EPILEPSY Flashcards
Which epileptics can be given once daily at bedtime ?
Lamotrigine, perampanel, phenobarbital, and phenytoin, which have long half-lives, can be given once daily at bedtime
Category 1 epileptic drugs that must be maintained on the same brand when dispensing ?
Carbamazepine, phenobarbital, phenytoin, primidone.
Category 2 epileptic drugs?
Clobazam, clonazepam, eslicarbazepine acetate, lamotrigine, oxcarbazepine, perampanel, rufinamide, topiramate, valproate, zonisamide. For these drugs, the need for continued supply of a particular manufacturer’s product should be based on clinical judgement and consultation with the patient
Category 3 epileptic drugs ?
Brivaracetam, ethosuximide, gabapentin, lacosamide, levetiracetam, pregabalin, tiagabine, vigabatrin. For these drugs, it is usually unnecessary to ensure that patients are maintained on a specific manufacturer’s product
Which drugs have a risk of anti epileptic hypersensitivity syndrome ?
carbamazepine, lacosamide, lamotrigine, oxcarbazepine, phenobarbital, phenytoin, primidone, and rufinamide); rarely cross-sensitivity occurs between some of these antiepileptic drugs
what are the symptoms of Antiepileptic hypersensitivity syndrome ?
The symptoms usually start between 1 and 8 weeks of exposure; fever, rash, and lymphadenopathy are most commonly seen.
Other systemic signs include liver dysfunction, haematological, renal, and pulmonary abnormalities, vasculitis, and multi-organ failure.
The MHRA has advised (August 2008) that all antiepileptic drugs are associated with a small increased risk of …… ?
suicidal thoughts and behaviour. Symptoms may occur as early as one week after starting treatment.
why should abrupt withdrawal of benzodiazepines and barbiturates should be avoided ?
can precipitate severe rebound seizures.
In patients receiving several antiepileptic drugs, only one drug should be withdrawn at a time.
Patients who have had a first unprovoked epileptic seizure or a single isolated seizure must not drive for how long ?
6 months
Patients with established epilepsy may drive a motor vehicle provided they are not a danger to the public and are compliant with treatment and follow up. To continue driving, these patients must be seizure-free for how long ?
at least one year (or have a pattern of seizures established for one year where there is no influence on their level of consciousness or the ability to act); also, they must not have a history of unprovoked seizures.
Patients who have had a seizure while asleep are not permitted to drive for how long ?
for one year from the date of each seizure, unless:
a history or pattern of sleep seizures occurring only ever while asleep has been established over the course of at least one year from the date of the first sleep seizure; or
an established pattern of purely asleep seizures can be demonstrated over the course of three years if the patient has previously had seizures whilst awake (or awake and asleep).
What is DVLA recommendation when about medication changes and withdrawal?
The DVLA recommends that patients should not drive during medication changes or withdrawal of antiepileptic drugs, and for 6 months after their last dose.
What is a first line and second line treatment for focal (partial ) seizures with or without secondary generalisation ?
first line lamotrigine or carbamazepine
Alternative=levitaracetam, valrpoate, oxcarbazepine
First line treatment for tonic clonic seizures ?
first line: valproate or carbamazepine.
Alternative is lamotrigine
First line treatment for absence seizures ?
Ethosuximide is first line. However, valproate if high risk of generalised tonic clonic seizure. Alternative is lamotrigine
First line for myoclonic seizures ?
Valproate is first line, however alternatives are topiramate, levetiracetam
First line for atonic/tonic seizures?
valproate
Which anti epileptic has the highest risk of teratogenicity ?
valproate/ valproic acid
Which anti epileptic may cause cleft palate when use in first trimester of pregnancy ?
topiramate
Carbamazepine + contraception =?
reduced efficacy of contraceptives
Feotal growth should be monitored when patient is taking which anti epileptic drugs ?
topiramate/levetiracetam
In women taking anti epileptic drugs what dose of folic acid they should take and how ?
5 mg taken before conception and until week 12 of pregnancy
Women who are breastfeeding and taking anti epileptics, what are the monitoring requirements for their baby ?
monitor drowsiness, weight gain, feeding difficulty, adverse effect, developmental milestone
Which anti epileptics are present in milk in high amounts ?
zosinamide, ethosuximide, lamotrigine and primidone
Which anti epileptics accumulate in infant due to slower metabolism ?
phenobarbital, lamotrigine
Which anti epileptics inhibit sucking reflex ?
phenobarbital and primidone
With which anti epileptic drugs abrupt withdrawal of breast-feeding especially should be avoided ?
phenobarbital/primidone
What factors would predispose to higher risk of developing skin rashes while on lamotrigine ?
High initial dose, rapid dose increase, if lamotrigine is given with valproate ( valproate is enzyme inhibitor )
Which anti epileptic drugs may cause blood dyscrasias?
ethosuximide, valrpoate, carbamazepine, phenytoin, lamotrigine, topiramate, zonisamide.
Patients should report signs of infection, bruising or bleeding
Which anti epileptic may cause visual field defects ?
vigabatrin. patients should report new visual symptoms
Which anti epileptic may cause acute myopia with secondary angle-closure glaucoma and therefore patients should be advised to report sings of raised intra-ocular pressure ?
Topiramate
With which anti epileptic encephalopathic symptoms may occur and what action should be taken ?
vigabatrin , withdraw or reduce dose. Encephalopathic symptoms: marked sedation, stupor and confusion with non-specific slow wave EEG.
MOA of phenytoin ?
binds to neuronal sodium channels in their inactive state: prolongs inactivity
Phenytoin indications ?
focal seizures and generalised tonic clonic seizures
Which seizures does phenytoin exacerbates and thus should be avoided ?
absence and myoclonic seizures
What is phenytoin therapeutic range ?
10-20mg/l
In which patient groups protein binding would be reduced, thus potentially increasing phenytoin toxicity ?
pregnancy, children, elderly and liver failure
what are the signs and symptoms phenytoin toxicity ?
- slurred speech
- nystagmus
- ataxia
- confusion
- hyperglycaemia
- diplopia/blurred vision
Phenytoin (antifolate ) side effects ?
- Change in appearance= coarsening of facia features, acne, hirsutism, gingival hyperthropy.
- Blood dyscrasias= leucopenia that is severe requires withdrawal.
- Antiepileptic hypersensitivity syndrome
- Rashes , rarely SJS
Which patient groups have increased risk of SJS and require screening before treatment ?
Han Chinese and Thai patients with HLA-B*1502 allele
Phenytoin patients counselling ?
Report signs of infections=fever, sore throat, mouth ulcers, or unexplained bruising or bleeding ( blood dyscrasias )
Report fever, rash, swollen lymph nodes ( anti epileptic hypersensitivity syndrome )
Report signs of liver toxicity: dark urine, nausea and vomiting, abdominal pain, itching, jaundice
How does phenytoin affects vitamin D levels ?
phenytoin induces vitamin D metabolism
Monitoring requirements for phenytoin ?
serum vitamin D, liver function
Side effects of IV phenytoin ?
BRADYCARDIA, HYPOTENSION
Arrythmias, cardiovascular collapse, reparatory arrest
What could happen if phenytoin IV administered too rapid ?
CVS/CNS depression
If during IV phenytoin administration bradycardia or hypotension occurs, what should be done ?
reduce administration rate
What monitoring should be in place for IV phenytoin ?
ECG/BP
Side effects of fosphenytoin IV ?
Accosciated with severe cardiovascular reactions; Asystole ventricular fibrilation cardiac arrest heart block hypotension bradycardia
Why could potentially fosphenytoin IV be preferred over phenytoin IV ?
fosphenytoin has less infection site reactions and can be given more rapidly with IV
IV fosphenytoin monitoring ?
heart rate, BP, respiratory function during infusion and observe patient for at least 30 minutes after
Which drugs given with phenytoin can potentially lead to phenytoin toxicity ?
amiodarone, cimetidine, miconazole, fluconazole, chloramphenicol, metronidazole, clarithromycin, fluoxetine, sertraline, diltiazem, valproate, trimethoprim
Trimethroprim + phenytoin = interaction?
Increased anti folate effects that may lead to blood dyscrasias + increased phenytoin interactions
Which drugs would reduce phenytoin concentrations and result in therapeutic failure ?
St Johns wort, rifampicin
Which drugs would antagonise anticonvulsant effects of phenytoin?
quinolones, tramadol, mefloquine, SSRIs, antipsychotics, TCA all lower seizure threshold
Which drugs given with phenytoin would lead to increased risk of blood dyscrasias?
methotrexate, trimethoprim
Phenytoin is enzyme inducer, therefore which drugs concentration would phenytoin reduce?
Hormoanl contraceptives/HRT reduced efficacy
Warfarin ( reduces anticoagulant effect )
Cotricosteroids
Levothryoxine ( increased risk of hypothyroidism )
Liothyronine
MOA of carbamazepine ?
inhibits neuronal sodium channels, stabilises membrane potential and reduces neuronal excitability
In which types of seizures carbamazepine is a first line treatment ?
Focal seizures and generalised tonic clonic seizures
Which seizures carbamazepine may exacerbate and thus should be avoided ?
atonic, clonic and myoclonic seizures
Carbamazepine therapeutic range ?
4-12 mg/L
When should carbamazepine plasma concentrations should measured ?
after one to two weeks
What are the signs and symptoms of carbamazepine toxicity ?
Incordination Hyponatraemia Ataxia Nystagmus Drowsiness Blurred vision and diplopia Arrythmias Nausea, vomiting, diarrhoea
Carbamazepine side effects ?
Hyponatraemia Leucopenia, thrombocytopenia Hepatoxicity Antiepileptic hypersensitivity syndrome SJS ( increased risk if given with phenytoin )
What side effects of carbamazepine are common in the beginning of the treatment and. in the elderly ? How can these side effects be minimised ?
Headache, ataxia, drowsiness, nausea, vomiting, blurred vision, unsteadiness, allergic skin reactions
MR preparations may help to reduce the risk of side effects
Which drugs can lead to increased concentrations of carbamazepine ?
cimetidine, macrolides, fluoxetine, miconazole
Which drugs can decrease carbamazepine concentrations ?
St Johns wort, phenytoin
Which drugs given with carbamazepine may lead to increased risk of hyponatraemia ?
aldosterone antagonists, SSRIs, TCA’s, diuretics, NSAIDs,
Which drugs given with carbamazepine may lead to increased risk of hepatoxicity ?
tetracyclines, sulfasalazine, sodium valproate, methotrexate, isoniazid, statins, fluconazole, alcohol
Sodium valproate mechanism of action ?
Weak inhibitor of neuronal sodium channels, stabilises, resting membrane potential and reduces neuronal excitability.
Sodium valproate is first line treatment in what type of seizures ?
First line treatment in all types of generalised seizures
What are the side effects of sodium valproate ?
hepatoxicity, blood dyscrasias, pancreatitis
Patient is on sodium valproate and they have abnormally prolonged prothrombin time, what action should be taken ?
discontinue
How patient should be counselled if they are taking sodium valproate ?
Must report signs of liver toxicity: persistent vomiting, abdominal pain, jaundice, malaise, drowsiness
Must report signs of infection: fever, sore throat, mouth ulcers, bruising or bleeding
Must report signs of pancreatitis: abdominal pain, nausea or vomiting
Sodium valproate monitoring requirements ?
Monitor liver function before therapy and during first 6 months especially in patients most at risk.
Measure full blood count and ensure no undue potential for bleeding before starting and before surgery.
STATUS EPILEPTICUS : Seizures lasting longer than 5 minutes should be treated urgently with ??
IV lorazepam (repeated once after 10 minutes if seizures recur or fail to respond).
Intravenous diazepam is effective FOR STATUS EPILEPTICUS but it carries a high risk OF WHAT ?
thrombophlebitis (reduced by using an emulsion formulation)
How should non-convulsive status epilepticus should be treated ?
If there is incomplete loss of awareness, usual oral antiepileptic therapy should be continued or restarted.
How should febrile convulsions should be treated ?
Brief febrile convulsions need no specific treatment; antipyretic medication (e.g. paracetamol), is commonly used to reduce fever and prevent further convulsions
