Adrenergic antagonists Flashcards
Phenoxybenzamine
Nonselective alpha antagonist
Irreversible - non-competitive
Alpha1 > alpha2
Blocks several other receptors, cross BBB
Blockade ends after new receptor synthesis
Vasodilation and reflex tachycardia (block a1 but increase NE via a2)
Nausea, vomiting and weakness
Use of phenoxybenzamine
Pheochromocytoma
Peripheral vascular disease
Raynaud’s syndrome
Acrocyanosis
Phentolamine
Like Tolazoline
Competitive alpha blocker Rapid onset Decrease BP Enhance NE release Stimulate GI and HCl/Pepsin release
Phentolamine use
Pheochromocytoma
Clonidine withdrawal
Treat necrosis
SE: orthostatic hypotension
Yohimbine
Alpha 2 and 5HT blocker
Improve male sexual function?
Chlorpromazine, haloperidol
Block alpha1 and DA
Antipsychotic
Ergotamine
Treat migraine HA
Ergonovine
Treat postpartum hemorrhage
Prazosin
Alpha 1 selective antagonist
Treat HTN without reflex tachycardia
Considerable syncope in patients
Terazosin
HTN and BPH
Alpha 1 antagonist
Doxazosin
HTN and BPH
Alpha 1 antagonist
Tamulosin
Alpha1A subtype
BPH with little orthostatic hypotension
Propranolol
Competitive beta blocker
Decrease HR, decrease exercise tolerance, decrease infarct
Slowly decreases peripheral resistance
**Caution with asthmatics and diabetics
May penetrate CNS - drowsiness
Propranolol metabolism
Largely reduced by first pass
Use of Beta blockers
Angina Very helpful with CHF HTN HA Arrhythmias Pheochromocytoma Hyperthryoid Anxiety MI, post MI
Beta blocker sudden withdrawal
Angina, HTN, possible MI
Beta blocker drug interactions
Hypotensive agents
Insulin (mask hypoglycemia)
Nadolol
Longer lasting beta blocker
Timolol
More potent beta blocker
HTN and glaucoma
Metoprolol
Cardioselective beta blocker
Atenolol
Cardioselective beta blocker
Labetalol
Alpha 1 and beta receptors blocker
HTN and pheochromocytoma
Carvedilol
Alpha 1 and beta blocker
**very helpful with CHF
Pindolol
like carteolol
Reduces sympathetic tone on heart (compete with Epi and NE)
HTN
Acebutolol
Cardioselective for beta1 blocker
HTN, dysrhythmias
Betaxolol
Beta1 selective blocker
Glaucoma and HTN
Bisoprolol
CHF
Esmolol
Rapid onset and short acting selective beta1 blocker
Use around surgery
Still use cautiously with asthmatics
Guanethidine
Uptake I - Displacement and release of NE - Blocks NE release
Does not enter CNS
Uncontrolled HTN
Guanadrel
Like Guanethidine but more rapid and shorter duration
Bretylium
Blocks NE
Antiarrhythmia
Clonidine
Alpha 2 agonist
Can enter CNS and downregulate sympathetic
Initial increase in BP then decrease in BP
Treat opioid withdrawal
Sudden clonidine withdrawal
HTN crises
Methyldopoa
HTN in pregnant females
Guanabenz
Like Clonidine but less useful
