Desmopressin Dosage for Primary Nocturnal Enuresis
For primary nocturnal enuresis, start with oral desmopressin tablets 0.2-0.4 mg taken at least 1 hour before bedtime, with the option to start at the higher dose and taper down if effective, or start low and titrate up to a maximum of 0.6 mg based on response. 1
Dosing by Formulation
Oral Tablets (Standard Formulation)
- Initial dose: 0.2-0.4 mg taken at least 1 hour before sleep 1
- Maximum dose: 0.6 mg nightly 2
- Timing is critical because maximum renal concentrating effect occurs 1-2 hours after administration 1
- Dosing is not influenced by body weight or age 1
Oral Melt Tablets (Lyophilisate)
- Dose: 120-240 μg taken 30-60 minutes before bedtime 1, 3
- This formulation requires shorter lead time before sleep compared to standard tablets 1
- Not yet available in the United States 1
Dosing Strategy Options
You have two equally valid approaches 1:
- Start high and taper down: Begin with 0.4 mg and reduce to 0.2 mg if good response is achieved
- Start low and titrate up: Begin with 0.2 mg and increase by 0.2 mg increments every 2 weeks until dryness is achieved or maximum dose (0.6 mg) is reached 2
Recent evidence from a Chinese cohort suggests that 86% of responders achieved success with only 0.2 mg, and low-dose responders were significantly more likely to achieve complete response without dose escalation (OR=9.683) 4. This supports starting at 0.2 mg and only increasing if inadequate response after 2 weeks.
Response Assessment
- Anti-enuretic effect is seen immediately - if no response within 2 weeks at a given dose, consider increasing 1
- Response rates range from 10-65% depending on patient selection 1, 3
- Complete or near-complete response (0-2 wet nights) occurs in 24-33% of patients at doses of 0.4-0.6 mg 5
- At least 50% reduction in wet nights occurs in approximately 44% of patients even at lower doses of 0.2-0.4 mg 2
Critical Safety Requirements
Fluid Restriction (Non-Negotiable)
- Evening fluid intake must be limited to 200 ml (6 ounces) or less with NO drinking until morning 1, 3, 6
- This restriction is mandatory to prevent water intoxication with hyponatremia and convulsions 1, 3
- Polydipsia is an absolute contraindication to desmopressin treatment 1, 3
Formulation Safety
- Avoid nasal spray formulations - they carry higher risk of hyponatremia and the enuresis indication has been removed in many countries 1, 3
- Oral formulations are strongly preferred 1
Monitoring Requirements
- Schedule regular short drug holidays to assess whether medication is still needed 1, 3
- If intercurrent illness occurs during treatment, monitor electrolytes due to risk of water intoxication 1
Optimal Patient Selection
Desmopressin works best in children with 1:
- Nocturnal polyuria (nocturnal urine production >130% of expected bladder capacity for age)
- Normal bladder reservoir function (maximum voided volume >70% of expected bladder capacity for age)
- Patients in whom alarm therapy has failed or is unlikely to be followed
Maintenance Approach
Once effective dose is established, families can choose 1:
- Daily medication with regular drug holidays to reassess need
- Intermittent use before important nights only (camps, sleepovers)
Long-term administration has not been associated with depression of endogenous ADH secretion 1, making extended use safe when needed.
Alternative Dosing for Older Studies
Older literature (particularly from 2004) suggested doses of 0.2-0.6 mg for tablets 1, which aligns with current recommendations. Some studies in adolescents and adults used 200-400 μg with good efficacy 7, 8, supporting the lower end of the dosing range as often sufficient.