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91 Cards in this Set
- Front
- Back
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Diazepam
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BENZO used to treat "status epilepticus"
(anticonvulsant) |
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Lorazepam
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BENZO used to treat "status epilepticus"
(anticonvulsants) |
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Temazepam (RESTORIL)
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-poorly absorbed, slow onset
-for difficulty falling asleep but not staying asleep |
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Flurazepam (DALMANE)
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-used for a full night's sleep
-paradoxal excitement |
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Triazolam (HALCION)
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-for difficulty falling asleep but not staying asleep
-possible emergence of abnormal thinking or behavior |
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Benzodiazepines
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Flurazepam
Temazepam Triazolam (Diazepam) (Lorazepam) (Estazolam) (Quazepam) |
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What is the mechanism of the benzodiazepine family?
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-act on the GABAa inhibitory system for sedation, antianxiety, anticonvulsant, muscle relaxtion
-the GABA complex is part of a chloride channel opening it and causing hyperpolarization and preventing AP |
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GABA enhancements and inhibition
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-inhibition of GABA synthesis prevents benzodiazepine aciton
-prevention of GABA degeneration enhances benzodiazepine action |
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Uptake, metabolism and excretion of benzodiazepines
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-rapid uptake bc lipophilic
-metabolized in liver, metabolic tolerance -crosses placenta -slow elimination in children and elderly |
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Negative Side Effects of Benzodiazepine
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-CNS --> dizzines, sedation, nightmares and aggression
-GI pain and upset -abuse and cross tolerance -interacts/tolerance with alcohol -addicted mother can have depression and withdrawal |
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Zaleplon
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-similar to Zolpidem
-fast acting, shorter acting, less potent -dependence risks -lacks morning after sedation side effect seen in Zolpidem |
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Zolpidem
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-AMBIEN (CR)
-non-benzo that acts on BZ1 receptor -non anticonvulsant or muscle relaxant -amnesia -high caloric intake -additive effect with of CNS depressants or tri-antidepressants |
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Eszopiclone
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-LUNESTA
-non-benzo -presumed to act on GABA near BZ receptor -headache, sleepiness, bad taste -8hr sleep duration or amnesia will result |
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Ramelteon
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-melatonin receptor agonist
-MT1 regulates sleepiness -MT2 involved in sleep phase shfiting -improves sleep onset not sleep maintenance -no insomnia, withdrawal, or abuse -Fluvozamine increases serum concentrations -liver dysfunction prolongs half life -endocrine changes |
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Trazodone
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-non-tricyclic/SSRI antidepressant that can be used to induce sleep
-less effective than zolpidem -priapism, orthostatic hypotension |
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What is the mechanism of barbituates?
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-depresses postsynaptic potential by blocking Na channels
-increases the duration of the chloride receptors leading to hyperpolarization by binding to GABAa -enhances benzodiazepine binding -reduces glutamate induced excitation |
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Absorption of barbituates
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-diffuses across all membranes
-absorbed in the stomach unionized -the faster absorbing ones (thiopental) are more lipophilic -meningitis and anticholinesterases increase entry |
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Significance of redistribution of barbituates
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short acting ones may not be excreted as fast so you won't get an ultra short action the second time around
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Treating overdose of barbituates
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-Give bicarbonate to put the weak acids in the uncharged form
-diffusion gradient from brain to plasma -also less tubular reabsorption in the kidney -hemodialysis if necessary -no barbituate antagonist |
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Metabolism of barbituates
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-long acting are significantly unchanged
-short acting have their C5 oxidized, N-demethylation and OX of thio compunds -kidney and liver considerations |
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Pharmacological effects of barbituates
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-sleep induction
-anesthesia -inhibit seizure activity (anticonvulsant) -respiratory depression w/out affecting reflexes -slight decrease in HR - BP -reduced contraction in smooth muscle -hyperalgesia -porphyria (negative feedback) |
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What would you treat dependency of barbituates?
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-use phenobarbital to taper off
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Chloral hydrate
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-elderly and children sedation
-without respiratory depression, unless toxic doses -doesn't affect cough reflex -mechanism unclear -irritating to GI -additive with other CNS depressants -displaces oral anticoagulants from plasma protein -tolerance and dependence after two weeks |
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Paraldehyde
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-irritating to GI
-excreted by lungs in patients with liver/kidney failure -may be used for delirium tremens (alcohol withdrawals) |
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Diphenyldramine
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-Benadryl
-only approved antihistamine -in OTC medications -sedative |
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Insomnia treatment and causes
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benzodiazepine:
probably temazepam or zolpidem casues: pain, hormone, emotional disorders, drugs, changes in routine |
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mechanism of general anesthetics
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-interfere with sodium channels and excitatory neurotransmitters by interfering with the membrane ligand-gated ion channel function
-possibly also GABAa and glycine receptors |
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differential sensitivity of nerve tracts
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-stage I analgesia - dorsal horn and spinothalamic tract - analgesia
-stage II hyperactivity - depression of inhibitory pathways - hyperactivity -stage III - depression of ascending RAS pathways and spinal reflexes -stage IV - depression of the medulla.. |
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organ system effects
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-all devrease respiration
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Halothane
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-used to replace explosive agents
-decreased the HR by irritating the ventricles -can't use catecholamines -does not provide skeletal relaxation as the others do |
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Nitrous oxide
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does not anesthetize by itself
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toxicity of general anesthetics
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-halothane has hepatic toxicity
-methoxyflurane has nephrotoxicity -all gaseous and succinylcholine have malignant hypothermia -treat toxicity with dantrolene -abortion risks seem to increase |
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dantroline mechanism
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-alters the excitation-contraction coupling in skeletal muscle resulting in muscle relaxation
-interferes with intracellular release of Ca++ in the sarcoplasmic reticulum.. |
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application for general anesthetics
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-unique bc you can add or remove drug from system
-use ED 50 = MAC -Minimum Alveolar Concentration -the more lipid soluble the more potent the agent -the more soluble in the blood the slower the induction |
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For gaseous agents what are the units measured in?
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partial pressure (proportional to conc)
has to travel lung-->blood-->brain |
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increase the gas concentration of a gaseous anesthetic
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rate of induction increases
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increase alveolar ventilation of a gaseous anesthetic
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increases the rate of induction
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increase the solubility of gaseous anesthetic in blood
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decrease the rate of induction
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increase the cardiac output of a gaseous anesthetic
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decrease the rate of induction
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What determines the direction of flow and the overall equilibrium?
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-partial pressure will flow from high to low
-dissolved gas in blood does not contribute to flow -NO has a low blood solubility, rapid induction -Halothane has a greater solubility in blood, slower rate of induction |
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How does altering ventilation rate affect the induction of agents with greater solubility in the blood?
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-increasing the ventilation rate speeds up the induction
-equivalent to increasing the drug concentration |
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How does altering the pulmonary blood flow affect the induction of agents with moderate to high blood solubility?
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-increased cardiac output increases blood capacity and slows the induction
-you have to slow the blood flow so that more drug can get on and increase the concentration and induction -patients in shock have a decreased cardiac output |
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Elimination of volatile anesthetics
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-same as absorption, fastest in = fastest out
-halothane (15%) to chlorotrifluoroethyl free radical which causes liver damage -methoxyflurane (70%) metabolite may release fluoride ions causing kidney damage |
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Halothane
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-only produces sleep
-reasonable induction -uterine relaxation -NO added for analgesia -succinylcholine for muscle relaxation -cannot use carecholamines |
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Enflurane
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-Medium rate of induction
-good skeletal muscle relaxation -high doses cause resp and circ depression -risk for seizures -not widely used |
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Isoflurane
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-good skeletal muscle relaxation
-pungent odor -progressive resp depression, hypotension -good use with catecholamines |
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Desflurane
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-similar to isoflurane with more rapid recovery and better control
-pungent odor -low volatility so poor induction -tachycardia/hypertension by sympathetic activation |
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Sevoflurane
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-rapid, smooth induction
-even easier control -nausea/vomiting -reacts with CO2 to form nephrotoxic metabolite that releases fluoride ion -good replacement for halothane in children |
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Methoxyflurane
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-good skeletal muscle relaxer with little effect on uterine contractions
-induction is slow and control is difficult -renal damage -resp and circ depression -caesarian section -discontinued from toxicity |
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Nitrous Oxide
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-gas
-only analgesic not anesthesia -can't use where there are air pockets bc N20 replaces N for a greater volume -not irritating, rapid -usually combined, used in dentistry |
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Thiopental
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-rapid and pleasant
-little post-anesthetic excitement or vomiting -causes cough, laryngospasm, or bronchospasm |
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Distribution of Thiopental
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-gets into the brain quickly
-as long as its in there it will anesthetize -it has to go to the brain and then the lean tissues -phenobarbital goes to all the tissues at the same time |
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Propofol
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-similar to thiopental
-rapid induction and good recovery -upbeat mood -little nausea -more hypotension bc histamine is released |
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Ketamine
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-sedation, immobility, amnesia and profound analgesia
-no loss of consciousness -third part experiences -blockage of glutamic acid -incc intracranial pressude and cerebral blood flow -poor muscle relaxant -stimulates cardiovascular -high risk patients (elderly) -some abuse |
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Opiod neurologicald anesthesia
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-Fentanyl
-neuroleptaneasthesia -amnesia and analgesia -sometimes combined -diagnostic exams or minor surgical procedures |
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Etomidate
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-rapid induction and fast recovery
-minimal CV or respiratory change -adrenocortical suppression -myoclonia (arm flexing) |
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Anesthetic Benzodiazepines
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Midazolam - water soluble
-high incidence of amnesia -short term procedures Lorazepam - for antegrade amnesia |
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Characteristics of Epilepsy
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Any of the following:
-alteration in consciousness -convulsive moments -loss of muscular tone -disturbance in feeling/behavior |
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Tonic-clonic seizures
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-bird-like cry
-tonic then clonic -loss of consciousness -high amplitude EEG spikes -may lose sphincter control |
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Absences
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-only a few seconds, just blank out
-"spike and dome" |
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Minor motor seizure
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-akinetic
-loss of back muscle tone so the patient falls -jackknifing movements -infantile spasms: jerky |
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Partial (focal) seizures
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-psychomotor epilepsy
-alterations in behavior, perception -behavior -can't control certain movements that are triggered -usually not aware of what they are doing |
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Basic Mechanism of Anti-seizures
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-the problem is synchronous neural discharge
-drugs depress the epileptic focus by increasing the refractory period and decreasing repetitive firing -or alter synaptic transmission to inhibi8t the discharge away from the focal point -or reduce excitatory NT's |
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Phenytoin Mechanism
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-tonic/clonic, status epilepticus, partial complex and focal seizures
-depresses all membrane excitability by reducing Na conductance |
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Phenytoin Use
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-cautiously increase dose to achieve therapeutic levels
-this avoids toxic effects -agents that inhibit its metabolism: chloramphenicol, sulfonamide -agents that stimulate its metabolism: carbamazepine, phenobarbital |
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Phenytoin Side Effects
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-CNS and GI side effects
-gingival hyperpllasia -hirsutism: growth of body hair -blood dyscrasias |
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Fosphenytoin
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-pro-drug for phenytoin
-freely soluble in IV fluids -for status epilepticus |
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Carbamazepine Uses and Mechanism
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-drug of choice for partial complex and focal seizures
-neuropathix pain -inhibits Na conductance and presynaptic transmission |
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Carbamazepine Interactions
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-can't be used with MAO inhibitors bc it resembles a tricyclic antidepressant
-decreases levels of other anticonvulsants -erythromycin, isoniazid inhibit its metabolism |
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Carbamazepine Absorption and Side Effects
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-not a good correlation between plasma levels and seizure control
-converted to an active metabolite -CNS and GI side effects -erythematous skin rash -hyponatremia -aplastic anemia and agranulocytosis |
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Oxcarbazepine
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-similar to carbamazepine but w/lower toxicity
-long-acting metabolite -induces hepatic enzymes less -sleepiness, dizziness, ataxia -nausea, vomiting, rash |
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Phenobarbital Uses
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-tonic/clonic and other seizures
-Historically for seizures in children |
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Phenobarbital Mechanism
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-potentiates GABA --> hyperpolarization
-reduces Ca dependent NT release -antagonizes glutamate excitatory pathways |
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Phenobarbital Side Effects and Interactions
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-CNS: sedatin, nystagmus and ataxia
-megaloblastic anemia -interacts with phenytoin, carbamazepine and valproic acid |
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Primidone
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-Structurally similar to phenobarbital
-Action is similar to phenytoin -partial and generalized tonic/clolnic seizures -converted to phenobarbital, but significant action is from primidone |
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Ethosuximide
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-1st choice for uncomplicated absence seizures
-unclear mechanism, may affect Ca channel activity and NT release -well absorbed and not bound to protein so few interactions -valproic acid may affect it -CNS/GI toxicity |
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Valproic Acid Mechanism
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-increased GABA by inhibiting catabolic enzymes
-voltage sensitive Na channels -may block NMDA receptor mediation excitation -rapidly absrobed and highly protein bound |
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Valproic Acid Use
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-myoclonic seizures
-secondary for generalized absence seizures |
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Valproic Acid Side Effects
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-CNS: but few than other drugs
-GI: abdominal pain, weight gain -hair loss, curling -sudden liver failure so second to ethosuximide for absence seizures |
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Valproic Acid Interactions
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-increases in phenobarbital levels
-inhibits platelet aggregation -caution with other anticoagulants |
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Benzodiazepines for Anticonvulsants
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Act through GABA
Clonazepam: for absence and myoclonic seizures Diazepam or Lorazepam: for status epilepticus and febrile seizures |
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GABAergic agents
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Gabapentin - analog of GABA, also neuropathic pain
Pregabalin - analog of GABA, also used |
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Valproic Acid Interactions
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-increases in phenobarbital levels
-inhibits platelet aggregation -caution with other anticoagulants |
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Benzodiazepines for Anticonvulsants
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Act through GABA
Clonazepam: for absence and myoclonic seizures Diazepam or Lorazepam: for status epilepticus and febrile seizures |
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GABAergic agents
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Gabapentin - analog of GABA, also neuropathic pain
Pregabalin - analog of GABA, also used NP pain with diabetes Vigabatrin - inhibits GABA catabolism, partial seizures Tiagabine - inhibitor of GABA reuptake, doesn't alter serum concentrations of other drugs |
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Lamotrigine
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-add on drug for partial seizures
-blocks excitatory NT's |
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Felbamate
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-blocks excitatory NT's at NMDA
-life-threatening aplastic anemia |
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Keppra
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-adjunctive treatment for partial seizures
-initiated at maintenance dose |
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ACTH
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-for infantile spasms
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Zonisamide
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-adjunctive treatment for generalized and partial seizures
-low interaction with other meds |
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Topiramate
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-blocks Na conductance and potentiates GABA
-inhibits action of kainate: glutamate receptor agonist -can't use with glaucoma or myopia |
