info about epileptic drugs

Question 1

what are some indications of carbamazepine?

Answer 1

focal seizures, tonic-clonic seizures, diabetic neuropathy, bipolar, alcohol withdrawal

Question 2

which indications must you AVOID prescribing carbamazepine for? why?

Answer 2

all other generalised seizures that are not tonic-clonic
eg
absence
myoclonic
atonic&clonic

it will worsen them

Question 3

what is the prescribing and dispensing info for carbamazepine when indicated for epilepsy?

Answer 3

stick to the same brand

Question 4

what is the pt and carer advice for carbamazepine?

Answer 4

can cause hepatic, blood and skin disorders

report if u get symptoms of blood disorders [ulcer, bruising, fever, rash, bleeding]

Question 5

what is the plasma concentration range of carbamazepine that will provide OPTIMUM results?

when should plasma conc be measured?

Answer 5

4-12mg/L

[20-50micromol/L]

measured after 1-2 weeks

Question 6

what are the toxicity signs of carbamazepine?

Answer 6

HAND BAG

hyponatraemia
ataxia [affects balance and co-ordination]
nystagmus [involuntary movements of eyes]
drowsiness

blurred vision
arrhythmia
GI disorders

Question 7

what is a serious side effect of lamotrigine and when does it normally occur?

Answer 7

serious skin reactions [esp in children]
serious skin rash: stevens-johnson syndrome

usually occurs in first 8 weeks

Question 8

which anti-epileptic drug increases the plasma conc of lamotrigine

Answer 8

valproate

Question 9

what is the pt and carer advice for lamotrigine?

Answer 9

withdraw if rash or hypersensitivity develops and see GP

report signs of blood disorder

Question 10

what are the prescribing and dispensing information regarding phenytoin?

Answer 10

preparations are not bioequivalent. phenytoin sodium [injections/caps] not the same as phenytoin base [liquids]

prescribe same brand each time

Question 11

what is the MHRA warning of phenytoin?

Answer 11

risk of suicide thoughts and behaviours [with all anti-epileptics]
risk of severe harm from error with injectable phenytoin
maintain pt on same brand

Question 12

which route of administration should NOT be used with phenytoin?

Answer 12

iM route

use IV

Question 13

which supplements should you consider [and for which types of patients] in those taking phenytoin?

Answer 13

vitamin D for those immobilised for long time or with inadequate sun exposure

Question 14

what is the MHRA warning of phenytoin?

Answer 14

discontinue and report if signs of blood disorder develop

report if rash occurs

Question 15

what is the target plasma concentration range for phenytoin?

Answer 15

10-20mg/L

40-80micromol/L

Question 16

what are the toxicity signs of phenytoin? [5]

Answer 16

nystagmus
slurred speech
ataxia
confusion
HYPERglycaemia

Question 17

what are the serious interactions with phenytoin? [8]

Answer 17

• 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

Question 18

what are the side effects of PHENYTOIN?

Answer 18

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

Question 19

what are the serious side effects that can occur with topiramate?

Answer 19

cleft palate

myopia [short sightedness] with secondary angle-closure glaucoma. report any visual issues. seek specialist if you get intra-ocular pressure

Question 20

what should patients on ethosuximide report signs of/

Answer 20

bone marrow suppression

Question 21

what must a prescription for clobazam be endorsed with?

Answer 21

endorsed with SLS

Question 22

what is the MHRA warning of gabapentin?

Answer 22

risk of respiratory depression even without opioid drugs

adjust doses in pt with resp depression

Question 23

what cd schedule is gabapentin in?

Answer 23

schedule 3

Question 24

what must you observe pt taking gabapentin with and what is the advise that you must give them?

Answer 24

observe for signs of abuse/dependance

let them know that it can interact with alcohol and other drugs that cause CNS depression like opioids

Question 25

what are the Important safety warnings regaring sodium valproate?

Answer 25

- 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

Question 26

is sodium valproate an inhibitor or inducer and what does this mean?

Answer 26

inhibitor - increases conc of other drugs

Question 27

which are stronger: inducers or inhibitors?

Answer 27

inducers

Question 28

which types of patients should vitamin D supplementation be considered in and why?

Answer 28

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

Question 29

what are the side effects of sodium valproate?

Answer 29

valproate ``` valproate appetite increased [weight gain] liver failure pancreatitis and p45 inhibitor reversible hair loss oedema ataxia teratogenicity and tremor encephalopathy [brain damage] ```

Question 30

what are the important interactions with sodium valproate? [6]

Answer 30

- 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

Question 31

what is the pt and carer advice for sodium valproate?

Answer 31

- 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

Question 32

what is vigabatrin indicated for?

Answer 32

focal seizures

Question 33

what is the serious side effect of vigabatrin? what should patients report?

Answer 33

visual disturbances report any visual symptoms asap