Adrenergic Antagonists Flashcards
What are 2 non-selective a blockers?
Phentolamime and Phenoxybenzamine
Phentolamine
Competitive a-blocker (reversible)
Used in hypertension (cocaine induced)
Phentolamine a1 block
Within 2 minutes: peripheral vasodilation and decreased BP, elicit baroreceptor-mediated cardiac stimulation reflex
Phentolamine a2 block
Enhanced neural release of NE
Phenoxybenzamine
Non competitive (irreversible)
1-2 days to synthesize new receptors
a1>a2 blockage
Used for malignant hypertension snd pheochromocytoma
Selective a1 blockers
Prazosin
Terazosin
Tamsulosin
Prazosin
Most potent and highly selective
Used in systemic hypertension in dogs, benign prostatic hyperplasia
Doesn’t oriudce reflex tachycardia (no a2 blockade)
Terazosin
Long-acting
Humans for reaction of benign prostatic hyperplasia
Tamsulosin
Selective for a1A receptors (prostate) and a1B in BVs
Used in benign prostatic hyperplasia
_______________ used to decrease intraocular pressure in glaucoma
Bunazosin
Selective a2 blockers
Yohimbine and atipamezole
Yohimbine
Alkaloid from plants
Blocks a2 receptors at lower concentration
Reverse effects of xylazine and dexmedetomidine overdose
Antipode to amitraz poisoning
Atipamezole
Synthetic
Reversal drug for medetomidime and dexmedetomidine induced adverse effects
Non-selective b adrenergic antagonists (first generation)
Propranolol
Pindolol
Nadolol
Sotalol
Timolol
Propranolol
Interacts equally with b1 and b2 receptors by decreasing HR and bronchospasms
Migraines and decreases aqueous humor production (open angle glaucoma)
Nonselective B blockers are not recommended in patients with ________
Asthma or COPD
Another name for b1 selective blockers (second generation)
Cardio-selective b-blockers
b1 selective blockers (second generation)
Atenolol
Betaxolol
Esmolol
Acebutalol
Metoprolol
Uses of B blockers
Hypertension
Angina pectoris
Cardiac arrhythmias
Myocardial infarction
Glaucoma
Migraine
3rd generation b blockers
Act on BVs to cause vasodilation and treatment if hypertension
Non-selective: carvedilol and ladetalol
Selective: nebivolol and betaxolol
Nebivolol
B1 selective
Induces nitric oxide release from endothelial cells causing vasodilation
Betaxolol
Blocks calcium channels
Reduces intraocular pressure when applied
Used for glaucoma treatment
Carvedilol and nebivolol also has _________ properties
Antioxidant
What drugs prevent NE release?
Guanethidine and Bretylium
(Only interfere at neuron level not organ)
Which drug is the first to interfere with synthesis?
Methyl-p-tyrosine (metyrosine) will inhibit the enzyme try’s one hydroxylase requireD to form DOPA
Reserpine
In horses used as a long-acting tranquilizer (sedation)
Inhibits uptake of NE into storage vesicles
Antihyoertensive and antipsychotic
__________ is the response to reserpine
Methamphetamine
Which drugs inhibit the release of NT?
Guanethidine and betanidone
Inhibit noradrenaline transport to nerve terminal by occupying carrier protein that takes it from vesicles to nerve terminal
Bretylium
Neuron nerve blocking agent used in humans as a anti hypertensive drug
