Pituitary Flashcards
Desmopressin- what is it? What does it treat? How does it work? How is it usually adminstered? CARE? What is its sister called and what does it treat?
It is a synthetic version of vasopressin, which acts as a selective vasopressin receptor petidergic agonist. It is used to treat cranial diabetics insipidus. By stimulating V2 receptors on renal cortical collecting ducts, it stimulates the adenyl cyclase–> increased cAMP–> activated PKA. This increases the formation and insertion of AQP2 into the apical membrane (of tubule lumen), hence increasing water reabsorption form the collecting duct of the nephron. It’s usually admisntered nasally and CARE- remind patients to limit fluid intake.
It’s sister is called terlipressin which is a V1 receptor agonist- used as a vasoconstrictor and GI medication.
Bendroflumethiazide- what is it? What does it treat? Mechanism (6)
It is a thiazide drug, used to treat nephrogenic diabetes insipidus. Mechanism: 1) it inhinits Na/Cl transport in the DCT of the nephron. 2) This decreases blood volume. 3) In response, there is a compsensaorty increased Na reabsorption from the PCT. 4) This also increases H20 reabsorption form the PCT. 5) So decreased fluid volume reaches the collecting duct. 6) So decreased urine volume.
Demeclocyline- what is it used to treat? How does it work? (brief)
Used to treat SIADH. Works by inducing nephrogenic diabetes insipidus to reduce renal water reabsorption.
Vaptans- what are they? What are they used to treat? Mecahansim? Problem?
What does aqauresis mean?
Non-competitive V2 receptor antagonist. Used to treat SIADH. By blocking V2 receptors, prevent the insertion of AQP2 into apical membrane of nephron (tubule lumen). Therefore there is reduced water reabsoprtion in the cortical collecting duct and a larger volume of urine excreted. Problem: prohibitively expensive.
They exhibit aquaresis- the solute sparing excretion of renal water, as opposed to diauresis, which has simultaneous electrolyte loss.
Bromocriptine/ cabergoline- what are they? What do they treat? Two effects? How are they administered? Side effects?
D2 receptor agaonists. Treat hyperprolactinaemia. They reduce prolactin secretion and tumour size. Orally administered. Side effects include nausea and vomiting, depression, postural hypotension and dyskinesias.
Octreotide: what is it? What does it treat? When? How is it administered? Two effects? Side effects?
A somatostatin analogue. Treats acromegaly/gigantism. 2nd- after surgery (trans-sphenoidal). Adminstred subcutaneous. Reduce GH secretion and tumour size. Side effects include GI problems like nausea and gallstones.
