Nocdurna (Desmopressin)

Desmopressin acts on the antidiuretic hormone pathway to control excessive urine production in several disorders.

• Nocturnal enuresis (children and adolescents): reduces nighttime urine volume, helping achieve dry nights.
• Central diabetes insipidus: replaces deficient vasopressin activity, decreasing polyuria and polydipsia.
• Hemophilia A (adjunct therapy): raises plasma factor VIII levels, improving hemostasis during minor procedures.
• von Willebrand disease (adjunct therapy): increases von Willebrand factor release, enhancing platelet adhesion for bleeding control.

• Desmopressin is a synthetic analogue of the natural hormone vasopressin that selectively binds to V2 receptors located on the basolateral membrane of renal collecting‑duct cells. Activation of V2 receptors stimulates adenylate cyclase, raising intracellular cyclic AMP, which promotes the insertion of aquaporin‑2 water channels into the apical membrane. The resulting increase in water reabsorption concentrates urine and reduces overall urine output.

Desmopressin may be associated with a range of adverse reactions, varying from mild to severe.

Common Side Effects

• Headache: mild to moderate pain often reported after dosing.
• Nausea: transient stomach upset that usually resolves without intervention.
• Facial flushing: brief redness of the skin, particularly on the cheeks.
• Dry mouth: reduced salivation leading to mild oral discomfort.
• Abdominal cramps: intermittent stomach pain that is usually self‑limiting.

Serious or Rare Side Effects

• Hyponatraemia: low blood sodium that can lead to confusion, seizures, or coma.
• Water intoxication: excessive water retention causing rapid weight gain and edema.
• Allergic reactions: rash, itching, or swelling that may require medical attention.

When prescribing desmopressin, clinicians should observe several safety measures to minimize risk.

• Monitor fluid balance: assess daily fluid intake and output to prevent overload.
• Check serum sodium: regular laboratory evaluation to detect hyponatraemia early.
• Adjust dose in renal impairment: reduce dosage or increase monitoring in patients with reduced kidney function.
• Use caution in hypertension: avoid excessive fluid retention that may raise blood pressure.
• Avoid in uncontrolled hyponatraemia: contraindicated in patients with already low sodium levels.
• Store at room temperature: keep tablets in the original container, protect from moisture and heat.

Desmopressin can interact with other medicines, altering its efficacy or safety profile.

Major Interactions (Avoid)

• Vaptans (e.g., tolvaptan, conivaptan): opposite action on V2 receptors may negate therapeutic effect.
• Carbamazepine: induces hepatic enzymes that increase desmopressin metabolism, reducing its activity.

Moderate Interactions (Monitor Closely)

• Loop diuretics: enhance water loss and may exacerbate hyponatraemia when combined.
• Thiazide diuretics: increase risk of low sodium levels, requiring close electrolyte monitoring.
• NSAIDs: may reduce renal prostaglandin synthesis, potentiating water retention and hyponatraemia.