info about epileptic drugs Flashcards
what are some indications of carbamazepine?
focal seizures, tonic-clonic seizures, diabetic neuropathy, bipolar, alcohol withdrawal
which indications must you AVOID prescribing carbamazepine for? why?
all other generalised seizures that are not tonic-clonic eg absence myoclonic atonic&clonic
it will worsen them
what is the prescribing and dispensing info for carbamazepine when indicated for epilepsy?
stick to the same brand
what is the pt and carer advice for carbamazepine?
can cause hepatic, blood and skin disorders
report if u get symptoms of blood disorders [ulcer, bruising, fever, rash, bleeding]
what is the plasma concentration range of carbamazepine that will provide OPTIMUM results?
when should plasma conc be measured?
4-12mg/L
[20-50micromol/L]
measured after 1-2 weeks
what are the toxicity signs of carbamazepine?
HAND BAG
hyponatraemia
ataxia [affects balance and co-ordination]
nystagmus [involuntary movements of eyes]
drowsiness
blurred vision
arrhythmia
GI disorders
what is a serious side effect of lamotrigine and when does it normally occur?
serious skin reactions [esp in children]
serious skin rash: stevens-johnson syndrome
usually occurs in first 8 weeks
which anti-epileptic drug increases the plasma conc of lamotrigine
valproate
what is the pt and carer advice for lamotrigine?
withdraw if rash or hypersensitivity develops and see GP
report signs of blood disorder
what are the prescribing and dispensing information regarding phenytoin?
preparations are not bioequivalent. phenytoin sodium [injections/caps] not the same as phenytoin base [liquids]
prescribe same brand each time
what is the MHRA warning of phenytoin?
risk of suicide thoughts and behaviours [with all anti-epileptics]
risk of severe harm from error with injectable phenytoin
maintain pt on same brand
which route of administration should NOT be used with phenytoin?
iM route
use IV
which supplements should you consider [and for which types of patients] in those taking phenytoin?
vitamin D for those immobilised for long time or with inadequate sun exposure
what is the MHRA warning of phenytoin?
discontinue and report if signs of blood disorder develop
report if rash occurs
what is the target plasma concentration range for phenytoin?
10-20mg/L
40-80micromol/L
what are the toxicity signs of phenytoin? [5]
nystagmus slurred speech ataxia confusion HYPERglycaemia
what are the serious interactions with phenytoin? [8]
- miconazole: increases phenytoin toxicity
- amiodarone: increases conc of phenytoin
- DOACS: phenytoin decreases their exposure
- carbamazepine: phenytoin decreases its conc
- valproate: phenytoin decreases its conc
- CHC & progesterone: phenytoin decreases their efficacy
- ciclosporin: phenytoin decreases their conc
- bupropion and buspirone: phenytoin decreases their exposure
what are the side effects of PHENYTOIN?
PHENYTOIN
p- p45 inducer h - hirsutism [growth of hair on womans face/head] e - enlarged gums [gingival hyperplasia] ny - nystagmus/ataxia/vertigo etc t- teratogenic o- osteopenia i - interferes with folic acid n - neuropathy
what are the serious side effects that can occur with topiramate?
cleft palate
myopia [short sightedness] with secondary angle-closure glaucoma. report any visual issues. seek specialist if you get intra-ocular pressure
what should patients on ethosuximide report signs of/
bone marrow suppression
what must a prescription for clobazam be endorsed with?
endorsed with SLS
what is the MHRA warning of gabapentin?
risk of respiratory depression even without opioid drugs
adjust doses in pt with resp depression
what cd schedule is gabapentin in?
schedule 3
what must you observe pt taking gabapentin with and what is the advise that you must give them?
observe for signs of abuse/dependance
let them know that it can interact with alcohol and other drugs that cause CNS depression like opioids
what are the Important safety warnings regaring sodium valproate?
- risk of suicidal thoughts/behaviours [with all anti-epileptics]
- spontaneous adverse reactions when switching a pt between diff brands
- contraindicated in women with child bearing potential unless PPP is met
is sodium valproate an inhibitor or inducer and what does this mean?
inhibitor - increases conc of other drugs
which are stronger: inducers or inhibitors?
inducers
which types of patients should vitamin D supplementation be considered in and why?
pt who have been immobilised for long times or who have had inadequate sun exposure or reduced dietary intake of calcium
bc sodium valproate can reduce bone density, also correcting vitamin D deficiency reduces seizure risk
what are the side effects of sodium valproate?
valproate
valproate appetite increased [weight gain] liver failure pancreatitis and p45 inhibitor reversible hair loss oedema ataxia teratogenicity and tremor encephalopathy [brain damage]
what are the important interactions with sodium valproate? [6]
- lamotrigine: valproate increases its conc and can cause stevens johnson syndrome [more likely in chinese and thai]. monitor rash and adjust dose of lamotrigine
- phenytoin: phenytoin decreases conc of valproate and valproate increases conc of phenytoin
- pivmecillinam: increases risks of s/e
- topiramate: increases sodium valproate toxicity
- olanzapine: increases risk of s/e
- ertapenem, imipenem, meropenem: avoid. decreases conc of valproate
what is the pt and carer advice for sodium valproate?
- warn pt to report signs of blood, hepatic disorder and pancreatitis
- make sure women have a patient card and all important info like leaflets etc
what is vigabatrin indicated for?
focal seizures
what is the serious side effect of vigabatrin? what should patients report?
visual disturbances
report any visual symptoms asap
