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1. Answer B. Levitiracetam
Explanation/comment: The above described symptoms and EEG is characteristic of absence seizure and the
following drugs are effective in treating Absence seizure Valproic acid, Ethosuximide,
benzodiazepines, Levitiracetam, and Phenobarbital.
Though Valproic acid is effective in absence seizure it activates CYP: 2C9, epoxide
hydrolase and uridine diphosphate glucuronosyltransferase in hepatic metabolism, hence
not ideal in this child with gilbert syndrome.
Ethosuximide although the drug of choice for absence seizure it acts by blocking the
T-type calcium channels in thalamic neurons in a magnitude effective enough to reduce
the amplitude of threshold spikes preventing bursting and absence seizure activity.
Ethosuximide does not block fast voltage gated sodium channels involved in generalized
seizure, so ethosuximide is ineffective in case of co-existing generalized tonic-clonic
seizures.
There are class IV reports demonstrating that carbamazepine, oxcarbazepine, phenobarbital,
phenytoin, tiagabine, and vigabatrin may worsen or precipitate absence seizures.
Reference: Stuart M. Cain, Terrance P. Snutch T-type calcium channels in burst-firing, network
synchrony, and epilepsy, Volume 1828, Issue 7, July 2013, Pages 1572–1578; Biochimica
et Biophysica Acta (BBA) – Biomembranes.
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2. Answer B. Lamotrigine
Explanation/comment: The issues in this patient is
Antiepileptic drugs that are inducers of the hepatic cytochrome P450 enzyme system
(including phenytoin, phenobarbital, primidone, and carbamazepine) increase the metabolism
of vitamin D. Valproic acid is an inhibitor of the cytochrome P450 system but is also
associated with altered bone metabolism and decreased bone mass. Lamotrigine has not
been associated with bone loss and may be a better choice in this patient.
Reference: Nature Reviews Neurology 10, 485 (2014) doi: 10.1038/nrneurol.2014.154 Published
online 19 August 2014.
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3. Answer D. Topiramate
Explanation/comment: When we go by studies, “The Standard and New Antiepileptic Drugs (SANAD) study” showed
Lamotrigine had the longest time to treatment failure interval, and carbamazepine
had the shortest time interval to failure. But looking into the co-morbid status is
also vital when choosing AED.
Newer AED potential to cause rash includes, Rufinamide, zonisamide (sulpha allergy),
oxcarbazepine, felbamate, and ethosuximide, lamotrigine. Topiramate is ideal for patient
with co-morbid migraine. Patient with chronic pain disorder gabapentin and pregabalin
is preferred.
While choosing AED, avoid drugs which can worsen the co-morbid condition, like avoid
topiramate and zonisamide for patients with nephrolithiasis. Patient with atopic disorder
are prone for developing rash with Lamotrigine and carbamazepine. Topiramate and zonisamide
can increase weight that is already obese. Levitiracetam, which aggravated irritability
and anger outburst.
Reference: CONTINUUM: Lifelong Learning in Neurology: June 2010 - Volume 16 - Issue 3, Epilepsy
-pp 121–135 doi: 10.1212/01.CON.0000368235.64857.cf
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4. Answer D. Continue on lamotrigine and continue breast feed
Explanation/comment: While deciding the potential risk vs. benefit of breast feeding in nursing infant,
conventional drugs like phenytoin, carbamazepine and sodium valproate are considered
safe because they have less penetrance into breast milk.
Gabapentin, lamotrigine, and topiramate, levitricetam, penetrate in significant amount
there are insufficient data to determine whether or not these drugs can clinically
affect infants. However mothers taking, Phenobarbitone, benzodiazepine, are advised
to follow a mixed regimen of breast-feeding and Top feeding for the first 5 to 7 days
postpartum, because of the delayed elimination of AED.
Reference: Harden CL, Hopp J, Ting TY et al. Practice parameter update: management issues for
women with epilepsy – focus on pregnancy (an evidence-based review): III. Vitamin
K, folic acid, blood levels, and breastfeeding: report of the Quality Standards Subcommittee
and Therapeutics and Technology Assessment Subcommittee of the American Academy of
Neurology and American Epilepsy Society. Neurology 2009; 73: 142–149.
Johannessen SI, Helde G, Brodtkorb E. Levitiracetam concentrations in serum and in
breast milk at birth and during lactation. Epilepsia 2005; 46: 775–777.
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5. Answer B. Topiramate
Explanation/comment: Among newer antiepileptic drugs, Lamotrigine, topiramate, rufinamide, clobazam, and
felbamate are effective in treating Lennox-Gastaut Syndrome. But rufinamide and Ezogabine
are potential to cause Q-T prolongation syndrome and Lacosomide causes P-R interval
prolongation. Base line EKG is must before treating LGS, with rufinamide and Ezogabine.
During the course of treatment when the QTc falls below 300 msec, the risk of ventricular
fibrillation is more. Don't choose Rufinamide for patients with familial history of
short QTc interval.
Prolongation of the P-R interval on the EKG was noted to occur in a dose-dependent
manner with lacosamide. A baseline and post-treatment EKG is suggested especially
in patients with cardiac arrhythmias, cardiomyopathies, and drugs with cardiac conduction
effects.
Reference: Practical Neurology Vol. 8, No. 8, November/December 2009.
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6. Answer C. Levitiracetam
Explanation/comment: AEDs that can adversely affect hormonal contraceptives via Hepatic Cytochrome P450
enzyme induction are termed as Enzyme Inducing Anti-Epileptic Drug (EIAED). Plasma
concentration of, oxcarbazepine, Felbamate, Topiramate (>200mg/dl), Lamotrigine are
reduced by 40%–60% in women taking oral contraceptive pills. Drugs like Gabapentin,
Lacosomide, Levitiracetam, pregabalin, Tiagabine, zonisamide found to have no interaction
with hormonal contraceptives.
In a patient who is on EIAED there is a risk of low hormone levels during the pill-free
period which can lead to unplanned pregnancy. Hence, an alternative could be to use
regimes with short hormone-free intervals (4–5 days) or continuous dose medication
for three months or so (tricycling).
Termed as “TRICYCLE CONTRACEPTION”. The Lamotrigine dose may need to be reduced during
the week of withdrawal bleeding.
Reference: Ann Indian Acad Neurol 2015;18:278–283.
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7. Answer D. Tiagabine
Explanation/comment: Of the newer AEDs, only tiagabine undergoes extensive liver metabolism making it
possible to use in regular doses in renal failure. On the contrary, gabapentin and
vigabatrin are excreted almost exclusively by the kidneys with negligible liver metabolism.
Topiramate, when not used concomitantly with enzyme-inducing drugs, is almost 90%
eliminated directly through the kidneys.
Important dose adjustments will be necessary when using gabapentin, vigabatrin, or
topiramate in patients with moderate to severe renal insufficiency. Other newer AEDs
are eliminated by combination of hepatic metabolism and/or direct renal excretion.
Reference: Jorge J. Asconapé, M.D. Seminars in Neurology/Volume 22, Number 1 2002.
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8. Answer A. Perampanel
Explanation/comment: MCRDBPC clinical trials done, demonstrated the beneficial and efficacy of newer AED
in adult onset partial epilepsy syndrome. Out of which four newer AED, with unique
mechanism of action is found useful in treating partial-onset seizure.
The following table gives a brief note on the mechanism of action of these newer AED.
Reference: Jacqueline A. French, MD, FAAN; Deana M. Gazzola, MD; Continuum (Minneap Minn) 2013;19(3):643–655.
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9. Answer C. Levitiracetam
Explanation/comment: While choosing AED in combinations the drug-drug interaction and their side effect
profile tend to increase. The following combinations, which are commonly employed,
are notorious for exacerbating these symptoms of dizziness, imbalance, and diplopia.
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(1) Carbamazepine and Lamotrigine
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(2) Carbamazepine and lacosamide
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(3) Oxcarbazepine and lacosamide
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(4) Lamotrigine and lacosamide.
Reference: Jacqueline A. French, MD, FAAN; Deana M. Gazzola, MD; Continuum (Minneap Minn) 2013;19(3):643–655.
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10. Answer D. Levitiracetam
Explanation/comment: In treating elderly with epilepsy, understanding their pharmacokinetics and physiology
of the other system should be taken care. Older drugs with high protein bound tend
to have higher level of active fraction producing adverse side effects. Effects on
cognition, alertness, and gait stability are of particular concern.
Among newer AED. Oxcarbazepine has been associated with hyponatremia in older individuals,
particularly in those patients on diuretics. Levitiracetam is a broad-spectrum without
much adverse effects, though it produces dizziness and somnolence.
Topiramate has gained FDA approval as first line monotherapy in epilepsy, but it has
an unfavourable cognitive profile in comparison with Lamotrigine. Both Lamotrigine
and topiramate can be used in elderly but need slow titration of dose, hence not useful
where rapid control of seizure is needed.
Tiagabine, zonisamide, pregabalin are recommended as adjunctive AED and not as first
line.
The most common adverse effect with tiagabine is dizziness.
Reference: Gina Mapes Jetter, M.D., 1 and Jose E. Cavazos, M.D., Ph.D., Seminars In Neurology/Volume
28, Number 3 2008.