Adrenergic antagonists Flashcards
Adrenergic antagonists
- a-blocking agents
- b-blocking agents
- drugs affecting NT uptake / release
a-blocking agents -> all reverse the a-agonist action of E
- doxazosin (a1)
- phenoxybenzamine (non-selective)
- phentolamine (non-selective)
- prazosin (a1)
- terazosin (a1)
b-blocking agents -> HT
- acebutolol (b1)
- atenolol (b1)
- labetalol (a and b)
- nadolol (non-selective)
- pindolol (non-selective)
- propanolol (non-selective)
- timolol (non-selective)
Drugs affecting NT uptake / release
- cocaine (stimulates a1 and b)
- guanethidine (blocks NE release)
- reserpine
Phenoxybenzamine
R:
- non-selective
- links covalently to both a1 and a2 presynaptically
PK: block is irreversible and non-competitive
TU:
- treatment of pheochromocytoma
- decrease PR -> reflex tachycardia and ability to block a2 -> increase CO (unsuccessful in maintaining lower BP)
AE:
- postural hypotension
- nasal stuffiness
- nausea, vomitting
- inhibits ejaculation
- reflex tachycardia
CI: in pts w/ low coronary perfusion
Phentolamine
R: non-selective (a1 and a2)
PK: competitive block
TU: diagnosis of pheochromocytoma and other situations related to CA excess release
AE:
- postural hypotension
- E reversal
Prazosin
Terazosin
Doxazosin
R: selective a1
PK: competitive block
TU:
- treatment of HT -> vasodilation
- alternative to surgery in treatment of benign prostatic hypertrophy
AE:
- first dose effect
- sexual function in males isn’t severily affected as w/ phentolamine
Propanolol
R: non-selective
TU:
- negative inotropic and chronotropic effects
- decrease BP (HT treatment)
- glaucoma, migraine, MI, angina pectoris, hyperthyroidism
AE:
- bronchoconstriction
- arrhythmias
- sexual impairement
- decrease glycogenolysis
- decrease glucagon secretion
Timolol, Nadolol
R: non-selective
TU:
- open angle glaucoma
- systemic HT (occasionally)
Acebutol
Atenolol
Metoprolol
Esmolol
R: selective b1
TU: HT, diabetic hypertensive pts
Pindolol (non-selective)
Acebutol (selective b1)
PK:
- not pure blockers
- ISA
TU: effective in HT pts w/ bradycardia
Labetalol
R: a and b blocker
TU:
- elderly and black HT pts
- treat of PIH (pregnancy induced HT)
Cocaine
Blocks cellular reuptake of NE (inhibits Na/K ATPase).
Stimulates a1 and b effects
TU:
- increase BP (stimulate a1 and b effect)
- small doses of CA produce greatly magnified effects in an individual taking cocaine, as compared to those who aren’t -> interactions w/ E
Guanethidine
Blockes release of stored NE.
TU: rarely used in HT
AE: HT crisis in pts w/ pheochromocytoma
Reserpine
Alkaloid
Blocks Mg/ATP dependent transport of biogenic amines, NE, dopamine, serotonin, from the cytoplasm into storage vesicles in the adrenergic nerves of all body tissue
TU: HT pts show gradual decrease in BP
Imipramine
Mechanism = cocaine
Inhibits uptake of NE by inhibiting Na/K activated ATPase
Quanethidine and Bretylium
Inhibit uptake of NE Block release (specific for CA)
