VASOPRESSIN (ADH/antidiuretic hormone) + VAPTANS

Question 1

vasopressin → drug names:

Answer 1

1. desmopressin
2. terlipressin
3. felypressin

Question 2

action of V-receptors:

Answer 2

1. V1 = vascular smooth muscle cells → mediate vasoconstriction & platelet aggregation
2. V2 = renal tubule cells → antidiuresis through increased water permeability & water resorption in collecting tubules
3. V2-like = in vessels → mediate release of coagulation factor VIIIc & vW factor
4. V3 = in ant. pituitary → promote release of ACTH

Question 3

vasopressin → mechanism of action:

Answer 3

antidiuretic + vasopressor

Question 4

vasopressin → indications:

Answer 4

1. pituitary diabetes insipidus
2. management of cardiac arrest
3. bleeding esophageal varices & colonic diverticular bleeding
4. hemophilia A
5. von Willebrand disease
6. bleeding (terlipressin)
7. local anesthetics (felypressin)
8. noctural enuresis (desmopressin)

Question 5

vasopressin → side effects:

Answer 5

1. vasopressin (but not desmopressin) → can cause vasoconstriction
2. overdosage → can result in hyponatremia
3. water intoxication
4. abdominal pain
5. tremor
6. vertigo

Question 6

with actually IS VAPTANS?!

Answer 6

vaptans = nonpeptide vasopressin receptor antagonists (VRA)

Question 7

VRA → drug names:

Answer 7

1. conivaptan (V1 & V2 antagonist)

2. tolvaptan (V2 antagonist) → the first ORAL VRA

Question 8

VRA → mechanism of action:

Answer 8

BLOCK V-receptors → V1A, V1B & V2

1. dilute urine
2. increase free water clearance
3. raise serum Na

Question 9

VRA → indication:

Answer 9

HYPONATREMIA → in pat. with CHF, liver cirrhosis, SIADH