Desmopressin – Cardiology MCQ – Answer

Desmopressin – Cardiology MCQ – Answer Which of the following is not an adverse effect of desmopressin used in the treatment of postural hypotension? – Correct answer: d) Nocturnal diuresis Suppression of nocturnal diuresis is an important mechanism of action of low dose desmopressin. Desmopressin is a synthetic analogue of the naturally occuring pituitary hormone which is 8-arginine vasopressin (anti diuretic hormone, ADH). The drug acts on vasopressin receptor type 2 in the renal collecting ducts and increases water reabsorption, causing water retention. The synthetic molecule has only minimal action on vasopressin receptor type 1 on blood vessels. Hence the effect on vasoconstriction is minimal at antidiuretic doses [1]. Desmopressin can be administered either as a nasal spray or oral tablet. Very low doses of 5 micrograms may be enough to suppress nocturnal polyuria in patients with orthostatic hypotension. Nocturnal polyuria and consequent volume depletion is likely to cause early morning syncope or syncope while going to toilet at night. Patients with orthostatic hypotension due to central neurodegenerative disorders like multiple system atrophy have loss of vasopressin producing neurons in the suprachiasmatic nucleus of hypothalamus [1]. Normal circadian rhythm of arginine vasopressin secretion ensures higher antidiuretic effect at night which ensures that there is no nocturnal polyuria permitting good sleep. Loss this circadian pattern leads to noctu...
Source: Cardiophile MD - Category: Cardiology Authors: Tags: Cardiology MCQ DM / DNB Cardiology Entrance Source Type: blogs