Epilepsy And Seizure Disorders Flashcards
What is epilepsy?
A sudden surge of electrical activity of neurones in the brain
What are non-epileptic seizures?
Unrelated to abnormal electrical activity in the brain
Organic
Psychogenic
What are the drugs used to treat seizures?
Barbiturates - phenobarbital (ON), primidone, thiopental Benzodiazepines Carbamazepine Ethosuximide Gabapentin, pregabalin Lacosamide Lamotrigine (ON) Levetiracetam Phenytoin (ON) Sodium valproate Topiramate Zonisamide
What is the first line treatment for focal seizures with/without secondary generalisation?
Lamotrigine or carbamazepine
What is the second line treatment for focal seizures with/without secondary generalisation?
Levetiracetam
Valproate
Oxcarbazepine
What is the first line treatment for tonic clonic seizures?
Valproate
Carbamazepine
What is the second line treatment for tonic clonic seizures?
Lamotrigine
What is the first line treatment for absence seizures?
Ethosuximide or valproate
What is the second line treatment for absence seizures?
Lamotrigine
What is the first line treatment for myoclonic seizures?
Valproate
What is the second line treatment for myoclonic seizures?
Topiramate
Levetiracetam
What is the first line treatment for atonic/tonic seizures?
Valproate
What seizures use lamotrigine as first line?
Focal seizures
Tonic clonic
What seizures use carbamazepine as first line?
Focal
Tonic clonic
What seizures use levetiracetam as second line?
Focal
Myoclonic
What seizures use valproate as second line?
Focal
What seizures use valproate as first line?
Tonic clonic
Absence
Myoclonic
Atonic/tonic
What seizures use oxcarbazepine as second line?
Focal
What seizures use ethosuximide as first line?
Absence
What seizures use topiramate as second line?
Topiramate
What is the MHRA warning for epilepsy?
Antiepileptic drugs - new advice on potential harm when switching between different manufacturer products for a particular drug in the treatment of epilepsy
What are the category one antiepileptics?
Carbamazepine
Phenytoin
Phenobarbital
Primidone
Maintain on same product
What are the category two antiepileptics?
Valproate
Lamotrigine
Clonazepam
Topiramate
Clinical judgement and patient consultation
What are category three antiepileptics?
Levetiracetam
Gabapentin
Pregabalin
Ethosuximide
Do not need to maintain on same product
How do you withdraw epilepsy treatment?
Gradually reduce dose under specialist supervision
Avoid abrupt withdrawal - can precipitate severe rebound seizures
Withdraw one epileptic drug at a time
Do you need to inform DVLA of epilepsy?
Yes, can drive car but not passenger carrying vehicle
How long do you need to be seizure free for in order to be able to drive?
1 year
When is there a driving ban in people with epilepsy?
During medication changes or withdrawal
6 months after last dose
6 months for first unprovoked epileptic seizure
Which antiepileptics have an increased risk of teratogenicity?
Valproate/valproate acid - highest risk
Carbamazepine, phenytoin, phenobarbital, primidone, lamotrigine - increased risk
Topiramate in first trimester - cleft palate
What do you have to be cautious with contraception and antiepileptics?
Enzyme inducing e.g. carbamazepine reduce efficacy of hormonal contraception
Which antiepileptics need dose adjustments in pregnancy?
Phenytoin
Carbamazepine
Lamotrigine
Which antiepileptics need foetal growth monitoring?
Topiramate
Levetiracetam
What needs to be taken before conception and until week 12 of pregnancy if taking antiepileptics?
5mg folic acid daily to reduce risk of neural tube defects
Which antiepileptics cause withdrawal effects in newborns?
Benzodiazepines and phenobarbital
What do you need to monitor if taking antiepileptics me breastfeeding?
Drowsiness
Weight gain
Feeding difficulty
Developmental milestones
Which antiepileptics are present in high amounts in milk?
Zonisamide
Ethosuximide
Lamotrigine
Primidone
Which antiepileptics accumulate due to a slower metabolism in infant?
Phenobarbital
Lamotrigine
Which antiepileptics inhibit the sucking reflex?
Phenobarbital
Primidone
Which antiepileptics have an established risk of drowsiness in babies?
Benzodiazepines
Phenobarbital
Primidone
Which antiepileptics have a higher risk of withdrawal when breastfeeding?
Phenobarbital
Primidone
What are the side effects of antiepileptics?
Antiepileptic hypersensitivity syndrome Risk of suicidal behaviour and thoughts Skin rashes Blood dyscrasias Eye problems Encephalopathic symptoms
What are the symptoms associated with anti epileptic hypersensitivity syndrome?
Rash
Fever
Lymphadenopathy
Systemic involvement
Discontinue immediately
What antiepileptics are associated with hypersensitivity syndrome?
Carbamazepine Phenytoin Phenobarbital Primidone Lamotrigine
What are the MHRA warnings for antiepileptics?
Small increased risk of suicidal behaviour and thoughts
Gabapentin risk of severe respiratory depression
What are the counselling points for antiepileptics?
Report any mood changes, distressing thoughts or feelings about suicide or self harm
Report signs of infection, bruising or bleeding
Report new visual symptoms
Report signs of raised intraocular pressure
What antiepileptics have a high risk of skin rashes?
Lamotrigine
Valproate
What antiepileptics have a risk of blood dyscrasias?
Ethosuximide Valproate Carbamazepine Phenytoin Lamotrigine Topiramate Zonisamide
Which antiepileptic causes visual field defects?
Vigabatrin
Topiramate
Which antiepileptics cause encephalopathic symptoms?
Vigabatrin
What antiepileptics are enzyme inhibitors and cause an increased plasma concentration?
Sodium valproate
What antiepileptics are enzyme inducers and cause a decreased plasma concentration?
Carbamazepine
Phenytoin
Phenobarbital
Interact with oral contraceptives and warfarin
What is the mechanism of action of phenytoin?
Binds to neuronal sodium channels in their inactive state, prolongs inactivity
What is phenytoin used for?
Focal seizures and generalised tonic clonic seizures
Exacerbates absence and myoclonic seizures
That is the therapeutic range of phenytoin?
10-20mg/L
40-80 micromol/L
What are the monitoring requirements for phenytoin?
Small changes in dose = large changes in plasma concentration
When protein binding is reduced, monitor the plasma free drug concentration
Why are the signs and symptoms of toxicity of phenytoin?
Snatched
Slurred speech Nystagmus Ataxia Confusion Hyperglycaemia Diplopia, blurred vision
What is the equivalent dose conversions of phenytoin sodium to phenytoin base?
100mg phenytoin sodium = 92 mg phenytoin base
What are the side effects of phenytoin?
Change in appearance Blood dyscrasias Hypersensitivity Rashes Low vitamin D = osteomalacia and rickets Hepatotoxicity Suicidal ideation Bradycardia Hypotension CV reactions
What are the counselling points for phenytoin side effects?
Report signs of infection
Report fever, rash, swollen, lymph nodes
Report signs of liver toxicity
What are the NHS improvement patient safety alerts for phenytoin?
Risk of death and severe harm from error with injectable phenytoin
What is the equivalent dose of fosphenytoin to phenytoin sodium?
Fosphenytoin 1.5mg = phenytoin sodium 1mg
What are the interactions that increase phenytoin concentration and therefore toxicity?
Amiodarone Cimetidine Miconazole Fluconazole Chloramphenicol Metronidazole Clarithromycin Fluoxetine Sertraline Diltiazem Valproate Trimethoprim
What are the interactions that decrease phenytoin concentration?
St. John’s wort
Rifampicin
What interactions antagonise the anticonvulsant effect of phenytoin?
Quinolones Tramadol Mefloquine SSRIs Antipsychotics TCA
What interactions increase the antifolate effect of phenytoin and therefore increase the risk of blood dyscrasias?
Methotrexate
Trimethoprim
Phenytoin is an enzyme inducer and reduces the concentration of which drugs?
Hormonal contraceptives Warfarin Corticosteroids Levothyroxine Liothyronine
What is the mechanism of action of carbamazepine?
Inhibits neuronal sodium channels
Stabilises membrane potential and reduces neuronal excitability
When is carbamazepine used?
First line in focal seizures, generalised tonic clonic seizure
Exacerbates atonic, clonic and myoclonic seizure
What is the therapeutic range of carbamazepine?
4-12mg/L or 20-50 micromol/L
Measures after 1-2 weeks
What are the signs and symptoms of carbamazepine toxicity?
I handbag
In coordination Hyponatraemia Ataxia Nystagmus Drowsiness Blurred vision and diplopia Arrhythmias GI disturbance
What are the side effects of carbamazepine?
Blood dyscrasias Hepatotoxicity Hypersensitivity reactions Rashes Hyponatraemia
What are the counselling points of carbamazepine side effects?
Signs of infection
Signs of liver toxicity
Fever, rash, lymphadenopathy
Who are at risk of SJS with carbamazepine use?
Han Chinese and Thai patients with allele
What are the monitoring requirements for carbamazepine?
Plasma concentration
FBC
LFT
Which side effects of carbamazepine are dose related and dose limiting?
Headache Ataxia Drowsiness Nausea Vomiting Blurred vision Unsteadiness Allergic skin reactions
MR reduce risk of side effects
What are the interactions that increase carbamazepine toxicity?
Cimetidine
Macrolides
Fluoxetine
Miconazole
What interactions with carbamazepine decrease the concentration?
St Johns Wort
Phenytoin
What interactions with carbamazepine antagonise the anticonvulsant effects?
Quinolones Mefloquine SSRI Antipsychotics TCA
What interactions with carbamazepine increase the risk of hyponatraemia?
Aldosterone antagonists SSRIs TCAs Diuretics NSAIDs
What carbamazepine interactions increase the risk of hepatotoxicity?
Tetracyclines Sulfasalazine Sodium valproate Methotrexate Isoniazid Statins Fluconazole Alcohol
Carbamazepine is an enzyme inducer, which drugs does it reduce the concentration of?
Warfarin
Hormonal contraceptives
What is the mechanism of action of sodium valproate?
Weak inhibitor or neuronal sodium channels
Stabilises resting membrane potential and reduces neuronal excitability
When is sodium valproate used?
First line in all types of generalised seizures
What is the MHRA warnings for sodium valproate?
Valproate medicines are contraindicated in women and girls of childbearing potential unless in PPP and only if no other alternatives
Contraindicated in pregnant women for bipolar disorder and only considered in epilepsy if no other alternative
Consult GP immediately if pregnant/planning pregnancy
Who is the PPP for?
For all women of child bearing potential under specialist supervision
What contraceptives do the PPP need to use!
User independent methods
User dependent methods - 2+ e.g. COC + barrier method + pregnancy test
What are the side effects of sodium valproate?
Hepatotoxicity
Blood dyscrasias
Pancreatitis
What are the side effect counselling points for valproate?
Report signs of liver toxicity
Report signs of infections
Report signs of pancreatitis
What interactions with sodium valproate antagonise the anticonvulsant effects?
Quinolones Mefloquine SSRIs Antipsychotics TCA
What interactions with sodium valproate increase the risk of hepatotoxicity?
Statins Carbamazepine Tetracyclines Fluconazole Isoniazid Itraconazole Methotrexate Sulfasalazine
As valproate is an enzyme inhibitor, it increases the drug concentration of what drugs?
Other anti epileptics
What is status epilepticus?
Epileptic fits follow one after the other without regaining consciousness
What do you give for convulsive status epilepticus?
IV lorazepam
Avoid diazepam as it causes thrombophlebitis
What do you give for incomplete loss of awareness for non-convulsive status epilepticus?
Continue or restart usual oral antiepileptic drug
What do you give for complete loss of awareness for non-convulsive status epilepticus?
IV Lorazepam
What do you give for febrile convulsions?
Paracetamol
If > 5 mins then IV lorazepam
What do you give for convulsive seizures or febrile seizures > 5 mins in the community?
Diazepam rectal solution
Midazolam oromucosal solution
Repeat once after 10-15 mins if necessary
