Adrenergic 2 Flashcards
NON-SELECTIVE alpha ADRENERGIC BLOCKERS?
- PHENOXYBENZAMINE
* PHENTOLAMINE
Uses of Phenoxybenzamine?
• Irreversible antagonist. • Unsuccessful for hypertension. • Used in Pheochromocytoma • Prior to surgical removal of the tumor. • For chronic management of inoperable tumors.
Uses of Phentolamine?
Reversibly blocks alpha 1 and alpha 2 receptors.
• Pheochromocytoma: control of hypertension
during preoperative preparation and surgical
excision.
• Diagnosis of pheochromocytoma: phentolamine
blocking test.
• Prevention of dermal necrosis after extravasation
of norepinephrine.
• Hypertensive crisis due to stimulant drug
overdose.
What are the alpha 2 selective adrenergic blockers?
PRAZOSIN
TERAZOSIN
DOXAZOSIN
TAMSULOSIN
What are the alpha 2 selective adrenergic blockers uses? CV effect?
treatment of Htn(Not DOC), prazosin is the prototype.
• Lower arterial blood pressure by relaxing both
arterial and venous smooth muscle.
• First dose produces an exaggerated
hypotensive response that can result in syncope
(fainting).
• The first dose must be 1/3 or 1/4 of normal
dose.
BPH
• DOC for symptom relief.
• Relax smooth muscle in the bladder neck,
prostate capsule and prostatic urethra improving
urinary flow.
Tamsulosin selective for which receptor? Uses?
• Three subtypes of the α1 -receptor: α1A , α1B , α1D . • The α1A -receptor predominates in GU smooth muscle. • Tamsulosin is selective for α1A -receptors. • Approved for BPH. • Little effect on blood pressure. • Less likely to cause orthostatic hypotension.
TERAZOSIN & DOXAZOSIN uses and pharmokinetic difference from prazosin?
- Prazosin analogs with longer half-life.
* Used for hypertension and BPH.
What are the Non selective Beta blockers?
PROPRANOLOL (The prototype)
NADOLOL
TIMOLOL
Effects: slow heart rate and decrease myocardial contractility
• Nonselective β blockers are contraindicated
in patients with asthma.
decreasd glycogenolysis and glucagon secretion
ATENOLOL & METOPROLOL uses?
Beta 1 selective adrenergic antagonists
• Useful in hypertensive patients with impaired
pulmonary function.
• Useful in diabetic hypertensive patients who are receiving insulin or oral hypoglycemic agents
Esmolol uses and pk, roa?
Beta 1 selective adrenergic antagonists
• Ultra-short acting
• Half life ̴10 minutes
• Given IV
• For rapid control of ventricular rate in patients
with atrial fibrillation or atrial flutter.
CARVEDILOL uses?
- Similar to labetalol.
- Has antioxidant properties.
- Used in hypertension and CHF.
LABETALOL uses and moa?
- Competitive antagonist at betaand alpha 1 receptors.
- More potent as a beta-antagonist than as an αantagonist.
- Used in hypertension.
Pindol use?
PARTIAL beta-AGONIST
• May be preferred in individuals with diminished
cardiac reserve or a propensity to bradycardia.
What are all of beta blocker uses?
Performance Anxiety (“Stage Fright”) • β-blockers are the preferred treatments.
MI
• beta-blockers have a protective effect on the
myocardium.
Atrial Fibrillation
• beta-blockers are indicated to control ventricular
rate.
Angina Pectoris
• beta -blockers decrease O2 requirement of heart
muscle.
• Useful in chronic management of stable angina.
• Not for acute management
.Hyperthyroidism
• beta-blockers blunt sympathetic stimulation that
occurs in hyperthyroidism.
Glaucoma
• beta-blockers, particularly timolol, are effective in
diminishing intraocular pressure in glaucoma.
Migraine
• beta-blockers are effective for prophylaxis of
migraine.
Hypertension
• beta-blockers lower blood pressure in hypertension
by decreasing cardiac output
Essential Tremor
• Essential tremor is the most common neurologic
cause of postural or action tremor.
• β- blockers are the most commonly used drugs
for the treatment of essential tremor.
Beta blocker AE
Bronchoconstriction
• Nonselective beta-blockers: Potentially lethal side
effect in asthmatics.
• beta1-selective drugs may be less likely to
evoke bronchospasm.
• The selectivity of beta blockers for beta1 receptors
is modest: they should be avoided if at all
possible in patients with asthma.
Hypoglycemia
• Nonselective beta-blockers may impair recovery
from hypoglycemia in insulin-dependent diabetics.
Due to blockade of beta2 receptors in the liver.
• Also, they mask the tachycardia typically seen
with hypoglycemia, denying the patient an
important warning sign.
• A beta1-selective blocker is preferable.
Lipid metabolism
• Blockade of beta receptors inhibits release of free
fatty acids from adipose tissue.
• Both non-selective and β1-selective blockers
increase TG and reduce HDL.
• Lipid levels are relatively unaffected by labetalol
and partial agonists like pindolol.
CNS effects: sedation, dizziness, lethargy, fatigue
Beta blocker warnings and precautions?
• β-blockers should not be withdrawn abruptly
(particularly in patients with CAD).
• They should be gradually tapered to avoid acute
tachycardia, hypertension, and/or ischemia.
• These adverse effects are due to up-regulation
of β-receptors.
alpha-METHYLTYROSINE (METYROSINE) uses?
INHIBITORS OF NOREPINEPHRINE SYNTHESIS
• Competitive inhibitor of tyrosine hydroxylase.
• Used for management of malignant
pheochromocytoma.
• Used in preoperative preparation of patients for
resection of pheochromocytoma.
Inhibitors of Norepinephrine storage?
RESERPINE
TETRABENAZINE
Uses of Resperine?
• Irreversibly blocks VMAT. Vesicles cannot store
norepinephrine and dopamine.
• This causes depletion of norepinephrine, since
MAO degrades norepinephrine in the cytoplasm.
• Gradual decrease in blood pressure and slowing
of cardiac rate.
• Used in the past to treat hypertension.
Uses of Tetrabenazine?
• Reversible inhibitor of VMAT.
• Causes presynaptic depletion of catecholamines.
• Indicated for the treatment of chorea associated
with Huntington’s Disease.
function and receptor of each tissue? Pupillary dilator (radial) muscle in the iris. Pupillary constrictor (sphincter) muscle in the iris. Ciliary muscle Ciliary epithelium
Pupillary dilator (radial) muscle in the iris.- contraction causes mydriasis, receptor- alpha 1
Pupillary constrictor (sphincter) muscle in the iris.- contraction causes miosis. Receptor- M3
Ciliary muscle- Contraction adapts to short range focus.
Relaxation adapts to long range focus. Receptor- M3
Ciliary muscle contraction facilitates outflow of aqueous humor in Canal of schlemm.
Ciliary Epithelium-produces aqueous humor. Receptor-Beta2
