DRUGS IN EPILEPSY

Question 1

What are important safety information regarding gabapentin?

Answer 1

rare risk of severe respiratory depression
levels of propylene glycol, acesulfame K, and saccharin sodium may exceed WHO daily intake limits if high doses of gabapentin oral solution are given to adults with low body weight.

Question 2

What cautions need to be taken with gabapentin?

Answer 2

DM
Elderly
high doses in adolescents and low body weight
respiratory depression

Question 3

PHENYTOIN:
What is this licensed for?

Answer 3

tonic-clonic
focal seizures
status epilepticus

Question 4

PHENYTOIN:
What is important side effects?

Answer 4

RASH- discontinue if occurs- if mild then reintroduce
Overdose- nystagmus, diplopia, slurred speech,confusion, ataxia, hyperglycaemia
Hepatotoxicity- discontinue immediately and do not re-administer.

Question 5

PHENYTOIN:
Why is patient adherence particularly important ?

Answer 5

Narrow therapeutic index; few missed doses or over dose may lead to marked changes to plasma concentration

Question 6

PHENYTOIN:
What are contraindications?

Answer 6

Acute porphyria

Question 7

What two drugs have an increased risk of Steven Johnson syndrome if the patient has the HLAB-1502 allele?

Answer 7

Carbamazepine
Phenytoin

This is most common in patient of Chinese and Han-thai origin.

Question 8

PHENYTOIN:
What type of seizure can be exacerbated by it?

Answer 8

Myoclonic
absence

Question 9

TOPIRAMATE:
What are they used for?
What are side effects?

Answer 9

Alone or adjunct for generalised tonic-clonic seizures

acute myopia
secondary angle closure oedema-occurs one month of starting.

Question 10

Vigabatrin;

When is it used
What are important side effects?

Answer 10

focal seizures

associated with visual field defects
therefore visual field testing before treatment is needed and 6 month interval

can occur 1 month to several years

Question 11

FOSPHENYTOIN:
What is it?

Answer 11

A pro-drug of phenytoin

Question 12

FOSPHENYTOIN:
Side effects of IV infusion?

Answer 12

I.V infusion associated with cardiovascular reactions including asystole, VF, cardiac arrest, hypotension, bradycardia and heart block.

Question 13

FOSPHENYTOIN:
What are monitoring requirements during IV administration?

Answer 13

BP
Pulse
respiratory function

If hypotension occurs, reduce rate of infusion

Question 14

FOSPHENYTOIN:
When would a dose reduction be made?

Answer 14

Elderly
renal/ hepatic impairment