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20 Cards in this Set
- Front
- Back
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Benzodiazepines differ from Barbiturates in that benzodiazepines ....
a) facilitate the action of GABA on neuronal Cl- channels b) have anticonvulsant activity c) may induce physical dependence d) have a higher margin of safety than barbiturates |
Answer is D
Benzodiazepines diazapam and clonazapam increase FREQUENCY of GABA-mediated Cl- channel openings Barbiturates phenobarbital, primidone PROLONG GABA-mediated CL- channel openings |
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Which of the following agents is the primary drug for the treatment of major motor seizures and partial seizures?
a) Clonazepam b) Ethosuximide c) Valproate |
First line dug for tonic-clonic, myoclonic and absence seizures (motor seizures) is Valproate
Ethosuximide is good for Ca2+ channel blockade of T type currents and is effective for treating absence seizures. Prevents oscillations between thalamus and cortex that are generated in thalamus by T-type Ca++ currents |
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Which of the following effects is associated with benzodiazepines?
a) paradoxical excitement b) ataxia c) sedation d) amnesia e) all of the above |
All of the above are true
Diazapam and clonazapam are used to treat status epilepticus it works on GABAa receptors to increase FREQUENCY of opening causes CNS sedative, tolerance and dependence Paradoxical hyperexcitability in children |
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Which of the following agents may be considered a drug of choice for the treatment?
a) Phenytoin b) Phenobarbital c) Carbamazepine d) Ethosuximide |
Ethosuximide is the drug of choice for absence seizures.
Carbamazepine, phenytoin, and phenobarbital are used to treat partial seizures and tonic-clonic seizures; phenytoin is also used to treat status epilepticus (diazapam is first line treatment) |
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A 19-yo epileptic student was brought to the ER in a coma after taking a whole bottle of her antiepileptic pills (phenytoin). On physical exam she is unconscious, hyptensive, hypothermic and bradypneic. What features of phenytoin caused these findings?
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Phenytoin is a barbiturate that works on keeping GABAa mediated CL-channel opening. Barbiturates induce the CYP450 enzyme system of liver. In overdose, death may ensue due to severe CNS depression (respiratory depression or aspiration pneumonia)
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Patient comes to the clinic with complaint of severe, sharp pain on the left side of her face that radiates to the corner of her eye and is triggered by mastication or cold exposure.
What are her symptoms indicative of and what would be an appropriate treatment? |
She has trigeminal neuralgia due to her MS. Prescribe Carbamazepine for treatment.
Side effects include blurred vision, dry mouth, ataxia, aplastic anemia, hepatotoxicity If these occur try switching to GABApentin which also treats neuropathic pain |
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A 26 yo woman develops a seizure disorder characterized by recurrent contractions of the muscles in her right hand which then spread to her right arm and to the right side of the face "jacksonian march".
Consciousness is not impaired attacks usually last for 1-2mins WHich of the following drugs is least likely to be useful in the treatment of this patient? a) Carbamazepine b) Ethosuximide c) Lamotrigine d) Phenytoin |
This patient had a simple partial seizure because there was no loss of consiousness and presented with tonic-clonic on one side so it was partial (probably focal to left lobe)
Carbamazapine (Na channel blockade) Phenytoin (Na channel blockade) Lomatrigone (add on for partial seizures) all treat tonic-clonic partial seizures Ethosuximide is used to treat absence seizures by reducing Ca2+ transport T-type. Absence seizures is accompanied by loss of consciousness |
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A 9-yo child is having learning difficulties at school. He has brief lapses of awareness with eyelid fluttering that occur every 5-10 mins. EEG studies reveal brief 3Hz spike and wave discharges appearing synchronously in all leads. Which of the following drugs would be effective in this child but has the disadvantage of causing sedation and tolerance?
a) Clonazepam b) Diazepam c) Ethosuximide d) Phenobarbital e) Valproate |
Clonazepam: Benzodiazepine
Diazepam: Benzodiazepine Benzodiazepine increase freq of GABA-Cl-channel opening Ethosuximide: Ca2+transport decreased by blocking T-type currents used to treat absence seizures Phenobarbital: Barbituates Barbituates prolong open time of GABA-Cl-Channel opening Valproate: reduces Na+ conductance and increases GABA levels in brain Clonazepam and Phenobarbital can be useful agains generalized seizures, but may have GREATER SEDATIVE effects and Clonazepam can cause TOLERANCE after ~ 6 months. Increased sedative effect would not be useful in a school age child who has lapses in awareness and eventually would be ineffective. Ethosuximide would be more effective |
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Which of the following statements concerning proposed mechanisms of action of AEDs is false?
a) Diazepam facilitates GABA-mediated inhibitory actions b. Ethosuximide selectively blocks K+ ion channels in thalamic neurons c. Phenobarbital has multiple actions, including enhancement of effects of GABA, antogonism of Glutamate receptors and blockade of Na ion channels. d. Phenytoin prolongs the inactivated state of the Na ion channel |
Diazepam is a benzoadiazepine which increases frequency of GABA-CL-channel opening.
Ethosuximide blocks Ca++ transport by inhibiting T-type currents in thalamic neurons. Valproate augement K channels Phenobarbital is a barbiturate that prolongs GABA-mediated Cl-channel opening and has some blockade of voltage-dependent Na channels. Phenytoin inhibits Na channels |
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Which of the following AEDs is most likely to elevate the plasma concentrations of other drugs administered concomitantly?
Carbamazepine Diazepam Phenobarbital Phenytoin Valproic Acid |
Drug Interactions
Carbamazepine- induces CYP450 and its own metabolism, leads to metabolism of other drugs Diazepam enchance action of other CNS depressants Phenobarbital- stimulates CYP450 and causes severe depression when combined with EtOH or Benzodiazepines Phenytoin- Stimulates CYP450 so can increase metabolism of some drugs Valproate- displaces phenytoin from plasma proteins, inhibits metabolism of phenobarbital, phenytoin, carbamazepine because it is a CYP INHIBITOR |
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A young woman suffers MC jerking with no overt signs of neuro deficit. No history of generalized TC seizures. To control seizures w/o excessive sedation which is the most appropriate drug ...
management of this pt requires what tests... |
All AEDs are CNS depressants!Clonazepam is a benzodiazepine that causes CNS sedation. Also CNS sedation is caused by Barbituarate -Phenobarbital, OXC, Carbamazapine, Phenytoin. Valproate does not cause CNS sedation.
It causes GI distress, hepatotoxicity, teratogenicity and inhibition of drug metabolism. The pt. should be monitored for Abdominal pain and heart burn, liver enzymes, pregnancy and patient should avoid barbiturates because Valproate inhibits it metabolism and it could lead to severe CNS depression and death. |
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With chronic use in seizure states, the adverse effects of this drug include coarsening of facial features, hirsutism, gingival hyperplasia, and osteomalacia.
a. carbamazaepine b. ethosuximide c. gabapentin d. phenytoin e. valproate |
Carbamazepine side effects:
diplopia, ataxia, agranulocytosis, aplastic anemia, rashes, bone marrow supp Ethosuximide side effects: GI distress, lethargy, headache, hiccup, vomiting, Lupus is rare Gabapentin side effects: drowsiness, weight gain, renal adjustments, irritability in children Phenytoin: nystagmus, diplopia, ataxia, sedation, gingival hyperplasia, hirsuitism, CNS sedation Valproate side effects: GI distress, hepatotoxicity, teratogenicity, inhibition of drug metabolism |
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Which drugs are severely contraindictated during pregnancy?
causes teratogenicity and birth defects |
Valproate may cause birth defects
Phenobarbital leads to congenital malformation Carbamazepine is teratogenic Phenytoin is teratogenic Clonazepam appears in breast milk |
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Which of the following statements about phenytoin is correct?
a. displaces sulfonamides from plasma proteins b. drug of choice in myoclonic seizures c. t1/2 is increased if used with phenobarbital d. toxicity may occur with only small increments in dose |
Phenytoin is a sodium channel blocker
it is 90% protein bound eliminated by first order kinetics at low doses and zero order at high doses therapeutic plasma concentration is 10-20ug/ml. There isn't a linear relationship between dose and plasma concentration due to the fact that heaptic enzymes can become saturated. Therefore small increases in the adult dose above 360mg/day can lead to toxic blood concentration. side effect is nystagmus |
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Why is Carbamazepine used to treat Absence seizures and what is the danger?
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Carbamazepine is used to treat the automatisms of absence seizures but it can exacerbate absence and myoclonic, seizures
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Why are blood levels of AEDs measured several times during the day for patients on Valproate and Ethosuximide therapy?
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these drugs have a narrow therapeutic window
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If a patient is on Ethosuximide and Valproate what alternative drugs can be used and what side effects do these drugs have?
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Alternative drugs for the management of absence seizures
Lamotrigine, topiramate and zonisamide are effective against tonic-clonic, absence and tonic seizures. Clonazepam is useful against generalized seizures. Clonazepam leads to TOLERANCE. Lamotrigone use in children is associated with life threatening dermatitis-Stevens Johnson syndrome. Topiramate causes a decrease in IQ |
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A 17-yo boy experiences a tonic-clonic seizure at school. The seizure continues as he is being transported to the ER, and the boy does not regain consciousness. Shortly after arriving at the hospital, the patient experiences another seizure. Which of the following is the drug of choice for treatment of this patient?
a. Ethosuximide b. Diazepam c. Carbamazepine d. Valproate |
Treatment
Diazepam followed by phenytoin or phenobarbital |
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Which of the following medications is indicated for the treatment of generalized tonic-clonic seizures?
a. Carbamazepine b. Valproate c. Phenobarbital d. All of the above |
tonic-clonic, myoclonic, and absence seizures- first line drug is often Valproate
Phenytoin and Carbamazepine are effective on tonic-clonic seizures but not other types of generalized seizures |
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Which of the following effects is associated with the chronic use of phenytoin?
a. tremor b. sedation c. nystagmus d. hair loss e. all of the above |
Adverse effects of Phenytoin
CNS sedation drowsiness ataxia confusion insomnia nystagmus gum hyperplasia hirsutism |
