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79 Cards in this Set
- Front
- Back
Which type of chronic pain is characterized by a poor correlation between tissue pathology and pain?
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Chronic Non-Cancer Pain
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What type of pain is usually cutaneous or superficial?
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Somatic
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What type of pain is deep, dull, and poorly localized?
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Visceral
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What is the quality of neuropathic pain?
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Burning or dysesthetic
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Neuropathic pain results from damage to what?
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A peripheral nerve
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Where do fast and slow pain fibers synapse?
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On second-order neurons in the dorsal horn of the spinal cord
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Where do 2nd order pain neurons in the spinal cord project?
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Medulla and/or thalamus
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What is the basic mechanism of local anesthetics?
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Blockade of voltage-gated Na⁺ channels
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What are the two important features common to both amide and ester forms of local anesthetics?
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1. Hyprophilic amine and hypdrophobic aromatic moiety
2. The amine can be protonated, with pKa of 7.5-9.0 |
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Which form of a local anesthetic, the charged or uncharged, is more membrane-permeable?
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The uncharged
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Which form of a local anesthetic, the charged or uncharged, is a better blocker?
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The charged
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What is the function and significance, in terms of local anesthetics, of the selectivity filter on a voltage-gated Na⁺ channel?
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It allows entry of only Na⁺, H₂O, and H⁺ into the channel
The anesthetic molecules must diffuse through the cell membrane and reach their binding sites from inside the cell |
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True of False: Only the charged forms of local anesthetics can bind their receptor sites inside the Na⁺ channel.
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False
(charged binds better than free base, but free base can still bind) |
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Which pain fibers are blocked at lower concentrations of local anesthetics?
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Small, unmyelinated (C fibers)
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Which type of nerve fibers (touch, pain, temperature, motor, proprioception, etc) are blocked at the highest concentrations (i.e. last)?
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Touch, motor, proprioception (Aδ)
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What effect does inflamed tissue have on the local anesthetics?
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• Inflamed tissue has lower extracellular pH
• More drug is protonated (extracellular), so membrane diffusion is inhibited • Block of inflamed tissue is slower than normal |
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How are local anesthetics generally marketed/formulated?
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As hydrochloride salts
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Why does injection of local anesthetic hydrochloride solutions "sting"?
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Because of the acidity of the solutions
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How much unchanged local anesthetic is found in urine?
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Very little, if any
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How are ester LAs and amide LAs metabolized?
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Ester LAs = hydrolysis by plasma ChE
Amide LAs = hydrolysis by liver microsomal esterase |
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Which type of local anesthetics is rapidly degraded in blood by plasma cholinesterases?
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Ester LAs
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What are the cardiovascular effects of cocaine?
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Blocks NE uptake (vasoconstriction and HTN)
Increased HR |
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What is the relationship between blood solubility and induction rate for general inhaled anesthetics?
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Inverse
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Which inhaled anesthetic will have a faster rise in arterial tension, one with a low blood/gas partition coefficient (B/G) or one with a high B/G?
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Low (poorly soluble)
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What effect can mechanical hyperventilation have on in inhaled anesthetics?
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It can increase the rate of anesthesia onset
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Does pulmonary blood flow rate have a direct or inverse relationship with induction rate?
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Inverse
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What effect will heart failure have on the administration of inhaled anesthetics?
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It will increase the rate of induction
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What drug should be administered with extreme caution with halothane only (is OK with other inhaled anesthetics) and why?
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Epinephrine
Halothane uniquely sensitizes myocardium to dysrhythmias induced by catecholamines |
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What is the major route of elimination for inhaled anesthetics?
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Exhalation
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For which inhaled anesthetic is liver metabolism a significant process and important consideration due to the risk of severe hepatitis post-anesthesia?
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Halothane
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For which inhaled anesthetic is liver and renal metabolism a significant process and important consideration due to the risk of nephrotoxicity?
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Methoxyflurane
(metabolism releases fluoride ions) |
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What type of toxicity is a unique risk of N₂O and why?
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Hematotoxicity
N₂O oxidizes B12 |
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Which inhaled anesthetic can cause malignant hyperthermia and what is the treatment should this develop?
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Halothane
Dantrolene |
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Why can N₂O not be used alone as an inhaled anesthetic?
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100% N₂O ≠ 1.0 MAC
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What three barbiturates are often coadministered with inhaled anesthetics and what is their benefit?
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Thiopental
Methohexital Thiamylal Ultra-short acting - unconsciousness in ~30 seconds |
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What is the advantage of propofol over barbiturates?
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Recovery is even faster
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What is a risk with propofol that limits its use in some situations?
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Marked drop in systemic blood pressure
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What drug can be administered with inhaled anesthetics instead of propofol in patients with cardivascular disease?
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Etomidate
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What drug is valued in general anesthesia because it causes anterograde amnesia?
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Benzodiazepines (Midaxolam)
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What two factors limit the use of ketamine?
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1. Cardiovascular stimulant actions (but helps with pts in cardiovascular shock)
2. Postoperative psychomimetic reactions (give with a benzodiazepine) |
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What is the state induced by ketamine?
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Dissociative amnesia
(sedation, analgesia, amnesia, disconnection from surroundings) |
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What is the mechanism of action of ketamine?
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NMDA blockade
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What are the primary analgesics used during anesthesia?
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Opioids
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Which opioid carries an FDA block box warning and for what?
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Droperidol
Prolongation of QTc interval, leading to cardiac arrhythmias |
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What is the general (not molecular) mechanism of inhaled anesthetics?
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Disruption of normal neuronal function by increased inhibitory and decreased excitatory synaptic transmission
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What is the gold-standard treatment for Parkinson's disease?
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Levodopa
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Why does levodopa lose its efficacy over time?
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Because of continued neurodegeneration (loss of synapses)
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Why do other drugs still work once levodopa is no longer beneficial in treating a patient with Parkinson's Disease?
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Because the dopamine receptors are still present and can be activated directly
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What symptom is the result of an excess of levodopa?
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Dyskinesia
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Are anti-muscarinics useful in the treatment of Parkinson's disease?
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No
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What is entacapone?
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COMT inhibitor
(used with levodopa in treatment of PD) |
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What is carbidopa?
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Decarboxylase inhibitor
(used with levodopa in treatment of PD) |
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Selective dopamine agonists used in the treatment of Parkinson's Disease target which dopamine receptors?
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D₂-like Dopamine Receptors
(D₂, D₃, and D₄) |
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In most cases, antiphsychotic selections are made based on what?
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Side effect profile
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Dystonic reaction responds rapidly to what treatment?
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Anticholinergic drugs (IM or IV)
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What drugs work to treat APD-induced parkinsonism?
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Antimuscarinics
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Akathisia resulting from APDs can be treated how?
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Change of dose, drug, anti-EPS drugs
Propanolol Lorazepam |
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What is the nature of the relationship between the log dose and log affinity of the typical antipsychotics?
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Linear
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What is the treatment for tardive dyskinesia caused by typical antipsychotics?
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Sometimes responds to change of dose/medication
(Often acutely worsens with dose reduction) |
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What is the treatment for neuroleptic malignant syndrome caused by typical antipsychotics?
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Stop APD and Hospitalize
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What are the acute side effects of typical antipsychotic drugs? (4)
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1. Sedation (due to histamine receptor blockade)
2. Anticholinergic (low potency = greater side-effct) 3. Orthostatic hypotension (due to α1-adrenergic blockade) 4. EPS |
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What are the side effects due to ACh blockade by typical antipsychotics?
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Dry mouth
Constipation Urinary retention Blurry vision Tachycardia |
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Do low potency typical antipsychotics have a greater or lesser degree of side effects than high potency ones in regards to:
1. Sedation/anticholinergic 2. Hypotension (alpha-1 blockade) 3. EPS |
1. Sedation/Anti-Cholinergic = Greater (potency inversely related)
2. Hypotension = Greater (potency inversly related) 3. EPS = Lesser (potency directly related) |
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Is thioridazine a high, low, or medium potency typical antipsychotic?
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Low
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Is perphenazine a high, low, or medium potency typical antipsychotic?
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Medium
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Is haloperidol a high, low, or medium potency typical antipsychotic?
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High
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Which 5-HT receptor, in particular, do atypical antipsychotics have a high affinity for?
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5-HT2A
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What two things do clozapine carry a special FDA approval for?
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1. Tretment resistant patients
2. Reducing risk of suicide in schizophrenia and schizoaffective disorder |
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Which two antipsychotics have the greatest effect on QTc?
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Thioridazine
Ziprasidone |
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For which patients should two AEDs be considered?
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Those that have failed different AEDs as monotherapy
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What are the four primary/general mechanisms of AEDs?
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1. Block Na currents
2. Enhance GABA-mediated Cl currents 3. Block T-calcium currents 4. Block glutamate-mediated currents |
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What is the rate limiting step in the production of eicosanoids?
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Release of AA by phospholipase A2
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What is the cellular location and activation state of COX?
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Intracellular membrane-bound enzyme
Constitutively active |
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What is the cellular location and activation state of lipoxygenases?
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Soluble cytoplasmic enzymes
Migrate to cell membrane upon cell activation |
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What effect do leukotrienes have on inflammation?
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Monocyte and granulocyte chemotaxis
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What are the effects of prostaglandins and leukotrienes on clotting?
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Thromboxanes activate platelets
Prostacyclins oppose clotting of platelets |
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Which AA derivatives constrict airway smooth muscle?
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Cysteinyl LTs
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Where are COX2 enzymes found?
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Inflammatory cells such as macrophages
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How do NSAIDS exert their antipyretic effect?
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By blocking hypothalamic prostaglandin production
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