Pharm REVERSE -adnrenergic antagonists Flashcards
drugs that disrupt the synthesis, storage or release of norepinephrine
What is the mechanism of adrenergic neuron blockers?
1) Guanethidine
2) Guanadrel
3) Reserpine
Which drugs are Adrenergic neuron blockers? (3)
Inhibits norepinephrine release and depletes neuronal amine stores
What is the mechanism of Guanethidine and Guanadrel? (2)
Severe hypertension
What is the therapeutic use of Guanethidine and Guanadrel?
Guanethidine is a polar compound that does not enter the CNS
What is the difference between Guanethidine and Guanadrel?
NET - therfore they are inhibited by tricyclic antidepressants that inhibit NET
How are Guanethidine and Guanadrel taken up into the cell?
Many side effects: orthostatic hypotension, interferes with sexual function, diarrhae, muscle weakness, edema
What are the side effects of Guanethidine and Guanadrel?
It inhibits he vesicular monamine oxidase transporter 2 (VMAT2) therby inhibiting the synthesis of norepinephrine
What is the mechanism of Reserpine?
diffusion (does not need VMAT2)
How does Reserpine get into the cell?
treats essential hypertension - rarely used
What is the therapeutic use of Reserpine?
Many CNS side effects, depression, suicide, sedation
Other side effects: diarrhae, orthostaic hypo-tension, increased gastric acid secretion
What are the side effects of Reserpine?
Slow onset and Long acting
What is Reserpine’s length of onset and how long does it last?
Agents produce their major actions by inhibiting alpha and beta receptors. Both exogenously administered as well as endogenously released catecholamines are blocked
What is the mechanism of adrenergic receptor blockers?
1) Phenoxybenzamine
2) Phentolamine
3) Prazosin
4) Tamsulosin
What drugs are alpha adrenergic receptor antoganists? (4)
irreversible inhibition of a1 and a2
Phenoxybenzamine
Irreversible antagonist via covalent bonding with receptor. New receptors need to be synthesized, so it is very long lasting
What is the mechanism of Phenoxybenzamine?