Epilepsy 4: Antiepileptic drugs BNF overview

Question 1

Carbamazepine is the first line drug for which type of seizure?

Answer 1

first-line options for treating newly diagnosed focal seizures

Question 2

why is it essential to initiate carbamazepine therapy at a low dose and to titrate slowly?

Answer 2

1) may exacerbate tonic, atonic, myoclonic and absence seizures
2) therefore not recommended if these seizures are present.

Question 3

Oxcarbazepine is licensed as monotherapy or adjunctive therapy for the treatment of what type of seizure?

Answer 3

Focal seizures with or without secondary generalised tonic-clonic seizures (Carbamazepine and lamotrigine are first-line options)

Question 4

Ethosuximide is a first-line treatment option for what type of seizure?

Answer 4

absence seizures

Question 5

Gabapentin and pregabalin are used for the treatment what type of seizures? (Sch 3 (CD No Register Exempt Safe Custody)

Answer 5

Focal seizures with or without secondary generalisation. not first line options

Question 6

1) Lamotrigine is first line treatment for what types of seizures?
2) What type of seizures may be exacerbated by lamotrigine?

Answer 6

1) Focal seizures and primary and secondary GTC seizures

2) Myoclonic seizures

Question 7

what side effect can lamotrigine cause, especially in children?

Answer 7

Serious skin rashes

Question 8

how do the following affect the plasma-lamotrigine concentration:

1) Valproate
2) Enzyme-inducing antiepileptics

Answer 8

1) Valproate: increases plasma-lamotrigine concentration

2) Enzyme-inducing antiepileptics reduce plasma-lamotrigine concentration

Question 9

1) Phenobarbital is effective for tonic-clonic and focal seizures, what side effect can it cause?
2) what might occur when this drug is being withdrawn?

Answer 9

1) May be sedative in adults

2) Rebound seizures may be a problem on withdrawal

Question 10

Phenytoin is licensed for tonic-clonic and focal seizures. what type of seizures should it be avoided in?

Answer 10

Absence or myoclonic seizures

Question 11

Monitoring of plasma-drug concentration is important when adjusting doses of phenytoin. Explain why

Answer 11

1) Narrow therapeutic index and the relationship between dose and plasma-drug concentration is non-linear
2) small dosage increases may produce large increases in plasma concentration with acute toxic side-effects.

Question 12

Fosphenytoin, is a pro-drug of phenytoin, why might it be more convenient to give in certain circumstances?

Answer 12

Unlike phenytoin (should only be given IV), fosphenytoin may also be given by IM injection

Question 13

what information should female patients be informed about with regards to using topiramate?

Answer 13

Female patients should be fully informed of the risks related to the use of topiramate during pregnancy and the need to use effective contraception

Question 14

sodium valporate is first line treatment for which type of seizures?

Answer 14

1) Primary generalised tonic-clonic seizures (effective)
2) Absence seizures
3) Myoclonic seizures
4) Atonic and tonic seizures

Question 15

Sodium valproate has widespread metabolic effects, as a result what should be monitored?

Answer 15

liver function tests and full blood count

Question 16

what type of seizures can Zonisamide be used for?

Answer 16

Focal seizures with or without secondary generalisation in adults with newly diagnosed epilepsy

Question 17

Fosphenytoin has been associated with severe cardiovascular reactions including asystole, ventricular fibrillation, and cardiac arrest. What monitoring is recommended to manage this? (4)

Answer 17

1) monitor heart rate, blood pressure, and
respiratory function for duration of infusion
2) observe patient for at least 30 minutes after
infusion
3) if hypotension occurs, reduce infusion rate or
discontinue
4) reduce dose or infusion rate in elderly, and in
renal or hepatic impairment

Question 18

What side effects can occur in those prescribed Vigabatrin and how should this be managed?

Answer 18

1) Associated with visual field defects- onsets varies from 1 month to several years after starting. defects may persist despite discontinuation.
2) visual field testing before treatment and at 6-month intervals. Patients warned to report any new visual symptoms - urgent ophthalmological referral

Question 19

Encephalopathic symptoms can occur with the use of Vigabatrin. List some the features that might occur and state how this side effect should be managed.

Answer 19

1) marked sedation, stupor, and confusion with non-specific slow wave EEG can occur rarely
2) reduce dose or withdraw.