Adrenergic Antagonists Flashcards
Important side effect to remember with alpha adrenergic antagonists
Sexual Dysfunction
Three examples of alpha1 adrenergic antagonists
Prazosin
Terazosin
Doxazosin
Clinical use of alpha1 adrenergic antagonists
Hypertension, Benign Prostatic Hypertrophy
Side effects of alpha1 adrenergic antagonists
Orthostatic Hypertension
Inhibition of Ejaculation
Nasal stuffiness
Tachycardia
Important thing to remember about phenoxybenzamine
Nonselective (Dirty Drug)
Irreversible antagonist resulting from covalent modification of receptor
Chemical details about phentolamine
Non-selective alpha receptor agonist
Competitive
Effects of phentolamine use
Potent vasodilator, but gives pronounced tachycardia
blocks presynaptic alpha2 and 5HT
Important difference between Prazosin, Terazosin, and Doxazosin
Halflife.
P3
T12
D20
Effects of Prazosin, Terazosin, and Doxazosin?
Vasodilators
Relaxation of smooth muscle in enlarged prostate and bladder base
What is the first dose effect?
In drugs like Prazosin, Terazosin, and Doxazosin, first dose may lead to orthostatic hypotension
What is Yohimbine?
Indole alkaloid
Blocks alpha2 receptors, increasing sympathetic discharge
beta blockers were one of the first major _______ drugs
Rationally Designed
Who is the original G of beta blockers
Propranolol
Important chemical attributes of beta blockers
Non-selective
Lipophillic - CNS access
Local anesthetic properties
Blockade is activity-dependent
Pharmacological effects of Propranolol
Lowers CO and heart rate
Reduced Renin Release
Increased VLDL, HDL (inhibited lipolysis)
Inhib. compensatory glycogenolysis and GLU release
Increases bronchial airway resistance
Main way beta blockers inhibit HTN?
Reduced Renin Release
Therapeutic uses for beta-blockers?
HTN, angina, arrythmia,
migraine, stage fright,
thyrotoxicosis, glaucoma,
CHFII-III
What should you know about Nadolol
Less lipophilic than propranolol
Long Half life (20h)
Used for HTN, angina, migraine
What should you know about Timolol
Thiadiazole nucleus with morpholine ring
HTN, angina, migraine, GLAUCOMA
How do beta blockers affect pupil size?
They don’t
They’ll decrease pressure without effects like cholinergic
What is unique about Pindolol?
Possesses Intrinsic sympathomimetic Activity (Partial Agonist)
Less likely to cause bradycardia and lipid abnormalities
HTN, Angina, Migraine
Other than Pindolol, whats the other important partial agonist? Why care?
Carteolol
Less likely to cause bradycardia and lipid abnormalities
Used for HTN and glaucoma
Three selective beta1 adrenergic receptor antagonists
Metoprolol, Bisoprolol, Atenolol, Esmolol
Metoprolol and Bisoprolol – what does it do?
Cardioselective, doesn’t trigger the bronchoconstriction
Metoprolol and Bisoprolol half life
3-4 hours
Metoprolol and Bisoprolol uses?
HTN, angina, anti-arrhythmic, CHF
What’s the deal with atenolol?
Cardioselective, low lipophilicity, 6-9 hour halflife
Treats HTN and angina
What characteristic of Esmolol different from the other beta1 adrenergic receptor antagonists?
Very short half life (ex. 9 minutes) caused by rapid hydrolysis by esterases found in RBCs
What is Esmolol used to treat?
Supraventricular tachycardia
Atrial fibrillation/Fluter
Perioperative HTN
Who did he say was a 3rd gen beta blocker
Nebivolol (Bystolic)
Important details for nebivolol
Beta1 selective, but also causes vasodilation by NO production
Used to treat HTN
Two examples of mixed adrenergic receptor antagonists
Labetalol
Carvedilol
Chemical mechanism of Labetalol
Non-selective beta receptor antagonist + alpha1 receptor antagonist
What is Labetalol used for?
beta-blocking activity prevents reflex tachycardia normally associated with alpha 1 receptor antagonists
HTN, Hypertensive Crisis
Chemical data for Carvedilol?
Non-selective beta antagonist, alpha1 receptor antagonist
How does Carvedilol work?
Beta blocking activity prevents reflex tachycardia normally associated with alpha1 receptor antagonists
Uses for Carvedilol?
HTN, CHF
Side effects associated with beta-blockers
Bradycardia, AV block, sedation, mask symptoms of hypoglycemia, withdrawl
Contraindications for beta blockers?
Asthma, COPD, CHF-Type 4
Example given for a catecholamine depleter
Reserpine
Molecular activity of Reserpine
Block vesicular monoamine transporters
Depletes the vesicular pool of NE
Reserpine is used to treat…
HTN
Important side effect of Reserpine
Depression
