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73 Cards in this Set
- Front
- Back
What is the order of affinity of EPI, NE, and ISO on alpha receptors?
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EPI > NE >> ISO
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What is the order of affinity of EPI, NE, and ISO on beta-1 receptors?
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ISO > EPI = NE
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What is the order of affinity of EPI, NE, and ISO on beta-2 receptors?
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ISO > EPI >> NE
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What are the cardiovascular effects of Isoproterenol?
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Heart:
↑ Rate ↑ Contractility Vascular Smooth Muscle: ↓ Peripheral Resistance ? Blood Pressure |
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What are the cardiovascular effects of Norepinephrine?
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Heart:
↑ Rate (but then goes down b/c of vagal reflex) ↑ Contractility (but then goes down b/c of vagal reflex) Vascular Smooth Muscle: ↑↑ Peripheral Resistance ↑↑ Blood Pressure |
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What is the reflex cardiovascular effect of NE?
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↓ Heart Rate
↓ Contractility Secondary to increase in BP -> strong vagal compensation overcomes direct effects on heart |
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What are the cardiovascular effects of EPI?
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Heart:
↑ Contractility ↑ Heart Rate Vascular Smooth Muscle: ↓ Peripheral Resistance ↑ BP (mean) |
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Indirect-acting phenylethylamines lack what group?
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β-OH
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Which stereoisomer of phenylethylamines is the active form?
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L (or S)
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What alteration to phenylethylamines greatly increases their oral effectiveness and duration of action?
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Removal of one or both ring hydroxyls
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What alteration to phenylethylamines allows them to cross the blood-brain barrier?
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Removal of both ring hydroxyls
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What alteration to phenylethylamines enhances their resistance to MAO?
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Presence of an α-carbon substituent
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What are the contraindications or reasons for caution in sympathomimetic therapy? (8)
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1. Cardiac disease
2. HTN 3. Cerebral arteriosclerosis 4. DM 5. Hyperthyroidism 6. During general anesthesia with halothane or cyclopropane 7. Pregnancy 8. Pts receiving therapy w/ beta-receptor antagonists |
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Where in the cell is Acetyl CoA synthesized?
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Mitochondria
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Where do cholinergic cells store ACh?
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In vesicles
In the cytoplasm |
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Where do AChE inhibitors act on the AChE molecule?
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At the esteratic site
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Where in the body are muscarinic receptors located?
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Autonomic effector cells
Certain autonomic ganglion cells CNS |
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Which receptor, muscarinic or nicotinic, has faster response time?
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Nicotinic
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What type of receptors are muscarinic receptors?
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G-protein-linked
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Activation of M₁, M₃, and M₅ muscarinic receptors exerts what effect on cells?
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↑ IP₃ and DAG to ↑ Ca⁺⁺ and Na⁺
Causes increase in contraction and secretion |
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Activation of M₂ and M₄ muscarinic receptors exerts what effect on cells?
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Inhibition of cAMP formation
Increased K⁺ conductance Decreased Ca⁺⁺ conductance |
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Where in the body are nicotinic receptors located?
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Autonmoic ganglia
Skeletal muscle (NMJ) CNS |
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What type of receptor are nicotinic receptors?
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Ligand-gated ion channels
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Cholinomimetics are routinely used in the management of what four things?
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1. Gastrointestinal atony
2. Nonobstructive urinary bladder atony 3. Opthalmic disorders (glaucoma) 4. Myasthenia gravis |
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What are the most common side effects associated with usual therapeautic doses of cholinergic agonists?
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Salivation
Lacrimation Urination Defecation Sweating (SLUDS) |
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Which direct acting cholinomimetic is characterized by its short duration of action and what is it commonly used for?
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Methacholine
Used diagnostically to test for bronchial hyperactivity and asthmatic conditions |
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Which direct acting cholinomimetic is used to increase tone and contraction of the intestine and urinary bladder?
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Bethanechol
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Which direct acting cholinomimetics are regarded as being selective for muscarinic receptors?
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Methacholine
Bethanechol |
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Which non-selective direct acting cholinomimetic agent is used in the treatment of glaucoma?
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Carbachol
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Why is pilocarpine not a substrate for cholinesterases?
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It is not a choline ester
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What are four contraindications to the use of cholinomimetics?
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1. Asthma
2. Peptic ulcer 3. Coronary insufficiency 4. Hyperthyroidism (causes a-fib) |
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What are the three groups of cholinesterase inhibitors?
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1. Quaternary alcohols
2. Carbamate esters 3. Organophosphates |
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Which group of cholinesterase inhibitors is considered irreversible?
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Organophosphates
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What are three reversible cholinesterase-inhibiting drugs?
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Edrophonium
Neostigmine Physostigmine |
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What group of cholinesterase inhibitors does edrophonium belong to and what is its use?
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Quaternary alcohol
Diagnosis of myasthenia gravis (reversal of muscles weakness is indicative of condition) |
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What are the two significant characteristics of neostigmine?
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Longer acting
Stays out of the CNS (quaternary amine) |
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What are the major therapeutic uses for neostigmine?
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Nonobtrusive intestinal atony
Nonobtrusive urinary bladder atony Management of myasthenia gravis |
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Which reversible cholinesterase inhibitor is sometimes used in the treatment of glaucoma?
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Physostigmine
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How long does "aging" of AChE bound to organophosphates take?
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About 1 hour
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What is the only clinical use of organophosphates and which drugs are used?
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Glaucoma (as a last resort)
DFP and echothiophate |
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Does atropine penetrate the CNS?
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Only in large doses
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Which subtypes of muscarinic receptors does atropine block?
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All of them
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What is the classic non-muscarinic effect of atropine?
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Dilation of blood vessels in facial blush area
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Cholinergic blockers are commonly used in the routine management of patients with what? (5)
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1. Gastric hypermobility and sapsticity
2. Escessive salivation 3. Need for mydriatic and cyclopegic 4. Cystitis, ureteral or biliary colic 5. Parkinson's Disease |
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What are the three groups of cholinergic blockers?
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Muscarinc blocking drugs
Ganglionic blockers Nuromuscular blockers |
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Name three muscarinic blockers.
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Atropine
Scopolamine Ipratropium |
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What effect does atropine have on NMJs?
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None - it is selective for muscarinic receptors
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Which pts should not receive topical application of atropine to the eye?
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Pts with narrow-angle glaucoma
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What is the key difference between scopolamine and atropine?
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Scopolamine exerts more CNS action (drowsiness and amnesia)
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What is ipratropium used for?
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Administered by inhalation in reversible airway disease
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What are the therapeutic uses of muscarinic blockers? (6)
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1. Before anesthesia
2. To combat motion sickness 3. To manage Parkinson's disease 4. To treat intestinal spasms 5. To prepare the eye for examiniation; to treat iritis 6. To treat poisoning and certain bronchial conditions |
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What are nondepolarizing ganglionic blockers used for?
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Short-term control of blood pressure in HTN crises
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What are depolarizing ganglionic blockers used for?
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NOTHING!!!!
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What is the nondepolarizing ganglionic blocker we need to know?
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Trimethaphan camsylate
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How is trimethaphan administered and why?
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Continuous IV b/c of rapid metabolization by plasma ChE
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What is an important side effect of trimethaphan?
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Histamine release
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Curare, atracurium, cecuronium and mivacurium are in what class of drugs?
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Nondepolarizing NMJ Blockers
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Compared to curare, atracurium ...
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Has shorter duration of action
Has some histamine release |
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Compared to curare, vecuronium ...
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Has shorter duration of action
Does not cause histamine release Does not cause ganglionic blockade |
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Compared to curare, mivacurium ...
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Has less histamine release
Is very short acting |
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What is the order in which curare paralyzes skeletal muscles?
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Eye muscles
Jaw muscles Muscles controlling swallowing Peripheral muscles Abdominal and intracostal muscles Diaphragm |
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Potential complications of curare are what?
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Hypotension
Bronchoconstriction |
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What drugs antagonize curare?
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Neostigmine
Edrophonium |
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What type of drug is succinylcholine?
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Depolarizing NMJ Blocker
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How long does skeletal muscle paralysis persist following IV injection of succinylcholine?
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5 minutes
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How is succinylcholine metabolized?
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By plasma pseudo-ChE
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What are therapeutic uses of β1 adrenergic receptor antagonists? (11)
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1. Ventricular and supraventricular arrhythmias
2. Angina pectoris 3. HTN 4. Cardiac myopathies 5. Long-term prophylaxis after MI 6. Prophylaxis of migraine 7. Hyperthyroidism 8. Glaucoma 9. Management of pheochromocytoma 10. Acute freight/stress syndromes 11. Skeletal muscle tremors |
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What are therapeutic uses of α-adrenergic receptor antagonists? (8)
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1. Essential HTN
2. HTN crises 3. Vasopastic conditions 4. Frostbite 5. Therapeutic management of pheochromocytoma 6. Circulatory shock 7. Congestive heart failure 8. Urinary obstruction (BPH) |
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What effect does propanolol have on blood pressure?
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Initially it raises it, but given chronically it will lower it, especially in pts w/ HTN
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Which has a longer half life, metoprolol or atenolol?
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Atenolol
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Which β1 selective blocker has a very short duration of action?
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Esmolol
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What is the clnical use of labetalol?
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It is a potent antihypertensive
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What undesireable effect of non-selective α receptor antagonists severly limits their clinical use?
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Tachycardia
(also cause postural hypotension) |