Lecture 5 Flashcards
WHat effect will an antagonist have on a receptor activation
No effect
a-adrenergic receptor antagonists (non-selective) drug names
Phenoxybenzamine and phentolamine
A1 selective drugs
prazosin, terazosin, doxazosin (ENDS WITH SIN)
A1 selective drugs ROA
Oral
A1 selective clinical use
HTN, BPH,
A non-selective clinical uses
Pheocromocytoma, hypertensive crisis
Side effects of A1 antagonists
Hypotension, inhibition of ejaculation, tachycardia
how does phenoxybenzamine form a covalent bond
Covalent bond forms at CL. It becomes irreversible
Why is phenoxybenzamine irreversible?
Haloalkene forms covalent bond
reversible non-selective a-adrenergic receptors antagonist name
phentolamine
Why are non-selective a-adrenergic blockers not used
A-2 blocking promotes release of NE
Why does phenoxybenzamine lead to long drug effects
It is a non-competitive irreversible drug. New receptors must be synthesized to restore receptor function.
Why non-selective a- adrenergic receptors not used for HTN?
A2 blockage will lead to increase of NE at heart and increased heart rate
a1 selective general structural feature.
Quinazoline ring
selective a1 antagonist clinical use
Hypertension, Reynauds disease, BPH
A1a antagonist name and use
Tamsulosin. Used for BPH. (A1a found in prostate urethra)
Why is tamsulosin less likely to lead to fall in BP?
Tamsulosin is very selective to A1a
B adrenergic antagonist structural feature
O/\OH/\NHR(3 carbons between NHR and O, with an aromatic on O)
All B blockers end with
Olol
Which side of the B blocker determines lipophilicity
Aromatic ring
Lipophilic B blockers tend to be on which organs
Liver
Lipophilic drugs tend to have
A. Strong 1st pass metabolism
B. weak 1st pass metabolism
A
Non-selective B blocker name
Propanolol
B antagonist pharmacologic effect
Decreased cardiac output
Decreased renin release
Increased bronchial airway resistance
Increased VLDL and decreased HDL
