Overview
Desmopressin is a synthetic analogue of the antidiuretic hormone vasopressin. It is primarily used to treat nocturnal enuresis (bedwetting), diabetes insipidus, and certain bleeding disorders.

Mechanism of Action
It binds to V2 receptors in the renal collecting ducts, increasing water reabsorption and thereby reducing urine production. For bleeding disorders, it stimulates the release of von Willebrand factor and Factor VIII from endothelial cells.

Dosage and Administration
Available as oral tablets, sublingual melts, and nasal sprays. For bedwetting, it is taken orally shortly before bedtime. Fluid intake must be restricted from 1 hour before until 8 hours after administration to prevent water intoxication.

Side Effects
Headache, nausea, and mild abdominal pain are common. The most serious potential side effect is hyponatremia (low blood sodium levels) due to water retention, which can lead to seizures or coma if fluid intake is not properly managed.

Contraindications
Contraindicated in patients with habitual or psychogenic polydipsia (excessive thirst), known hyponatremia, or moderate to severe renal impairment. It should be used cautiously in patients with cardiovascular disease.