Desmopressin

1. Indications
   1. Diabetes Insipidus
   2. Control of Hemophilia A related bleeding
   3. Von Willebrand's Disease
   4. Primary Nocturnal Enuresis
2. Mechanism
   1. Synthetic ADH replacement hormone (anologue of Vasopressin)
   2. Potent antidiuretic
   3. No vasopressor activity
   4. Urine volume decreases by resorbing water at distal renal tubules
3. Pharmacokinetics
   1. Duration of action: 12 hours
4. Dosing: Nocturnal Enuresis
   1. General
      1. If effective, may continue for 3-6 months
      2. Maintain dose for 4-6 weeks and then slowly taper off over 6 months
         1. Discontinue slowly (e.g. 10 mcg/month)
         2. Reduces risk of relapse
      3. Consider in combination with Bed-Wetting Alarm or Oxybutynin
   2. Desmopressin Intranasal
      1. Not recommended due to risk of water intoxication
      2. Initial: 5 mcg spray each nostril qhs
      3. Increase as needed up to 20 mcg each nostril qhs
   3. Desmopressin Oral
      1. Initial: 0.2 mg PO qhs
      2. Use lowest effective dose
      3. Increase as needed to 0.6 mg at bedtime
5. Dosing: General
   1. Nasal Spray: 5-20 mcg daily to twice daily
      1. Intranasal 5 mcg equivalent to 0.1 mg PO
   2. Oral Tablet: 0.1 mg PO daily to twice daily
6. Adverse Effects
   1. Nasal irritation or Epistaxis with nasal spray
   2. Behavior changes
      1. Aggressive behavior
      2. Nightmares
   3. Nocturia
      1. Administer at night to reduce nocturia
   4. Water retention and Hypernatremia (water intoxication)
7. Efficacy: Nocturnal Enuresis
   1. Most effective in over age 8-9 years (60-70% respond)
   2. Also more effective if only a few wet nights and normal Bladder capacity
   3. High relapse rate (>80%); Reduced if slowly tapered - see doing above
8. Disadvantages
   1. Very Expensive
9. References
   1. Tullus (1999) Acta Paediatr 88:1274-8
   2. Kruse (2001) BJU Int 88:572-6
   3. Robson (2007) J Urol 178: 24-30