone

The following medications are excluded:

• Diuretics
• Any other investigational drug within 30 days of screening