Desmopressin emulates the actions of endogenous human ADH (refer to Pharmacology section above). Desmpressin is a structural analogue of ADH modified by deamination of 1-cysteine and substitution of 8-L-arginine by 8-D-arginine. Compared to natural ADH, desmopressin elicits a great antidiuretic response on weight basis.
Desmopressin is a synthetic analogue of the natural antidiuretic hormone (ADH or vasopressin) that is produced by the hypothalamus and stored in the posterior pituitary gland. The main function of ADH is to regulate extracellular fluid volume in the body. ADH secretion is stimulated by angiotensin II, linking it to the renin-angiotensin-aldosterone system (RAAS). ADH stimulates water reabsorption in the kidneys by causing the insertion of aquaporin-2 channels on the apical surface of cells of the DCT and collecting tubules. It also causes vasoconstriction through its action on vascular smooth muscle cells of the collecting tubules. The efficacy of desmopressin for managing bleeds in patients with hemophilia A or von Willebrand’s disease Type I arises from its ability to elicit dose-dependent increases in plasma factor VIII (antihemophilic factor), plasminogen activator, and to a lesser extent, factor VIII-related antigen and ristocetin cofactor activities; these changes improve blood clotting.
Metabolic fate unknown. Is not affected by liver microsomal cytochrome P450 enzymes.
Overdose may lead to increased duration of action and lead to symptoms such as fluid retention, headaches, abdominal cramps, nausea, and facial flushing. Adverse effects include headache, nausea, abdominal pain, facial flushing, dizziness, dry mouth, and hyponatremia. Nasal congestion and rhinitis have been reported with nasal spray formulations.