Arginine Vasopressin (AVP) Flashcards Preview

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Flashcards in Arginine Vasopressin (AVP) Deck (27):
1

What are the trade names of Vasopressin?

Pitressin, ADH

2

What formal drug class is Vasopressin in?

Exogenous antidiuretic peptide and vasopressor

3

What are the clinical uses of Vasopressin?

-used in the treatment of diabetes insipidus (non-nephrogenic)
-in the evaluation of the urine-concentrating abilities of the kidneys after administration of fluorinated volatile anesthetics
-in the management of uncontrolled hemorrhage from esophageal varices
-as an alternative to epinephrine in CPR
-as an adjunct vasopressor in hemorrhagic or septic shock

4

What is the MOA of Vasopressin as a vasoconstrictor?

-Acts as a vasopressor by stimulating V1a receptors on vascular smooth muscle, glomerular mesangial cells, and the vasa recta
-it is an extremely potent vasoconstrictor of the glomerular EFFERENT arteriole, while having little effect on the afferent arteriole, maintaining effective glomerular filtration pressure
-It also promotes hemostasis by increasing von Willebrand factor and factor VIII
-In addition, causes peristalsis by directly stimulating GI smooth muscle

5

What is the MOA of Vasopressin as an antidiuretic?

-activates V2 receptors on the basolateral cell membrane of the renal collecting ducts, which induces water reabsorption and urine dilution
-through activation of G-protein-coupled adenyl cyclase, ATP is converted to cyclic adenosine monophosphate (cAMP). This in turn activates a protein kinase that causes preformed vesicles containing aquaporin-2 water channels to fuse with the apical cell membrane to allow reabsorption of water

6

How is Vasopression metabolized?

Metabolism by tissue peptidases, 33% removed by the kidney

7

What is the e 1/2 time of Vasopressin?

10-20min from enzymatic breakdown in tisues, especially in the kidneys

8

What is the onset of action of nasal Vasopressin?

1 hour

9

What is the duration of action for nasal vasopressin?

3-8 hours; IM/SC 2-8hrs

10

Why cant Vasopressin be administered orally?

Rapid inactivation by trypsin

11

What are the Cardiovascular side effects of Vasopressin?

-IV route may cause coronary artery spasm
-Vasoconstriction and increased SBP occur with doses much larger than those administered for DI, which may cause facial pallor
-in small doses, may produce selective coronary artery vasoconstriction, causing angina and myocardial ischemia

12

What are the GI side effects of Vasopressin?

-Stimulation of GI smooth muscle may cause increased peristalsis, N/V, abdominal pain and the uterus may be stimulated as well

13

As a side effect to Vasopressin, what can happen to platelet count? what is the mechanism for this?

a decreased platelet count has been attributed to AVP via V1 receptors

14

What are the dermatological side effects of Vasopressin?

Urticaria
Anaphylaxis
Diaphoresis

15

What are the CNS side effects of Vasopressin?

Pounding of the head
Vertigo
Fever

16

What are the neuromuscular side effects of Vasopressin?

Tremor

17

What are the Respiratory side effects of Vasopressin?

Bronchial Constriction

18

What are the contraindications to Vasopressin?

Hypersensitivity to AVP or any component of the formulation

19

What are the drug interactions between Vasopressin and NSAIDS and Carbamazapine?

Increase AVP effects

20

What is the drug interaction that occurs between Vasopressin and Lithium, Colchicine, and Vinca alkaloids?

Lithium, Colchicine and Vinca Alkaloids decrease AVP effects

21

What happens when Demeclocycline and Vasopressin are administered together?

Demeclocycline counteracts the action of ADH and can be used for hyponatremia caused by excessive AVP

22

What is the dosage of Vasopressin for Diabetes Insipidus?

During surgery, 100-200mU/hr continuous IV

23

What is the dosage of Vasopressin used for GI hemorrhage?

IV: dilute in NS or D5W to 0.1-1unit/mL
Initial: 0.2-0.4 units/min, then titrate dose as needed, if bleeding stops. Continue for 12hr, taper off over 24-48hr

24

What is the dosage of Vasopressin used for Esophageal Varices?

20units IV over 5min

25

What is the dosage of Vasopressin used for refractory Cardiac Arrest?

40units IV push

26

What is the dosage of Vasopressin used for Hemorrhagic and Septic Shock?

IV gtt: 0.01-0.1 units/min
Doses> 0.05units/min may have more cardiovascular side effects
Most cases have used 0.04units/min as a fixed dose

27

What type of endogenous thing is AVP? where is it normally synthesized? What usually causes release in the body?

an Endogenous 9-amino-acid peptide hormone; normally synthesized in the supraoptic and paraventricular nuclei of the anterior hypothalamus. It undergoes neuroaxial transport to the posterior pituitary gland, where it is stored in granules. Neural stimulation of the cell bodies in the hypothalamus from baroreceptor or osmotic receptor stimulation triggers exocytosis of AVP from the terminal vesicles into the circulation