Epilepsy Flashcards
What are the MHRA warnings for anti-epileptics
- Risk of suicidal thoughts
- Some anti-epileptics should not be switched between different manufacturers products.
What are the category 1 drugs?
Carbamazepine, Phenytoin, Primidone, Phenobarbital
What does category 1 mean
They need to be maintained on a specific manufacturers brand.
What is anti-epileptic hypersensitivity syndrome?
Rare and potentially fatal syndrome that is associated with some anti-epileptics
What drugs are associated with anti-epileptic hypersensitivity syndrome?
Carbamazepine, Phenytoin, Primidone, Phenobarbital, Laccosamide, Lamotrigine, Oxecarbazepine and Rufinamide (cat 1 and LLOR)
When do symptoms show of anti-epileptic hypersensitivity syndrome?
Usually start between week 1 and 8 of exposure and can be fever, rash and lymphadenopathy
Withdraw drug immediately, do not restart and seek expert advice immediately.
What are the main interactions associated with anti-epileptics?
Complex and may cause toxicity without added anti-epileptic effect
Caused by hepatic enzyme induction or inhibition, displacement from protein binding sites is not usually a problem.
How do you withdraw an anti-epileptic drug?
Avoid abrupt withdrawal especially in barbituates and benzodiazepines.
In the case of barbituates it can take months. (primidone, phenobarbital)
How long can you not drive for if you have one single isolated seizure?
6 months
How long must a patient be seizure free for or established pattern so they can drive again?
1 year
If the patient has had seizures whilst being awake but now only has them when they are asleep, how long must this happen for so they can drive again?
Establish the pattern for 3 years
How long can a patient not drive for if they have a medication change or withdrawal?
6 months
if a patient has a seizure whilst their medication has changed or withdrawn, how long must they go without driving?
1 year (if medication restarted and they remain seizure free it may be considered after 6 months)
What are the first and second line anti-epileptics for focual seizures?
First line: Lamotrigine or Levetiracetam
Second line: Carbamazepine, Oxcarbazepine, Zonisamide
Got to take 2 L’s to get you focused COZ
Whats the first and second line for tonic clonic seizures
1st: Sodium Valproate
2nd: Lamotrigine or Levetiracetam
Whats the first and second line for absence seizures
1st: Ethosuximide
2nd: Sodium Valproate
Whats the first and second line for absence and another seizure
1st: Sodium valproate
2nd: Lamotrigine or Levetiracetam
Whats the first and second line for myoclonic seizures
1st: sodium valproate
2nd: Levetiracetam
Whats the first and second line for Atonic seziures
1st: sodium valproate
2nd: Lamotrigine
Whats the first and second line for tonic seizures
1st: sodium valproate
2nd Lamotrigine
What other two anti-epileptics can be used in tonic seizures?
Carbamazepine and Vigabatrin
Whats the definition of Status epilepticus
A seizure lasting for longer than 5 minues
Whats the different treatment options for Status epilepticus depending on where you are?
In the community: Buccal Midazolam 10mg or Rectal diazepam 10-20mg
If resus facilities available: IV lorazepam 4mg
if the seizure doesn’t stop within 5-10 minutes then give another dose
What do you give if the status epilepticus seizure fails to respond after 2 benzodiazepine doses?
Give Levetiracetam, Phenytoin, Sodium valproate
What do you do if the status epilepticus fails to respond to the benzodiazepines and the anti-epileptics?
Give Phenobarbital or General anaesthesia
What are the drug interactions for Carbemazepine?
Drugs that cause hepatotoxicity: Amiodarone, Itraconazole, Macrolides, Alcohol
It’s an enzyme inducer
Drugs that lower seizure threshold e.g. Tramadol, Theophylline, Quinolones
Drugs that cause hyponatraemia e.g. SSRI’s, diuretics
DOAC’s
Oral contraceptives
What are the drug interactions for Phenytoin?
Drugs that cause hepatotoxicity: Amiodarone, Itraconazole, Macrolides, Alcohol
It’s an enzyme inducer
Drugs that lower seizure threshold e.g. Tramadol, Theophylline, Quinolones
Anti-folates e.g. Methotrexate, Trimethoprim
doac, carbamazepine, oral contraceptive pill, ulipristal.
What are the drug interactions for Sodium Valproate ?
Drugs that cause hepatotoxicity: Amiodarone, Itraconazole, Macrolides, Alcohol
It’s an enzyme inhibitor
Drugs that lower seizure threshold e.g. Tramadol, Theophylline, Quinolones
What effect does phenobarbital have on CYP enzymes?
It’s an inducer
Side effects of Carbamzepine
Depression and suicide
Hepatotoxicity
Hypersensitivity
Blood dyscrasias
Vit D deficiency- bone pain
Hyponatraemia
Oedema
Nausea vomiting sedation dizziness and ataxia are dose related and are most common at the start of treatment
Hyponatraemia, eucopenia and thrombocytopenia are very common.
carbamazepine known to be an enzyme inducer and induces its down metabolism
Side effects of Phenytoin
Depression and suicide
Hepatotoxicity
Hypersensitivity
Blood dyscrasias
Vit D deficiency- bone pain
Coarsening appearance and facial hair
Gingival hyperplasia, agranulocytosis, thrombocytopenia, altered taste
Side effects for Sodium Valproate
Depression and suicide
Hepatotoxicity
Hypersensitivity
Blood dyscrasias
Vit D deficiency- bone pain
Pancreatities
Teratogenicity
How long can a hypersensitivity reaction take to develop?
8 weeks
What are the symptoms of a hypersensitivity reaction?
Abdominal pain
Jaundice
Dark urine
Rash
LIVER, RASH, FEVER, SOB then Multi organ failure
What anti-epileptics cause hypersensitivity reactions
carbamzepine
phenobarbital
phenytoin
primidone
lamotrigine
Lacosamide
Rufinamide
Oxecarbazepine
CP3L2RO
What anti-epileptics cause skin rash
Lamotrigine- steven johnson syndrom
What anti-epileptics cause Bloody dyscrasias
Carbamazepine, Valproate, Ethosuximide, Topiramzte, Phenytoin, Lamotrigine, Zonisamide
C VET PLZ
What anti-epileptics cause eye disorders
Vigabatrin (reduced visual field)
Topiramate (secondary glaucome)
What anti-epileptics cause Encephalopathy
Vigabatrin
What anti-epileptics cause respiratory depression
Gabapentin and Pregabalin
What’s carbamazepine’s therapeutic range?
4-12 mg/L
Whats the signs of carbamazepine toxicity?
HANDBAG
Hyponatraemia, Ataxia, nystagmus, Drowsiness, Blurred vision, Arrhythmias, GI disturbances
Whats the therapeutic range of phenytoin?
10-20 mg/L
Whats the signs of Phenytoin toxicity?
SNACHD
Slurred speech, Nystagmus, Ataxia, Confusion, Hyperglycaemia, Double vision
Key points of anti-epileptics during pregnancy
The risks of harm to mother and baby from a convulsive seizure outweighs the risk of continued therapy.
Folic acid can reduce the risk of neural tube defects
Vit K injection administered at brith to minimise risk of neonatal haemorrhage
Most risk: Sodium valproate
Topiramate can cause cleft palate
Key points of anti-epileptics and breastfeeding
Encouraged to breastfeed
High presence in milk: Primidone, Ethosuximide, Lamotrigine, Zonisamide
Risk of drowsiness: Primidone, Phenobarbital, Benzydiazepines
Withdrawal effects: Phenobarbital, primidone, Benzodiazepines and lamotrigine
Enzyme inducing anti-epileptics:
Carbamazepine
Oxcarbazepine
Phenobarbital
Phenytoin/Fosphenytoin
Primidone
Topiramate
Definition of an absence seizure
Abrupt loss of awareness for a short period
Definition of a myoclonic seizure
Seizure involving a group of muscles causing jerking motions
Definition of a tonic clonic seizure
Seizures involving stiffening (tonic) or sudden relaxation (atonic) of muscles
Definition of focal seizures
Start in one part of the brain and affect the corresponding side of the body
What are the MHRA warnings for carbamazepine?
Prescribe a specific brand
Risk of suicidal thoughts
Risk of congenital malformations in pregnancy
Risk of steven johnsons syndrome in presence of certain allele that can be found in chinese or thai origin - should always test patients from malaysia and phillipines.
Key points of phenytoin
Narrow therapeutic index drug and follows non linear kinetics. Small change in dose can result in a large change in blood levels.
Drug monitoring in patients with epilepsy is not routinely performed.
Anti-folate
What is the optimum plasma levels for phenobarbital?
15-40mg/L
Patient and carer advice for phenobarbital?
28 days to collect prescription from the date prescribed
Consider vitamin D supplementation for immobilised patients or those who have inadequate sun exposure or dietary intake of calcium
What is the % risk of someone on sodium valproate having teratogenicity?
30-40%
What teratogenicity can topiramate cause?
Neurodevelopmental disabilities
Cleft lip
What are the two benzodiazepines licensed in epilepsy?
Clonazepam and Clobazam
What type of seizure can lamotrigine exacerbate?
Myoclonic
What drugs exacerbate generalised seizures?
Carbamazepine, Pregabalin, Gabapentin
What other indications is carbamazepine licensed for?
Trigeminal neuralgia
Bipolar if unresponsive to lithium
Diabetic neuropathy
Alcohol withdrawal
