Desmopressin

Drug Information: Desmopressin

Desmopressin is a synthetic analog of vasopressin, a naturally occurring antidiuretic hormone. It is used primarily for its antidiuretic properties, meaning it helps to reduce the amount of urine produced by the kidneys. Desmopressin works by binding to V2 receptors in the kidneys, increasing water reabsorption and thus decreasing urine output. It is available in various formulations, including oral tablets, nasal spray, and injection.

Category

Hormones – Other endocrine medications

Mechanism of Action

Desmopressin is a synthetic analog of vasopressin, also known as antidiuretic hormone (ADH). It acts as a selective V2 receptor agonist. V2 receptors are primarily located in the kidneys, specifically in the principal cells of the collecting ducts. When desmopressin binds to these V2 receptors, it activates adenylate cyclase, increasing intracellular cyclic AMP (cAMP) levels. This, in turn, leads to the insertion of aquaporin-2 water channels into the apical membrane of the principal cells. Aquaporin-2 channels allow water to move from the tubular fluid back into the bloodstream, increasing water reabsorption and reducing urine volume. Unlike vasopressin, desmopressin has minimal V1 receptor activity. V1 receptors are found in blood vessels and mediate vasoconstriction; the lack of V1 activity in desmopressin reduces the risk of increased blood pressure. The antidiuretic effect of desmopressin is significantly more potent and longer-lasting than that of vasopressin, making it suitable for managing conditions involving water imbalance.

Clinical Uses

Desmopressin is clinically used in several conditions related to fluid balance and bleeding disorders. Its primary use is in the treatment of central diabetes insipidus, a condition characterized by the body’s inability to regulate fluid balance due to a deficiency in vasopressin production. Desmopressin helps reduce excessive thirst and urination associated with this condition. It is also used to manage nocturnal enuresis (bedwetting) in children, reducing nighttime urine production. Another use is in the management of bleeding disorders such as mild hemophilia A and von Willebrand disease. Desmopressin stimulates the release of von Willebrand factor and factor VIII from endothelial cells, which improves blood clotting. Furthermore, it can be used to treat thrombocytopenia (low platelet count) and platelet dysfunction in some patients. The specific formulation and route of administration (oral, nasal, injection) depend on the condition being treated and the patient’s individual needs.

Dosage

Central Diabetes Insipidus:
* Oral:
* Adults: Initial dose is typically 0.1 mg two to three times daily. Dosage may be adjusted based on response, usually ranging from 0.1 mg to 1.2 mg daily in divided doses.
* Pediatrics: Starting dose is 0.05 mg two to three times daily. Dosage adjustments are made based on response, generally ranging from 0.1 to 0.8 mg daily in divided doses.
* Nasal Spray:
* Adults: 10-40 mcg (0.1-0.4 mL) daily, administered as a single dose or divided into two or three doses.
* Pediatrics (age 4 and older): 10-20 mcg (0.1-0.2 mL) daily, usually in one or two doses.
* Injection (IV/Subcutaneous):
* Adults: 1-4 mcg daily in divided doses.
* Pediatrics: 0.1-1 mcg daily in divided doses.

Nocturnal Enuresis (Bedwetting):
* Oral:
* Pediatrics (6 years and older): 0.2 mg at bedtime. If this dose is ineffective, it may be increased to 0.4 mg.
* Nasal Spray:
* Pediatrics (6 years and older): 20 mcg (0.2 mL) at bedtime.

Hemophilia A and von Willebrand Disease:
* Injection (IV):
* Adults and Pediatrics: 0.3 mcg/kg body weight, diluted in 50 mL of normal saline and infused slowly over 15-30 minutes.

Dosage adjustments should be made under the supervision of a healthcare professional based on individual patient response and monitoring of urine output and serum sodium levels.

Indications

Common indications for Desmopressin include:
* Central Diabetes Insipidus
* Nocturnal Enuresis (Bedwetting)
* Management of bleeding in mild Hemophilia A
* Management of bleeding in von Willebrand Disease
* Management of thrombocytopenia (low platelet count) and platelet dysfunction

Contraindications

Desmopressin is generally contraindicated in the following conditions:
* Known hypersensitivity to desmopressin or any of its components.
* Moderate to severe renal impairment (creatinine clearance less than 50 mL/min).
* Hyponatremia (low sodium levels in the blood) or a history of hyponatremia.
* Polydipsia (excessive thirst) of habitual or psychogenic origin.
* Syndrome of Inappropriate Antidiuretic Hormone Secretion (SIADH).
* Uncontrolled hypertension.
* During intercurrent illnesses, especially those with fluid and electrolyte imbalances (e.g., gastroenteritis).

FAQ

Q: What is Desmopressin used for?
A: Desmopressin is used to treat central diabetes insipidus, nocturnal enuresis (bedwetting), and certain bleeding disorders like mild hemophilia A and von Willebrand disease.

Q: How does Desmopressin work?
A: It mimics the action of vasopressin (antidiuretic hormone), increasing water reabsorption in the kidneys and reducing urine production. It also promotes the release of clotting factors to help control bleeding.

Q: What are the common side effects of Desmopressin?
A: Common side effects include headache, nausea, nasal congestion (if using nasal spray), and hyponatremia (low sodium levels).

Q: How should Desmopressin be taken?
A: Desmopressin is available in oral tablets, nasal spray, and injection forms. The specific dosage and route depend on the condition being treated and should be determined by a healthcare professional.

Q: Can Desmopressin cause hyponatremia?
A: Yes, Desmopressin can cause hyponatremia, especially if fluid intake is not appropriately restricted. Symptoms of hyponatremia include headache, nausea, confusion, and, in severe cases, seizures.

Q: What should I do if I miss a dose of Desmopressin?
A: If you miss a dose, take it as soon as you remember, unless it is almost time for your next dose. In that case, skip the missed dose and continue with your regular dosing schedule. Do not double the dose to catch up.

Q: Are there any specific precautions I should take while using Desmopressin?
A: It’s essential to restrict fluid intake while taking Desmopressin to avoid hyponatremia. Also, inform your healthcare provider about any other medications you are taking, as drug interactions can occur.

Q: Can children use Desmopressin?
A: Yes, Desmopressin is used in children, particularly for nocturnal enuresis. However, the dosage needs to be carefully determined and monitored by a healthcare professional.