Adrenoceptor anatagonists Flashcards
List some of the alpha adrenoceptor antagonists
- Prazosin (alpha 1 >>>> alpha 2)
- Phenoxy-benzamine (alpha 1> alpha 2)
- Phentolamine (alpha 1 = alpha 2)
- Yohimbine (alpha 2>alpha1)
describe the general effects of alpha receptor antagonists
- Decrease blood pressure, orthostatic hypotension
- Tachycardia
- reverse the pressor effects of alpha and Beta agonists
- miosis
- nasal stuffiness
- decrease resistance to urine flow
describe some general therapeutic uses for alpha receptor antagonists
- PHEOCHROMOCYTOMA
- hypertensive emregencies
- chronic hypertension
- peripheral ascular dsiease
- urinary obstruction
- erectile dysfunction
Phenoxybenzamine (dibenzyline)
ALPHA RECEPTOR ANTAGONISTS
- Irreversibly blocks alpha1 and alpha 2
- EFFECT = lowers blodd pressure but heart rate rises due to baroreflex activation
- USED TO TREAT PHEOCHROMOCYTOMA or high catecholamine states
PRAZOSIN (minipress)
ALPHA RECEPTOR ANTAGONISTS
- Alpha 1 selective, but not alpha 2
- EFFECTS: relaxes arterial, venous and prostate smoth muscle
–> LOWERS BLOOD PRESSURE
- USES: hypertension, benign prostatic hyperplasia
ADVERSE: can cause orthostatic hypotension (first dose)
TAMSULOSIN (flomax)
ALPHA RECEPTOR ANTAGONISTS
- slightly selective for ALPHA 1a
–> EFFECTS: relax prostatic smooth muscles
- USES: tx for benign prostatic hyperplasia
Yohimbine
ALPHA RECEPTOR ANTAGONIST
- Blocks alpha2 (increases central sympathetic activity and NE release)
–> RAISES BP and HR
- uses male erectile dysfunction and hypotension
- ADVERSE EFFECTS: anxiety
LABETALOL
- Beta Adrenoceptor antagonists (mixed alpha/beta antagonist)
- BLOCKS Beta > alpha 1
–> EFFECTS: LOWERS BP with limited HR increase
- USES: tx of HYPERTENSION
- Side effects = less tachycardia
describe the general cardiovasclar effects of BETA RECEPTOR ANTAGONIST
- decrease inotropic, chronotropic –> DECREASE BLOOD PRESSUE in pts with hypertension (NO EFFECT on NORMOTENSIVE patients)
- decrease myocardial oxygen consumption
- decrease renin release
describe the general respiratory effects of BETA RECEPTOR ANTAGONISTS
- Beta 2 blockade –> increase airway resistance
- UNDESIRABLE IN ASTHMA/COPD
- No Beta blocker is completely free of BETA2-blocking effect
describe the general effects of BETA RECEPTOR ANTAGONISTS on the eye and metabolism
-EYE:
–> decrease aqueous humor production –> DECREASE INTRAOCULAR PRESSURE
- METABOLIC
–> inhibits lipolysis
–> may decrease glucagon release
–> increase VLDL and decrease HDL
describe the uses of beta receptor antagonists
- hypertension
- ischemic heart disease
- cardiac arrhythmias
- heart failure
- glaucoma
- hyperthyroidism
- neurologic diseases
describe the adverse effects of BETA RECEPTOR ANTAGONISTS
- fatigue
- worsening peripheral vascular disease
- worsening bronchospasm
- decreased sexual functions
- increased incidence of diabetes
- masking the symptoms of hypoglycemia (blocks all of the normal symptoms of hypoglycemia EXCEPT FOR SWEATING)
List the nonselective Beta receptor antagonists
- Beta 1 = beta 2
- PROPRANOLOL
- nadolol
timolol
pindolol (has intrinsic sympathaminmetic activity (ISA)
describe the SELECTIVE Beta receptor antagonists
- BETA 1 >>>> BETA 2
- atenolol
- METOPROLOL
- ESMOLOL
- BETAXOLOL
- ACEBUTOLOL - has ISA
(AMEBA)
describe the vasodilatory Beta receptor antagonists
- B1 = B2 > Alpha 2 > alpha 2
- LABETALOL
PROPRANOLOL
Beta adrenergic receptor antagonists
- Block beta 1 and Beta 2
- EFFECTS: lower HR and BP; REDUCE RENIN
- USES: Hypertension, angina pectoris, arrhythmias, migraine
METOPROLOL
Beta adrenergic receptor antagonists
- Blocks Beta 1 > Beta 2
- Effects: lower HR and BP; reduce renin
–> safer in asthma
- USES: angina pectoris, hypertension, arrhythmias
Pindolol and acebutolol
- Beta adrenoceptor antagonists
- Beta 1 and beta 2 WITH ISA
- EFFECTS: lowers BP modestly; lowers HR
- USES: hypertension, arrhythmias, migraine
Carvedilol (labetalol)
Beta-adrenoceptor antagonists
- BLOCKS Beta > alpha 1
- EFFECTS: long half-life; lowers BP with limited HR increase
- USES: Heart failure/ hypertension
What are the properties important for choice of Beta blockers
- Cardioselectivity
–> people with COPD or asthma (lose dose of selective)
- Intrinsic sympathomimetic activity
–> Used when you don’t want to drop the HR but want to reduce blood pressure
- lipid solubility]
–> If compound is lipid soluble then the plasma conc will be LESS PREDICTABLE.
–> older people may have kidney/liver disease and unable to metabolize the beta blockers as well.
