Question

Desmopressin is preferred over vasopressin because desmopressin -

• A. More potent
• B. More selective for V1 receptor
• C. Has little vasoconstrictor activity
• D. a and c

Hint:

Desmopressin is V2 selective, more potent, and barely touches vessels.

Answer 1

The Correct Option is D

Step 1: Desmopressin (DDAVP) is a synthetic analogue of vasopressin used in central diabetes insipidus, nocturnal enuresis and mild haemophilia A or von Willebrand disease.

Step 2: It is selective for V2 receptors (antidiuretic action) and has very little action on V1 receptors, so it produces little vasoconstriction. This avoids the pressor and ischaemic effects seen with vasopressin.

Step 3: Desmopressin is also longer acting and roughly 12 times more potent than vasopressin as an antidiuretic.

Step 4: So both the greater potency (option a) and the minimal vasoconstrictor activity (option c) are correct. Option b is wrong because desmopressin is V2 selective, not V1 selective. Hence the answer is a and c.