Nervous system Flashcards
What is a side effect associated with ALL epilepsy drugs?
Increased risk of suicidal thoughts and behaviours
Patients should seek medical advice if they develop mood changes/distressing thoughts etc
How long must established epileptic patients be seizure-free for before they can drive?
1 year
When are epilepsy sufferers banned from driving?
- During medication changes
- 6 months after last dose if stopping medication
- 6 months if single isolate seizure/first unprovoked seizure
If an epileptic patient has a seizure due to withdrawal of treatment, how long are they banned from driving for?
1 year
Relicensing may be considered earlier if treatment is reinstated and no seizures for 6 months
For which type of seziure is sodium valproate NOT a recommended first line treatment?
Focal seizures
First line treatment for focal seizures?
Carbamazepine or lamotrigine
First line treatment for tonic-clonic seizures?
Sodium valproate/carbamazepine
- lamotigine if SV not appropriate
First line treatment for absence seizures?
Sodium valproate / ethosuximide
- alternative = lamotrigine
First line treatment for myoclonic seizures?
Sodium valproate
alternative - topiramate or levetiracetam
In which type of generalised seizure is lamotrigine not recommended as an alternative first line therapy to sodium valproate in pre-menopausal women?
Myclonic seizures
recommended alternatives are topiramate or levetiracetam
Which are category 1 anti-epileptics that should always be maintained on the same product/brand?
Phenytoin, carbamazepine, phenobarbital, primidone
Which anti-epileptic has the HIGHEST risk of teratogenicity?
Sodium valproate
Which anti-epileptic has a risk of causing cleft palate if it is used in the first trimester?
Topiramate
What supplements should pregnant women on anti-epileptics take to reduce the risk of neural tube defects?
Folic acid 5mg until week 12
What treatment should be given to neonates at birth if their mothers have been taking anti-epileptics in pregnancy?
Vitamin K to reduce risk of neonatal haemorrhage
How should anti-epileptics be withdrawn?
- Gradually
- withdraw one anti-epileptic at a time
‘In the treatment of epilepsy monotherapy should be prescribed wherever possible, particularly in pregnancy or breastfeeding’
True or false?
TRUE
Can women taking anti-epileptics breast feed?
Yes if on monotherapy.
Monitor infants for sedation, feeding difficulties, weight gain and developmental milestones
Which anti-epileptics might affect foetal growth?
Topiramate and levetiracetam
Which anti-epileptics are associated with blood dyscrasias and require patients to report any bruising, bleeding or signs of infection?
Carbamazepine Valproate Ethosuximide Topiramate Phenytoin Lamotrigine Zonisamide
C Vet Plz
Which anti-epileptic is an enzyme inducer that may reduce efficacy of hormonal contraception?
Carbamazepine
What is the maximum dose of Gabapentin when used to treat neuropathic pain?
3.6g /day
Which anti-epileptic is also effective in migraine prophylaxis?
Gabapentin (this is an unlicensed use)
Which anti-epileptic is associated with the risk of serious skin reactions including Steven-Johnson syndrome?
Lamotrigine
Most rashes occur within first 8 weeks
Higher risk if high initial dose, rapid dose increase or used with valproate
Which anti-epileptic can be associated with severe respiratory depression even without opioids?
Gabapentin
Which anti-epileptics are enzyme inducers?
Carbamazepine, phenytoin + phenobarbital
What is the therapeutic range of phenytoin?
10-20 mg/L or 40-80 micromol/L
When should plasma levels of phenytoin be taken?
After 10 days (trough level - pre dose)
What are the signs of phenytoin toxicity?
Nystagmus (uncontrolled/involuntary eye movements), slurred speech, ataxia, confusion, hyperglycaemia
What is the risk if phenytoin is administered too quickly?
Risk of bradycardia and hypotension - C/I in heart block
Max infusion rate 50mg/min
Which anti-epileptic is also licensed for generalised anxiety disorder?
Pregabalin
What is the maximum dose of Pregabalin when used to treat neuropathic pain?
600mg / day
100mg phenytoin sodium is equivalent to how much phenytoin base?
92mg
Which anti-epileptic is an enzyme inhibitor?
Sodium valproate
What is the therapeutic range for carbamazepine?
4-12 mg/L
What are the signs of carbamazepine toxicity?
Vomiting, arrythmias, visual disturbances, incoordination, hyponatraemia, ataxia
What are the signs of anti-epileptic hypersensitivity syndrome?
Fever, rash, lympadenopathy - potentially fatal
What is a potential visual side effect of topiramate?
Acute myopia (short-sightedness) with secondary angle glaucoma
- usually occurs after a month of treatment
- seek specialist advice and discontinue as fast as possible if raised intra-ocular pressure
What is a potential visual side effect of vigabatrin?
Visual field defects
- can persist despite discontinuation
- new visual symptoms should be referred
Which anti-epileptic is associated with encephalopathic symptoms?
Vigabatrin
signs include sedation/stupor/confusion
MHRA advice with sodium valproate?
Contra-indicated in women and girls off child bearing potential unless conditions of the pregnancy prevention programme are met and only if other treatments are ineffective/not tolerated
What is the risk of teratogenicity with valproate?
Neurodevelopmental disorders (30-40%) Congenital malformations (11%)
Other than epilepsy, what is valproate licensed for?
Migraine prophylaxis and bipolar disorder
What should pharmacists dispensing valproate do?
- Provide a patient card every time it is dispensed
- Remind patients of the risks in pregnancy and the need for annual specialist review
- Dispense in whole packs where available, always give PIL and warning sticker on box
What would you advise a woman taking valproate who had an unplanned pregnancy?
See their prescriber urgently and not stop treatment in the mean time
Is sodium valproate a black triangle drug?
Yes
What are some serious side effects of valproate?
- liver toxicity
- pancreatitis
- blood dyscrasias
What are the non-cognitive symptoms of dementia?
- psychiatric/behavioural problems (aggression)
- difficulties with daily activities
What are the cognitive symptoms of dementia?
- memory loss
- difficulty thinking
- problems with language
- problems with orientation
Which 3 acetylcholinesterase inhibitors are used to treat mild to moderate dementia due to Alzheimers disease?
- Donepezil
- Rivastigmine
- Galantamine
What are the side effects of rivastigmine?
- Hallucinations / sleep disorders
- GI disturbance (less likely with patch)
Which acetylcholinesterase inhibitor has a risk of neuroleptic malignancy syndrome?
Donepezil
Which drug is used to treat severe cognitive symptoms in dementia due to Alzheimers disease?
Memantine
Can also be used if acetlcholinesterases are C/I
‘Memantine is cautioned in epilepsy’
True or false?
True - can cause seizures
What are cholinergic side effects?
Diarrhoea Urination Muscle weakness/cramps Bronchospasm Emesis Lacrimation (teary eyes) Sweating
Which type of drugs are likely to cause cholinergic side effects?
Acetylcholinesterase inhibitors
Donepezil, rivastigmine, galantamine
- usually dose related, start low and titrate slow
How should convulsive seizures lasting >5 mins be treated in the community? (medical emergency)
EITHER Diazepam rectal solution
OR midazolam oromucosal solution
Which antidepressants cause mydriasis?
Tricyclic antidepressants eg, amitripyline
Mydriasis = dilation of the pupils
What schedule are most BZDs?
CD 4 part 1
Which BZDs are short acting?
Lorazepam + oxazepam
‘BZDs can cause a paradoxical increase in hostility and aggression’
True or false?
True - can be associated with behaviours such as talkativeness + excitement or aggression + antisocial behaviour
Signs of benzodiazepine overdose?
Ataxia, drowsiness, nystagmus, dysarthria, coma, respiratory depression
Why should BZDs be used with caution in renal impairment?
Chance of increased cerebral sensitivty to BZDs
How should BZDs be withdrawn?
- Gradually convert to an equivalent diazepam dose ON
- Reduce diazepam by 1-2mg/week
- Reduce in smaller steps at the end of withdrawal
What is the therapeutic index of lithium?
0.4-1 mmol/L
The lower end is suitable for prophylaxis/elderly
The higher end is used for acute manic episodes
How should lithium levels be taken?
Take 12 hours after dose
Should be taken 1 week after initiation, after any dose changes and every 3 months for maintenance
What are the signs of lithium toxicity?
N - Nervous system disturbance (confusion, drowsiness, incoordination, restlessness)
E - Extrapyrimidal symptoms (tremor, nystagmus, muscle weakness)
R - Renal disturbance (polyuria. incontinence, hypernatraemia)
V - Visual disturbance (blurred vision)
G - GI effects (diarrhoea and vomiting)
Can lithium be used in pregnancy?
No, risk of teratogenicity including cardiac abnormalities in the first trimester
What monitoring is required for patients on lithium?
- Bodyweight/BMI (can increase weight)
- eGFR (risk of renal impairment)
- Electorlytes (hyponatraemia can increase levels)
- FBC
- TFTs (risk of impaired thyroid func)
What adverse effects are associated with long term lithium use?
Thyroid disorders and mild cognitive and memory impairment
Contraindication for lithium?
Dehydration/low sodium diet - can increase lithium levels
Can lithium be given to epileptics?
Cautioned - can lower seizure threshold
Which drugs interact with lithium?
ACEi - reduce Li excretion
NSAIDs - reduce Li exretion
Diuretics - can cause hyponatraemia
Amiodarone - risk of arrythmias
Which SSRI is safe to use following MI/ in angina?
Sertraline
Why does St Johns Wort have many drug interactions?
It is an enzyme inducer
If patient stops taking this then the conc. of drugs can increase causing toxicity
