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Lidocaine toxicity
-without epinephrine, max safe does is 4mg/kg
-with epinephrine, max safe does is 7mg/kg
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Stages of anesthesia (4)
Stage I: analgesia
Stage II: delirium or excitement with increase resp. rate and BP
Stage III: surgical anesthesia - unconscious w/ muscle relaxation and decreased response to pain
Stage IV: medullary paralysis --> vasomotor and respiratory centers cease --> death
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MOA of IV anesthetics
- -act predominantly at GABA receptors
- -inhibit neurotransmitter --> depresses CNS function
-ketamine is exception because it inhibits NMDA receptors
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Most common used general anesthetic
-Propofol
-most commonly used because faster recovery, rapid onset, and little emesis
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Most potentially life-threatening adverse effect of general anesthesia
-malignant hyperthermia
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General MOA and use (4) of local anesthetics
- MOA:
- -inhibit nerve conduction by inhibiting Na+ channels on neuronal membrane --> prevents conduction of nerve impulses
- Use:
- 1. infiltration anesthesia
- 2. nerve blocks
- 3. spinal anesthesia
- 4. epidural anesthesia
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Dose dependent effects of local anesthesia on nerve function (e.g. sensory, motor, autonomic, etc...)
Pain --> Sensory (deep pressure later) --> motor neurons
small unmyelinated fibers that conduct pain > temp > autonomic function and touch are affected first
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Why do we add epi to lidocaine? which areas cannot get lidocaine with epi?
Epinephrine is vasoconstrictor, which inhibits distribution of lidocaine away from injection site --> prolongs effects of lidocaine
-this allows for smaller doses
-can NOT use in fingers, nose, penis, or toes to avoid ischemia and tissue loss
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Most commonly used intermediate-acting local
anesthetic used for infiltration and topical anesthesia
- Topical:
- 1. tetracaine
- 2. lidocaine
- 3. EMLA cream
- 4. benzocaine (oragel)
- Infiltration:
- 1. lidocaine
- 2. provocaine (novacaine)
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Complications and difference between epidural and spinal anesthesia
- Spinal:
- -injected into lumbar space into CSF
- -for surgery
- -complications: postdural HA
- Epidural:
- -injected into epidural space
- -used for obstetrics during labor
- -more absorption into blood than sipnal
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Which antiviral used for severe RSV?
Ribavirin
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Mechanism of action of antivirals such as acyclovir, which are effective against herpes viruses - other antiherpes antivirals
Inhibit viral DNA synthesis via inhibiting viral DNA polymerase
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Anti CMV drugs- foscarnet and gancyclovir - major AE and MOA
- Foscarnet
- MOA: inhibits nucleic acid synthesis by direct interaction w/ viral DNA polymerase and HIV
- reverse transcriptase
- AE: Nephrotoxicity, hypocalcemia
- Gancyclovir
- MOA: inhibits viral DNA synthesis
- AE:
- -myelosuppression is frequent and reversible; monitor CBC regularly
- -N/V/D, rash, and HA
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The oral drug of choice that covers influenza A, influenza B and H1N1 influenza is which of the following
Oseltamivir (Tamiflu)
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Treatment of Hep C virus (2)
interferon and ribavirin = Rebetron
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Major drugs used for Hep B virus
- 1. Adefovir dipivoxil (Hepsera)
- 2. Lamivudine (3TC)
- 3. Entecavir (new for chronic)
- 4. Telbivudine (Tyzeka) - newest
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Basic classes of Antiarrhythmics
Class I: Sodium channel blockade; increases threshold and decrease velocity
Class II: Beta-adrenergic blockade (propanolol, esmolol, acebutolol); decrease velocity, prolongs refractory period
Class III: Prolong repolarization (K+ channel blockade); powerful and most useful but very toxic
Class IV: Calcium channel blockade (verapamil, diltiazam, bepridil)
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Lidocaine- uses and toxicity
Type IB antiarrhythmic
-useful for acute therapy of ventricular arrhythmias; not for atrial
- AE: most neurologic
- -seizures in high doses
- -hypotension, AV blocks, and other arrhythmias
- -tremor, dysarthria, and ALOC
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Antiarrhythmics that prolong the action potential and prolong the QT interval and torsades de pointes
- 1. Quinidine and other Class IA drugs
- 2. Sotalol and other class III
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Verapamil- effects as an antiarrhythmics (CCB)
Class IV calcium channel blockade
- -blocks slow Ca+ channels in SA and AV nodes
- -slows conduction and prolong refractory period, slows impulses to ventricles
-effective for automatic and reentry tachycardias (SVTs) and to slow ventricular response to atrial fib
-can increase serum digoxin concentrations
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Drugs is/are used to slow ventricular rate in patients with rapid atrial fibrillation
- 1. Digitalis (Digoxin/Lanoxin)
- 2. Verapamil
- 3. Diltiazem
- 4. Beta blockers
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Amiodarone - MOA and major indications, major AE/toxicity
Class III - K+ channel blocker
-affects K+, Ca++, Na_ channels to prolong AP, increase refractory period of all cardiac fibers
- -first line for ventricular arrhythmias during resuscitation
- -orally for resistant and sustained V-tach and V-fib
DI: warfarin and digoxin levels are increased
AE: prolong QT, Long term= pulmonary toxicity (fibrosis), smurf syndrome
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