Download epilepsy

Michelle Knight and Aideen Tarpey
Epilepsy Specialist Nurses – Dorset Epilepsy Service
• ‘Epilepsy’ is not a diagnosis per se but a symptom
• Annual incidence of around 50 cases per 100,000
• Most common serious neurological condition
• 40 types of seizures
• Higher prevalence in young and elderly
• Increased mortality & morbidity:
– Standardised mortality ratio 2-4 times matched background:
– Risk of death 23 times higher if uncontrolled seizures
– Increased unemployment and dependency
– Significant adverse side-effects associated with AEDs
SEIZURE TYPES
• Seizures previously classed as “Grand
Mal” or “Petit Mal”
• These terms were considered too general
as over 40 types of seizures
• Reclassified in 1981 by ILAE
GENERALISED
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Tonic – clonic
Tonic
Atonic
Absence
Myoclonic
PARTIAL
• Simple – Partial
• Complex – Partial
• Secondary Generalised
Is treatment necessary?
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Cumulative risk of single seizure 5%
Risk of 2nd seizure 50-80% within 3 years
75% of these recur within 1 year
Focal & tonic-clonic seizures more likely
Syndromic diagnosis may provide more
information
After 2-5 years of seizure freedom:
60% seizure free (vs 80% of those still on AED)
Available anticonvulsants
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Acetazolamide (1952)
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Phenobarbital (1912)
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Benzodiazepines (1950’s)
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Phenytoin (1952)
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Carbamazepine (1964)
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Piracetam (1967; myoclonus 1978)
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Ethosuximide (1958)
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Rufinamide (2008)
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Felbamate (USA – 1980’s)
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Stiripentol (2007)
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Gabapentin (1990’s)
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Tiagabine (1990’s)
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Lacosamide (2008)
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Topiramate (1990’s)
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Lamotrigine (1990’s)
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Valproate (late 1960’s)
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Levetiracetam (2000)
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Vigabatrin (1990’s)
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Oxcarbazepine (1980’s; UK 2000)
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Zonisamide (Japan 1970’s)
Available AEDs
25
20
15
10
5
0
1900
1950
2000
Starting medication
• Choice of AED depends on individual factors
• Start low, go slow
• If not tolerated or not effective substitute alternative
• At least two trials of single agent at reasonable dose
• Little additional benefit for more than 2 agents
First Line Treatment
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Carbamazepine
Lamotrigine
Sodium Valproate
Topirimate
Oxcarbazepine
Levetiracetam
Ethosuximide
Phenytoin
Second line treatment
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Acetazolamide
Clobazam
Clonazepam
Gabapentin
Lacosamide
Phenobarbitone
Phenytoin
Piracetam
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Zonisimide
Pregabalin
Vigabatrin
Tiagabine
Stiripentol
Rufinamide
Primidone
Topirimate
Levetiracetam (Keppra)
• Monotherapy for partial onset seizures with or without
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secondary generalisation in patients from 16 years of
age
Adjunctive therapy for partial onset seizures with or
without secondary generalisation in adults and children
from 4 years of age
Adjuctive therapy for myoclonic seizures in adults and
adolescents from 12 years of age with JME
Adjunctive therapy for primary generalised tonic-clonic
seizures in adults and adolescents from 12years of age
with Idiopathic Generalised Epilepsy
The future……
• Once daily preparation of Sodium
Valproate Chrono (Episenta) already being
widely used
• Zebinix – Once daily, evolved from
Carbamazepine (but without many of the
side effects) adjunctive therapy
• More drugs in development……
Response to medication
• Remission on single drug 60-80%
• Dose required often relatively modest
• Failure on first drug due to:
– Adverse reaction - 48%
– Lack of efficacy - 21%
• 92% who go into remission do so in 3yrs
• Compliance with medication may be a significant issue
• Interactions with other medications
Rescue medication
• Diazepam
• Buccal midazolam (Epistatus)
• Emergency care plan and training needed
in administration, epilepsy awareness and
first aid.
Generic vs. branded
• “changing the formulation or brand of AED
is not recommended because different
preparations may vary in bioavailability or
have different pharmacokinetic profiles
and, thus, increased potential for reduced
effect or excessive side effects.”
NICE
Contraception
• Enzyme inducing drugs (carbamazepine,
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oxcarbazepine, phenobarbital, phenytoin, primidone,
topirimate and lamotrigine) reduce the effectiveness
of hormonal contraception
Lamotrigine may make the COC less effective and
the COC may reduce the amount of lamotrigine in
the blood stream (HRT may also do the same)
Contraception not affected by AED’s include Barrier
methods, Depro-Provera, IUD’s and IUS (mirena coil)
Morning after pill – if on enzyme inducing drug, need
3milligrams of levonorgestrel instead of 1.5
milligrams
Pregnancy
• Women of childbearing age with epilepsy should
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take folic acid 5 milligrams a day. This should be
continued throughout the pregnancy. (folic acid may
interact with Phenytoin, phenobarbitone and
primidone making them less effective)
Sodium valproate – PCOS risk may increase if taken
from an early age
Pre-conceptual counselling – first three months of
pregnancy, risk is greatest
Sudden stopping of medication not advised
Balance of risk of seizures / drug therapy
MCM – damaged spine, heart problems, cleft palate,
hernia. Minor malformations
MCM’s
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UK Epilepsy and Pregnancy register
General population risk is 1-2 babies in 100 will have MCM
Mothers who take AED’s, 4 in 100 will have MCM
Higher risk if more than 1 AED
Sodium Valproate is thought to carry highest risk (look at
rationalising – Chrono)
Fetal anti-convulsant syndrome
Breast feeding
Seizures during pregnancy
Vitamin K 10-20mg during last month of pregnancy if on
enzyme inducing drug
Pethadine not recommended
Management once baby is born
Osteoporosis and AED’s
• Using AED’s long term can be a risk factor
for bone loss and fractures
• In particular, carbamazepine,
phenobarbital, phenytoin, primidone and
sodium valproate
• Assess each patient and if necessary, refer
for bone density scan
Thank you!
Any Questions?
Dorset Epilepsy Service – 01202 442231 / 01202 448486
[email protected]