epilepsy Flashcards
what is the aim of epilepsy control
prevent the occurrence of seizures by maintaining an effective dose of one or more antiepileptic drugs
what should you consider when choosing an antiepileptic drug
- first the presenting epilepsy syndrome
- If the syndrome is not clear, the seizure type should determine the choice of treatment
- note you should also take into account patients other medication, co-morbidity, age, and sex*
what determines the dosage frequency of antiepileptic drugs
The plasma half life.
- frequency of doses should be kept as low as possible to encourage adherence to meds
which antiepileptics can be given once daily due to their long half life
(acronym: LPPP)
- Lamotrigine
- perampanel
- phenobarbital
- phenytoin
how do you switch a patient from one antiepileptic to another
- if first line monotherapy has failed, check the diagnosis again and then consider starting a second drug (monotherapy)
- slowly withdraw the first drug only when the new regimen with the second drug has been established
what are the disadvantages of combination therapy with antiepileptics
increased risk of:
- adverse reactions
- drug interactions
note monotherapy with antiepileptics should be prescribed whenever possible
why should patients/carers be advised to report any mood changes, distressing thoughts/feelings when taking antiepileptics
because all antiepileptics are associated with an increased risk of suicidal thoughts and behaviours
note this can be seen as early as 1 week into treatment
Should a patient taking antiepileptics stop treatment if they are experiencing suicidal thoughts/behaviours
No, do not stop or switch antiepileptic treatment. Seek advice from a healthcare professional if concerned
why are antiepileptic drugs categorised into 3 risk-based categories
to help healthcare professionals decide whether it is necessary to supply a specific manufacturers version of antiepileptic drug
what are the 3 risk-based categories of antiepileptics
name examples of antiepileptic drugs in each category
- CATEGORY 1: ensure patient is maintained on a specific manufacturer’s product.
e. g Carbamazepine, phenobarbital, phenytoin, primidone - CATEGORY 2: need to supply a specific manufacturers product based on clinical judgement + consultation with the patient and/or carer taking into account factors such as seizure frequency, treatment history, and potential implications to the patient of having a breakthrough seizure.
E.g clobazam, clonazepam, eslicarbazepine acetate, lamotrigine, oxcarbazepine, perampanel, rufinamide, topiramate, valproate, zonisamide
- CATEGORY 3: it is usually unnecessary to ensure that patients are maintained on a specific manufacturer’s product as therapeutic equivalence can be assumed.
e. g Brivaracetam, ethosuximide, gabapentin, lacosamide, levetiracetam, pregabalin, tiagabine, vigabatrin
name the antiepileptic drugs (category 1) that you need to make sure a patient stays on a specific manufacturer’s brand
- Carbamazepine
- phenobarbital
- phenytoin
- primidone
what are the symptoms of Antiepileptic hypersensitivity syndrome
name some antiepileptics are associated with this
fever, rash, and lymphadenopathy (enlarged lymph node) are most commonly seen. other signs could be liver dysfunction, renal/pulmonary abnormalities, multi-organ failure.
antiepileptics associated with this: carbamazepine, lamotrigine, oxcarbazepine, phenobarbital, phenytoin, primidone, and zonisamide
note symptoms can start between 1-8 weeks of starting treatment
what should happen if a patient shows symptoms of antiepileptic hypersensitivity syndrome
the drug should be withdrawn immediately, the patient must not be re-exposed, and expert advice should be sought
what normally causes interactions between antiepileptic drugs
hepatic enzyme induction or inhibition
note interactions between antiepileptics are varibale + unpredictable
how do you withdraw a patient taking an antiepileptic
- should be withdrawn under specialist supervision
- Avoid abrupt withdrawal (particularly of barbiturates and benzodiazepines)
- In patients receiving several antiepileptic drugs, only one drug should be withdrawn at a time
why must you avoid abrupt withdrawal especially when a patient is taking barbiturates (e.g phenobarbital) and benzodiazepines (e.g clonazepam, clobazam)
because abrupt withdrawal in these can cause severe rebound seizures
note withdrawal of barbiturates can take months
what are the rules around epilepsy + Driver and Vehicle Licensing Agency (DVLA).
- If a driver has a seizure (of any type) they must stop driving immediately and inform DVLA
- DVLA recommends not to drive during medication changes or withdrawal. if a seizure occurs during this, driving license revoked for 1 year
- after first unprovoked epileptic seizure or a single isolated seizure do not drive for 6 months. Then assessed by specialist as fit to drive
- those with established epilepsy can drive as long as not danger to public + compliant with treatment. Must be seizure-free for at least one year or have no history of unprovoked seizures
- if a seizure occurs whilst asleep, stop driving for 1 year from last seizure date. unless pattern established that seizures only occur during sleep over 1 year
what is the risk of taking antiepileptic drugs whilst pregnant
when is this risk the highest
increased of teratogenicity
highest risk:
- during first trimester
- if patient is taking 2 or more antiepileptic drugs
when is the only time sodium valporate can be used in women of childbearing age
- conditions of the Pregnancy Prevention Programme are met
- alternative treatments are ineffective or not tolerated
name the 2 safest antiepileptic drugs to take during pregnancy
lamotrigine and levetiracetam
what advice would you give to epileptic women planning a pregnancy
- not to stop their antiepileptic treatment without discussing this with their doctor (treatment based on clinical condition + circumstance)
- urgently referred to a specialist for advice and offered folic acid
which contraception is part of the pregnancy prevention programme
The long-acting reversible contraceptives (LARC):
- copper intrauterine device (Cu-IUD),
- levonorgestrel intrauterine system (LNG-IUS)
- progestogen-only implant (IMP)
note some antiepileptic drugs can reduce the efficacy of hormonal contraceptives, and the efficacy of some antiepileptics may be affected by hormonal contraceptives
what is given during the first trimester to reduce neural tube defects from antiepileptics
folate supplementation (folic acid) is advised throughout the first trimester
how do you minimise the risk of neonatal haemorrhage associated with antiepileptics
Routine injection of vitamin K at birth
which antiepileptics can cause withdrawal effects in newborns
some antiepileptic drugs, in particular benzodiazepines (e.g clonazepam, clobazam) and phenobarbital.
TRUE OR FALSE
women taking antiepileptics should not breastfeed
False.
Women taking antiepileptic monotherapy should generally be encouraged to breastfeed. if on combination therapy- seek specialist advice
note withdrawal effects can occur if a mother suddenly stops breastfeeding
what should all breastfed infants from women taking antiepileptics be monitored for
- monitored for: sedation, feeding difficulties, adequate weight gain, and developmental milestones
- if breast-fed infants are suspected of having adverse drug effects, monitor serum-drug concentration
what is the treatment options for Focal seizures with or without secondary generalisation
mnemonic: foCAL
- Carbamazepine and lamotrigine are first-line options. (oxcarbazepine, sodium valproate and levetiracetam can be used if first-line intolerated)
extra info:
- if monotherapy unsuccessful with first line options, consider adjunctive therapy with clobazam, gabapentin, lamotrigine, levetiracetam, oxcarbazepine, sodium valproate, or topiramate
- if adjunctive therapy isn’t successful a tertiary epilepsy specialist should be consulted
what are the treatment options for generalised tonic-clonic seizures
- sodium valproate
- lamotrigine is the alternative if sodium valproate unsuitable (e.g women of childbearing age)
what are the treatment options for absence seizures and syndromes
mnemonic: SEAL
- first line: Ethosuximide, or sodium valproate
lamotrigine is the alternative is both unsuitable - A combination of any two of these drugs may be used if monotherapy is ineffective
what are the treatment options for Myoclonic seizures (myoclonic jerks)
mnemonic: SALT
first line: sodium valproate
- topiramate (has less favourable side effects) and levetiracetam are alternative options
- A combination of two of these drugs may be used if monotherapy is ineffective or not tolerated
which type of seizures are usually seen in childhood or associated with cerebral damage or mental retardation
what is the treatment for them
mnemonic: SLART
Atonic and tonic seizures
Treatment:
- first line: sodium valproate
- lamotrigine can be added as adjunctive treatment
what are epilepsy syndromes
name the 2 type of epilepsy syndromes
specific types of epilepsy that are characterised based on the number of features including seizure type, age of onset, and EEG characteristics
- Dravet syndrome
- Lennox-Gastaut syndrome
Name the 6 types of seizures/syndromes where sodium valproate is the first-line treatment
- generalised tonic-clonic seizures
- absence seizures and syndromes
- Myoclonic seizures
- Atonic and tonic seizures
- Dravet syndrome
- Lennox-Gastaut syndrome
what are Gabapentin and Pregabalin used to treat
- focal seizures with or without secondary generalisation
- neuropathic pain
which antiepileptics should NOT be used in tonic, atonic, myoclonic and absence seizures
- Carbamazepine
- Oxcarbazepine
- Gabapentin
- Pregabalin
this is because these drugs exacerbate these types of seizures
which antiepileptic causes a cleft palate in newborns if taken during pregnancy
topiramate
which antiepileptic increases the plasma concentration of lamotrigine
sodium valproate
which antiepileptic is converted to phenobarbital in the body
Primidone. It is largely converted to phenobarbital which causes it’s antiepileptic effect
Phenytoin has a narrow therapeutic index and the relationship between dose and plasma-drug concentration is non-linear. How does this affect dosage
- small dosage increases in some patients may produce large increases in plasma concentration with acute toxic side-effects
- Similarly, a few missed doses or a small change in drug absorption may result in a marked change in plasma-drug concentration
- note non-linear dose and plasma-drug concentration means that the plasma concentration does not correlate with the dose*
which antiepileptic is used to treat Lennox-Gastaut syndrome (an epilepsy syndrome)
Rufinamide
- topiramate can also be used in adjunctive treatment
what needs to be monitored in patients taking sodium valproate
- liver function tests and full blood count
this is because it has widespread metabolic effects
what is Convulsive status epilepticus
- when a seizure lasts for 5+ minutes
OR
- One tonic-clonic seizure follows another without the person regaining consciousness in between
what are the immediate measures to manage Convulsive status epilepticus
- positioning the patient to avoid injury
- supporting respiration including the provision of oxygen
- maintaining blood pressure
- correction of any hypoglycaemia
how do you treat seizures lasting more than 5 minutes during Convulsive status epilepticus
- intravenous lorazepam (a benzodiazepine) .repeated once after 10 minutes if seizures recur or fail to respond.
- monitor patients for respiratory depression and hypotension
note Intravenous diazepam is effective but it carries a high risk of thrombophlebitis (blood clot formation).
how do you treat seizures lasting more than 5 minutes during Convulsive status epilepticus if there are no facilities for resuscitation
- diazepam can be administered as a rectal solution or
- midazolam oromucosal solution can be given into the buccal cavity
what can be used to treat Convulsive status epilepticus if benzodiazepines have failed to treat it after 25 minutes
phenytoin sodium, fosphenytoin sodium, or phenobarbital sodium should be used; contact intensive care unit if seizures continue
