Epilepsy Flashcards
Which antiepileptics have long half lives and so can be given OD at bedtime?
lamotrigine, perampanel, phenobaribtal and phenytoin
Can multiple antiepileptics be used together?
Ideally, monotherapy should be prescribed. If one drug fails, it should be slowly withdrawn and another antiepileptic started as concurrent use of multiple antiepileptic can lead to DDI and ADRs. Wherever possible use a single AE drug
If a patient is on an AED for an alterative indication e.g. neuropathic pain should the brand be specfied?
No - only a requirement if used for epilepsy
What AED are in risk category 1?
PPP C Phenyoin Primidone Phenobaribtal Carbamazepine
What is the advise with category 1 AED?
Phenytoin, primidone, carbamazepine and phenobarbital - Drs are advised to maintain patient on a specific manufacturers product
What AED fit into category 2?
Clobazam, Clonazepam, Eslicarbazepine, Lamotrigine, Topiramate, valporate, zonisomide, oxcarbazapine
What is the advise for prescribing category 2 AEDs?
Need for continued supply of a particular maufacturers product should be based on clinical judgement and consultation wiht the pt
Example of Category 3 AEDs
Ethosuximide, Gabapentin, Lacosamide, Levetiracetam, Vigabtrin, Birvaracetam
What is the prescribing advise for Category 3 AEDs?
unnecessary to maintain on the same brand as therapeutic equivalance can be assummed
Whast is antiepileptic hypersensitivty syndrome?
A rare but fate syndrome associated with some AEDs. Symptoms start between weeks 1 and 8 weeks of exposure and include fever, rash, lymphadenopathy. The AED should be withdrawn immediately and pt should NOT be reexposed
What drugs can hold the risk of Antiepileptic hypersensitivity syndrome?
Carbamazepine, Lamotrigine, Oxcarbazepine, phenobarbital, phenytoin, primidone, rufinamide
The MHRA alerted that all AED can hae a small increased risk of what?
suicidal thoughts andd behaviour - after 1 week of treatment. Advise pt to seek medical advice if they develop any mood changes, distressing thought or feelings about suicide
What can happen if bariburates or benzodiazepnines are withdrawn abruptly?
Withdrawal seizures
What must a driver do if they have a seizure?
Stop driving immediately and inform the DVLA
How long must a driver not drive for following their first unprovoked oor single isolated seizure?
6 months (driving may then resume following assessment by a specialist)
Can patients wiht established epilepsy drive?
Yes, provided they are not a danger to themselves of the public and are compliant wiht treatment follow up and have no history of unprovoked seizures
Patients who have had a seizure whilst asleep cannot drive for how long?
1 year - unless a history of pattern of sleep seizures occuring only ever while asleep has been established over the course of 1 year or an established pattern of purely asleep seizures can be demonstrated over the course of 3 years if the patient has previously had awake seizures
If a patient is having medication changes or withdrawl should they drive
No and for 6 months after their last dose. If a seizure occurs due to withdrawal their license is revoked for 1 year
What is the risk of pregnancy and epilepsy?
Teratogenicity of AEDs espeically in 1st trimester
What AED has the highest risk of teratogenicity?
Valporate
developmental disorders 30-40%) malformations (10%
What must a women be under to be on valporate?
PPP (pregnancy provention programme)
What risk does topiramate hold in pregnancy?
Risk of malformations e.g. cleft palate
If a patient becomes pregnant whilst taking AEDs and cannot withdraw what is advised to be given?
folate 5mg ( to cover for NTD)
Foetal growth should be monitored in patients taking which 2 AEDs
Topiramate and levetiracetam
What condition should women in their 2nd trimester experiencing seizures be checked for before chaging AEDs?
eclapsia
Injection of what medication can reduce the risk of neonatal haemorrhage when giving birth if mother is on AEDs?
Vitamin K
All women with epilepsy taking antiepileptics or not should be encouraged to notify who?
Epilepsy and pregancy register
Can a mother breastfeed when on AEDs?
Yes if on monotherapy, if on combo therapy specialist adivce should be sought. Monitor infant for sedation, feeding difficulties, adepquate weight gain and developmetal milestones
What antiepileptics have an established risk of drowsiness in BF babies?
Phenobarbital, primidone, Benzos
First line drug(s) for Focal seizures with or without secondary generalisation
Carbamazepine or Lamotrigine
First line drug(s) for tonic clonic seizures
Valporate or lamotrigine if young female
First line drug(s) for absence seizures
Ethosuximide or valporate
First line drug(s) for myoclonic seizures
Valporate or if premenopausal topimarate/levetirCETAM
Drug of choice in atonic and tonic seizures
Sodium valporate - if contraindicated seek specialisdt advice
Tonic / atonic - respond poorly to tradition meds
Examples of epilepsy syndromes
Dravet, Lennox-Gastaut syndrome
What AED is also licensed for generalised anxiety disorder?
Pregabalin
What is primidone the pro-drug of?
Phenobaribtal
what is meant by Phenytoins ‘non linear kinetics’
A small dosage increase in some patients may produce a large increase in plasma concentrations with acute toxic side effects
What is the pro drug of Phenytoin and why can it be benefitical to use?
Fosphenytoin - can be given IM (unlike phenytoin) so good if parenteral access only
What should female patients be co-prescribed/advised when on topiramte?
Should have adequate contraception - risk of Cleft palarte malformations
what 2 monitoring parameters are important with valporate?
LFTs and FBC
Valporic acid (semi sodium valporate) is not used in epilepsy - what disorder is it used in?
acute mania associated with bipolar disorder
What drug can be used to treat epilepsy associated with menstration?
Acetylzolamide (a carbonic anhydrase inhibitor)
What drug is used in the adjunct treatment of cortical myoclonas?
Piracetam
In status epilepticus, seizures lasting >5 mins should be treated with what drug?
Lorazepam IV ( repeat once after 10 mins if seizures recur) IV diazepam can also be used but carries risk of thrombophlebitis - if resus facilities are not avaliable, oromucosal midazolam or recal midazolam can be given
If after 25 minutes, seizures are not controlled - what drugs should be used?
Phenobaribtal or Phenytoin or fosphenytoi
What antipyretic can be used in febrile convulsions
paracetamol
what electrolyte abnormality can carbamazapine cause/
hyponatreamia
What should patients be advised to report when starting on carbamazepine?
report any signs of blood, liver or skin disorders e.g. mouth ulcers, fevers,rash, bruising or bleeding
What supplementation is sometimes advised to be used alongside immobile patients on carbmazepine?
calcium (bone fracture risk)
What pre-treatment screening is required with carbamazapine?
HLA-B*1502 allele in indivduals with hans chineses or thai origin ( risk of SJS)
optimum plasma level for carbmazepine?
4 -12 mg/L
What shuld be monitored when givine Fosphenytoin?
HR, BP, RR, ECG and observe patient for 30 mins post infusion due to cardiovascualr reaction reported with its use
what are the 2 MHRA warnings associated with Gabapentin?
- Risk of severe respiratory depression
2. Risk of abuse and dependance (reclassified to CD3)
what is the dose equivalanence of phenytoin sodium:phenytoin base>
PS 100mg = 92mg PB
MHRA alert: risk of deth and severe harm from error of injectable XX - what is drug XX?
Phenytoin
How should phenytoin be given if patient is enterally fed?
break in feeding 2 hours before and after dose
Side effects of Phenytoin
Gingival hyperplasia, Agranulocytosis, bone fracture, hair changes, pneumonitis ( oral route), bradycardia, hypotension
Overdose signs of phenytoin
nystagmus, diplopia, slurred speech, hyperglycaemia, confusion
what fraction of phenytoin should be monitored?
Unbound fraction
Why is phenytoin cautioned in heptatic impairment?
Phenytoin binds to albumin - risk of accumulation due to decrease PPB, hypoalbuminaemia or hypobilirubinaemia
optimum level of plasma phenytoin
10-20mg/L
in neonates < 3 months, the optimum level of phenytoin is reduced due to reduced protein binding. What is the recommended plasma level?
6-15mg/l
how should IV phenytoin be given?
Into a large vein
other than epilepsy, what can valporate be used to in?
Prophylaxis of migraine + mania
What must be updated annualling in females taking valporate?
Annual risk acknowledgement form - to support compliance to the PPP
Side effects of sodium valporate
Alopecia, weight gain, agitation, abdominal pain. menstrual infrequencies
What should be routinely monitored during valporate therapy?
LFTs - baseline + 6 months
FBC baseline
What AED has been associated wihth acute myopia with secondary angle closed glaucoma?
Topiramate - occurs within 1 month of treatment
What AED can cause weight loss?
Zonisamide - monitor weight throughout treatment
What AED is contraindicated in sulfonamide hypersensitivity?
Zonisamide
optimum plasma phenobarbital levels
15-40mg/L
What is the antidocte to midazolam / Lorazepam overdose?
Flumazenil
