aeds from the past to present...rescue therapy for aura or sps disadvantage less effecve sedave...
TRANSCRIPT
7/31/09
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Dr. Yotin Chinvarun M.D. Ph.D.
Comprehensive Epilepsy and Sleep disorder Program PMK hospital
Conventional AEDs New AEDs
New AEDs
Pregabalin
NEW
OLD
Pregabalin
1st genera*on AEDs
• Phenytoin • Carbamazepine • Valproate • Phenobarbital • Clobazam
2nd genera*on AEDs
• Felbamate 1993 • Lamotrigine 1994 • Topiramate 1996 • Tiagabine 1997 • Levi*racetam 1999 • Oxcarbamazepine 2000 • Zonisamide 2000 • Pregabalin 2004
AEDs
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Brivaracetam
Eslicarbazepine Fluorofelbamate
Ganaxolone Huperzine
JZP‐4
Lacosamide Licarzepine
Losigamone NS1209
• Re*gabine • Rufinamide
• RWJ 333‐369 (Carisbamate) • Seletracetam
• Safinamide
• SPD421 • S*ripentol • Talampanel • Valrocemide
New AEDs
3rd genera*on AEDs Introduced in the treatment of epilepsy in 1938
Advantage Par*al onset seizure
2 GTCS
Parenteral form and single dose daily
Disadvantage Adverse reac*ons, dose‐related; ataxia, nystagmus, slurred
speech, and dizziness. High‐dose phenytoin can cause peripheral neuropathy, cerebellar atrophy, chronic side effect cogni*ve impairment, gum hypertrophy, course faces, acnes etc
Significant drug interac*on
Phenytoin
Advantage Idiopathic generalized epilepsy Myoclonic epilepsy Par*al seizure Parenteral form
Disadvantage Teratogenicity Side effect; weight gain, tremor, transient hair loss, Endocrine and metabolic dysfunc*ons
Valproate
Advantages Par*al onset seizure
2 GTCS
Disadvantages Common side effect; dizziness, ataxia, Severe drug erup*ons are rare
Significant drug interac*on
Carbamazepine
• Had been used since 1912 Advantages
Par*al onset seizure 2 GTCS Effec*ve in refractory seizure Parenteral form and single dose daily
Disadvantages Seda*on and hypnosis Cogni*ve impairment Significant drug interac*on
Phenobarbital
Advantage Added on par*al seizure
Rescue therapy for aura or SPS
Disadvantage Less effec*ve Seda*ve side effect
Clobazam
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Advantage Highly effec*ve in severe resistance epilepsy Par*al‐onset seizures with or without secondarily generalized seizures (adult‐monotherapy)
Par*al and generalized seizures associated with Lennox‐Gastaut syndrome (children‐adjunc*ve therapy)
Disadvantage Serious side effect: Aplas*c anemia, hepa*c failure Significant drug interac*on Not available
Felbamate
• Advantages
Easy to use, well tolerated, No interac*ons, no enzyme induc*on
When to use it
Par*al seizures
Early add‐on
Useful in the elderly
• Disadvantages
Variable absorp*on
Wide dosage range tds dosing, satura*on effect
Moderate efficacy
Unknown teratogenicity
Gabapentine
• Advantages
Broad spectrum of efficacy, favourable pharmacokine*cs, Favourable cogni*ve profile, fewer interac*ons
Par*al seizure, Idiopathic generalized epilepsy alterna*ve or adjunct to valproate, Symptoma*c generalized epilepsy, Lennox Gastaut Syndrome
• Disadvantages
Rash, especially with valproate (some*me severe)
Slow *tra*on
Interac*on with carbamazepine
Lamotrigine
• Advantages Known mode of ac*on, Favourable pharmacokine*cs, Easy to use, Few
interac*ons, No enzyme induc*on Added on Par*al seizures
Currently rarely used
Infan*le spasms
• Disadvantages
Seda*on
Psychiatric effects
Seizure worsening in some
Irriversibel visual field constric*on
Unknown teratogenicity
Vigabatrin
n Advantages • Broad spectrum of efficacy, Favourable pharmacokine*cs, Few interac*ons, No enzyme induc*on
• Par*al seizures mono/ added on therapy • Symptoma*c generalized epilepsy
n Disadvantages • Weight loss, hypoesthesia • Cogni*ve impairment • Glaucoma, ? cataract • Very slow *tra*on, rapidly *tra*on caused language difficulty
• Unknown teratogenicity
Topiramate
• Advantages
Known mode of ac*on, toxicity mild, No enzyme induc*on
Added on par*al onset seizure
• Disadvantages
CNS side effect, Dizziness
Inducible metabolism Short half life; tds dosing
Unknown teratogenicity Not available
Tiagabine
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n Advantage • No drug interac*on • Well tolerate and highly effec*ve • Par*al seizure, alterna*ve for idiopathic generalized epilepsy
• Parenteral form
n Disadvantage • Side effects: somnolence, asthenia, infec*on, dizziness, headache, depression, UTI
Levetiracetam
n Advantage • Close structure similarly to Carbamazepine but beher tolerated, Fewer drug interac*on
• Par*al onset seizure • 2 GTCS
n Disadvantage • Hyponatremia in 2.5% More commonly in older pa*ents
• 25% cross –sensi*vity with carbamazepine
Oxcarbazepine
Advantage Good bioavailability Par*al seizure 2 GTCS Alterna*ve valproate for myoclonic seizure
Disadvantage Significant drug interac*on, increased by approximately 30‐40%, when given concomitantly with enzyme‐inducing AEDs
Seda*on, fa*gue, dizziness, ataxia, confusion, cogni*ve impairment, including word finding difficulty, weight loss/anorexia, Depression & psychosis has also been reported, renal stone
Zonisamide n FDA approved in early 2009
n Advantage ‒ Add‐on therapy for the treatment of par*al‐onset seizures in adult >
17 yrs with epilepsy. ‒ Demonstrated efficacy and safety when combined with a broad
range of exis*ng AEDs ‒ Oral and IV form
n Mechanism; selec*vely enhances slow inac*va*on of sodium channels and interacts with the neuroplas*city‐relevant target ‐collapsin response mediator protein‐2 (CRMP‐2)
n Disadvantage ‒ * Dizzines ‒ * Nausea ‒ * Diplopi ‒ * Blurring Vision, * Vomi*ng, * Fa*gue, * Ataxia
Lacosamide
• Novel, voltage‐gated sodium channel blocker
• Advantage – Par*al‐onset seizures with or without secondary generaliza*on in combina*on with other an*‐epilep*c drugs
– Responder rate (> or = 50% decrease in seizure frequency) for eslicarbazepine acetate 800 mg and 1200 mg that ranged between 32 percent and 43 percent
– Safety profile was favorable – Incidence of CNS side effects was low.
Eslicarbazepine
• Seizure type
• Epilepsy syndrome
• Pharmacokine*c profile
• Interac*ons/other medical condi*ons
• Efficacy
• Expected adverse effects
• Cost
Choosing AEDs
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• Broad‐Spectrum Agents
• Valproate • Felbamate • Lamotrigine • Topiramate • Zonisamide • Leve*racetam • Rufinamide*
Narrow-Spectrum Agents
Partial onset seizures Phenytoin Carbamazepine Oxcarbazepine Gabapentin Pregabalin Tiagabine Lacosamide*
Absence Ethosuximide
Choosing AEDs
(Broad Spectrum AEDs)
PHT, PB CBZ, OXC
GBP, VGB, PGB
VPA, LTG, TPM, ZNS, LEV, (FBM)
Drug Partial Secondary generalized
I° Tonic-clonic
Absence
Myoclonic
phenytoin + + + - -
carbamazepin
e
+' + + - -
valproate acid + + + + +
phenobarbital + + + 0 ?+
primidone + + + 0 ?+
ethosuximide 0 0 0 + 0
Traditional AEDs
felbamate + + ?+ ?+ ?+
Gabapentin/
Pregabalin
+ + ?+ 0 ?‑
lamotrigine + + + + +/- *
topiramate + + + ? ?+
tiagabine + + ? ? ?
zonisamide + + ?+ ?+ ?+
levetiracetam + + + ?+ +
oxcarbazepine + + ? + - -
Drug Partial 2 GTCS I° GTCS Absence Myoclonic
2nd generation AEDs
Stein and Kanner. Drugs 2009;69:199-222
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Landmark and Johannessen. Drugs 2008;68:1925-1939
Monotherapy for Partial Seizures
Best evidence and FDA indication: Carbamazepine, Oxcarbazepine, Phenytoin, Topiramate
Similar efficacy, likely better tolerated:
Lamotrigine, Gabapentin, Levetiracetam
Also shown to be effective:
Valproate, Phenobarbital, Felbamate, Lacosamide
Limited data but commonly used:
Zonisamide, Pregabalin
Choosing AEDs
• Monotherapy for Generalized-Onset Tonic-Clonic Seizures
• Best evidence and FDA Indica*on: • Valproate, Topiramate
• Also shown to be effec*ve:
• Zonisamide, Levetiracetam
• Phenytoin, Carbamazepine (may exacerbate absence and myoclonic sz )
• Lamotrigine (may exacerbate myoclonic sz of symptomatic generalized epilepsies
•
Choosing AEDs
• Absence seizures
• Best evidence: – Ethosuximide (limited spectrum, absence only) – Valproate
• Also shown to be effec*ve:
– Lamotrigine
• May be considered as second‐line:
– Zonisamide, Levetiracetam, Topiramate, Felbamate, Clonazepam
Choosing AEDs
• Myoclonic Seizures
• Best evidence: – Valproate – Levetiracetam (FDA indication as adjunctive tx) – Clonazepam (FDA indication)
• Possibly effec*ve: – Zonisamide, Topiramate
Choosing AEDs 2nd AEDs VS CBZ in Partial Sz and GTCS Monotherapy
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• Lennox‐Gastaut Syndrome
• Best evidence/FDA indica*on*: – Topiramate, Felbamate, Clonazepam, Lamotrigine, Rufinamide – * FDA approval is for adjunctive treatment for all except clonazepam
• Also effec*ve: – Valproate
• Some evidence of efficacy: – Zonisamide, Levetiracetam
Choosing AEDs
• Simplifies treatment, reduces adverse effects
• Conversion to monotherapy from polytherapy
– Eliminate seda*ve drugs first – Withdraw an*epilep*c drugs slowly over several months
AEDs Monotherapy
Simple partial carbamazepine
lamotrigine oxcarbazepine levetiracetam
Expert’s opinion: Symptomatic epilepsy Expert’s opinion: Symptomatic epilepsy
Meta-analysis of Add-on of New AEDs (Marson et al., 1997, 2001; Otoul et al., 2005)
AEDs and Evidence base