Enurex

Approved Indications:

• Diabetes Insipidus (Central/Neurogenic): Replacement therapy for vasopressin deficiency, in both adults and children.
• Nocturnal Enuresis: Treatment of primary nocturnal enuresis in children (typically ≥ 6 years) when non‑pharmacologic measures are insufficient.
• Bleeding Disorders:
• Treatment and prevention of bleeding in mild to moderate hemophilia A and von Willebrand disease (type 1) under surgical or minor invasive procedures or spontaneous bleeding episodes.
• Uraemic Bleeding: To control bleeding in patients with mild renal failure and uremic bleeding diathesis (off-label or local approval).

Clinically Accepted Off-label Uses:

• Mild von Willebrand disease type 2A or 2M (selected cases under specialist care).
• Platelet function disorders, hyporeninemic hypoaldosteronism, and certain platelet aggregation defects.

Central Diabetes Insipidus:

• Intranasal Spray (Adults): 10–40 μg once or twice daily.
• Oral Tablets: 0.1–0.8 mg per dose, divided into 2–3 doses per day.
• SC/IV Injection (Emergency): 4 μg (or 0.4 μg/kg) as a single dose.

Nocturnal Enuresis (Children 6+ years):

• Oral 0.2 mg tablet, taken approximately 1 hour before bedtime; maximum single dose 0.4 mg. Limit fluid intake until next morning.

Hemophilia A / von Willebrand Disease:

• IV or SC 0.3 µg/kg body weight, given 30–60 minutes before procedure. May repeat dose after 12 hours if needed (up to 2 doses/day for 1–3 days).

Uraemic Bleeding:

• IV 0.3 µg/kg/day for 1–3 consecutive days pre- and post-procedure.

Special Populations:

• Elderly: Same doses; monitor fluid balance and renal function.
• Renal Impairment: Use lowest effective dose; reduce frequency.
• Hepatic Impairment: No specific adjustment.

Desmopressin is a synthetic analogue of human antidiuretic hormone (ADH, vasopressin), modified to enhance duration and reduce vasoconstrictor effects. It binds selectively to renal V₂ receptors in the collecting ducts, promoting aquaporin-2 channel insertion and increasing water reabsorption to concentrate urine. Additionally, it induces release of von Willebrand factor and factor VIII from endothelial stores, enhancing platelet adhesion and clotting—making it effective in mild bleeding disorders.

• Absorption:
• Oral bioavailability of tablets ~0.1–0.2%; intranasal ~3–5%; IV/SC direct.
• Distribution:
• Volume of distribution ~0.2 L/kg; minimal plasma protein binding.
• Metabolism:
• Minimal; mostly excreted unchanged.
• Half-life:
• IV: ~1.5 hours; nasal: ~4–8 hours; oral: ~2–3 hours.
• Excretion:
• Excreted unchanged in urine; clearance prolonged in renal impairment.

• Pregnancy:
• Category B. Animal studies show no harm; human data limited. Consider use in gestational DI or bleeding only if benefits justify risks.
• Lactation:
• Excreted in breast milk in small amounts; generally considered safe. Monitor infant for signs of fluid retention.

• Primary Class: Vasopressin analogue
• Subclass: Antidiuretic hormone replacement / hemostatic agent

• Known hypersensitivity to desmopressin or excipients.
• Severe renal impairment where fluid restriction is impossible.
• Hyponatremia or uncontrolled fluid intake.
• Hypertension unresponsive to therapy in IV use.
• Type 1 von Willebrand disease (since ineffective).

• Hyponatremia & Water Intoxication: Monitor serum sodium; advise strict fluid restriction during therapy.
• Seizures: Possible with severe hyponatremia—monitor symptoms such as headache, confusion, seizures.
• Volume Overload: Particularly in elderly or cardiac disease—monitor weight and blood pressure.
• Renal Impairment: Risk of accumulation and water retention.
• Thromboembolism: Rare risk in patients with cardiovascular disease when used for bleeding.
• Excessive Vascular Action: Minimal in usual doses, but monitor blood pressure when given IV/SC.

Common:

• Headache
• Facial flushing
• Nasal congestion (with intranasal spray)
• Mild gastrointestinal disturbance

Less Common:

• Hyponatremia (especially in children and adults on fluid overload)
• Edema or weight gain
• Mild hypertension (IV use)

Rare/ Serious:

• Water intoxication leading to seizures or coma
• Thromboembolic events (rare)
• Allergic reactions (rash, urticaria)

• Carbamazepine, chlorpropamide, SSRIs, chlorpromazine: May potentiate hyponatremia risk.
• NSAIDs: Can enhance antidiuretic effect.
• Lithium, loop diuretics: May alter sodium balance—monitor serum sodium.
• No CYP450 interactions.

• 2022–2024 Endocrine Society Guidelines: Emphasize water restriction and sodium monitoring to prevent hyponatremia in DI patients.
• Hematology Guidelines (WFH, ISTH): Recommend desmopressin as first-line agent in mild hemophilia A and type 1 von Willebrand disease for minor procedures.
• Clarification that nasal formulations may deliver variable doses—oral tablets preferred in consistent long-term use.

• Injectable Solution: Store at 2°C–8°C (36°F–46°F); protect from light; do not freeze. Stable at room temperature (up to 25°C) for limited time per manufacturer.
• Nasal Spray: Store at 2°C–25°C (36°F–77°F); discard after use period.
• Oral Tablets: Store at 20°C–25°C (68°F–77°F); protect from moisture; keep in tightly closed container.
• Handling: Tablets and nasal sprays require no special handling. Keep all forms out of reach of children.