L32- Hypothalamic and Pituitary Hormones (posterior) Flashcards Preview

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Flashcards in L32- Hypothalamic and Pituitary Hormones (posterior) Deck (10)
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-acts on (1) type receptors in order to stimulate (2)
-(3) effect at low doses
-(4) effect at high doses

1- G-protein coupled receptors
2- PG release + LT release --> augments uterine contraction

3- inc force, frequency of contractions (uterine, breast-feeding)

4- sustained contractions, weak antidiuretic / pressor activity (vasopressin receptor activation)


list the clinical effects of Oxytocin

Labor Induction (IV): when early vaginal delivery is required; Rh issue, maternal DM, pre-eclampsia, ruptured membranes

Augments Normal Labor (IV): when labor is protracted / displays arrest disorder

Control of uterine hemorrhage (IM)


Oxytocin AEs

severe toxicity is rare
-excess stimulation of uterine contractions --> fetal distress, placental abruption, uterine rupture

-inadvertent activation of vasopressin receptors --> excess fluid retention / water toxicity => hyponatremia, HF, seizures, death

-Bolus injections leading to hypotension --> administer IV as dilute solution at controlled rate


Oxytocin contraindications

-fetal distress
-abnormal fetal presentation
-cephalopelvic disproportion
-uterine rupture predisposition


Oxytoxin Antagonist = (1), and is used for (2)

Atosiban- Tx for preterm labor (NOT in the USA)


compare the ADH agonists


-Desmopressin: long-acting synthetic analog, minimal V1 activity ----- 4000:1 antidiuretic to vasopressor activity ratio


describe the direct MOA of ADH agonists

-activates 2 G-protein coupled receptors

V1R: vascular smooth muscle --> contraction (vasopressin > desmopressin)

V2R: renal tubule cells --> inc water permeability and water reabsorption (desmopression > vasopressin)


ADH agonist clinical applications

drugs of choice for diabetes insipidus (mainly central DI)

Vasopressin: esophageal variceal bleeding, colonic diverticular bleeding

Desmopressin: coagulopathy Tx in Hemophilia A and VWD


ADH agonist AEs

-HAs, nausea, abdominal cramps, allergic reactions

-OD --> hyponatremia, seizures


ADH antagonist = (1), affects (2) receptors. used for (3)

1- Conivaptan

2- V1R (pressor), V2R (antidiuretic)

3- hyponatremia due to elevated vasopressin