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Epilepsy update
Martin Sadler
Issues
Who to treat and when to start? Who needs investigations? What to start with? Treatment aims New drugs What to do when it all goes pear shaped? Epilepsy surgery and gadgets When to stop?
Who to treat
One seizure or two? (24-64% 2 year risk of recurrence)
Benefits of treatment vs natural history (two year risk halved from 40 to 20%, but no effect on longer term remission rate) Overall prognosis (70% 5 year remission, 80% no seizures at 10 years,
at 15 years 50% not on treatment)
What to tell those who do not want treatment Mind over matter
Who to investigate
Any epilepsy commencing after 25 years of age… imaging
Epilepsy under 25 years which cannot be classified as partial or generalised… EEG and imaging
Below 25, EEG and image if not IGE
What to start with
Most adult seizures are focal onsetCarbamazepineValproate, lamotrigine, oxcarbazepine, ?
topiramate (less efficacy, more tolerability?)
Generalised seizuresValproateLamotrigine, topiramate (?better tolerated, less ADR)
Women
40% of patients are women of childbearing age Women with epilepsy account for 0.5% of all
pregnancies 2% women with epilepsy have fits during labour Uncontrolled epilepsy is a greater risk than drug
therapy to mother and baby
Teratogenicity risk
Monotherapy 4-6% Dual therapy 7-8% Polytherapy 15-20% NTD CBZ 0.5-1% VPA 2%+ (? At above 1g/day) Foetal anticonvulsant syndrome with orofacial
clefts, distal digital anomalies and learning disability +/- cardiac defects attributed to several AEDs.
What to do
Secure diagnosis Lowest effective doses Few drugs
Add folate 5mg/d (NB distal neuropore closed 27d, palate fused 47d)
New drugs… retreads
Tegretol retard2/3 efficacy of “regular” CBZ dose for doseDrug levels may be of no value
Epilim chronoDose for dose equivalenceOnce daily dosing
New drugs… old
LamotrigineNa channels like CBZ & PHTOther mysterious mechanisms
Slow build up to avoid rash (up to 10%)Halve dose of LTG if adding VPAUse starter packs for adding into othersNTD rate = CBZ
Further old new drugs
Topiramate 5 mechanisms of action Long half life, can be used once daily Efficacious Recent monotherapy licence Begin v low (15mg sprinkle) and build slowly
Wt loss 10-20% patients (? Add to VPA). Renal stones Teratogenic? Animal studies: distal limb abnormalities Increases oestrogen metabolism
New drugs in UK
Oxcarbazepine“tegretol lite”No self induced metabolism so rapid
introduction possibleMaintenance 1.5X CBZ600-2400mg/day usual
High dose pill needed
New drug
LevetiracetamUnique mysterious mode of actionBroad spectrum including in myoclonia,
absence and photosensitivity
Effective dose 1-3g/day? Wt loss?teratogenicity
Others
Tiagibine Marred by vigabatrin worries Raises GABA at GABAergic synapses Add in for focal onset seizures (50% seizure reduction in 40%
patients in studies)
30mg day divided doses usually No important interactions but half life shortened by
CBZ and PHT so tds needed (use 20mg tds)
Defunct drugs
Vigabatrin Suicidal inhibitor of GABA transaminase thus raising
GABA Effective AED Concentric field reduction in 40-60%
If continued monitor fields every 6 months No interactions No teratogenicity so far 5% depression (esp if rapid changes)
Surgery
Effective if:Discrete lesionClinical seizure type and EEG consistent with
the lesionNot an “important” bit of brainCareful selection needed
80% seizure freedom
Vagal nerve stimulator
Left vagal nerve wrapped by stimulator electrode May be good for drop attacks May reduce seizures in otherwise intractable
patients (similar to adding new AED)
Expensive
Buccal midazolam
As effective as rectal diazepam Easier to administer Off licence at present
Epilepsy specialist nurse sends out information on use
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