Page 1 of 1: q 83 phentoin ADR case [Ongoing d/w Dr Himanshu Tyagi]

doctorgirl78 · Credits: 5486 My Scrapbook

Q 83. pt w’ GTC develops drug rxn to phenytoin……..most appropriate course of action………

A,shift to clonazepam
B.restart phenytoin after 2 wks
c.shift to valproate
d.shift to ethosux

Now I hope I am not wrong here………but whoever has answered this question in the book has based all reasoning on a presumption that pt. got phenytoin toxicity so he should be treated for it……

But there are two things I differ about--his traeting the caseas of toxicity and two its Rx with clonaepam
heres what i think

One –patient had ADR..stop the drug
Two—patient needs AED .for GTC valproate is the DOC (it’s a wonder why anybody gave him pheny in th first instance!!!)

If I remember AED well,clonaepam and etho have NO ROLE in partial or generalized seizures……..

What say you?

I’ll go for c as the answer

ruchi · Credits: 2748 My Scrapbook

ditto!!!
i'll go for the same i.e. valproate.

drhimanshutyagi · Credits: 251 My Scrapbook

Page 90, Question 83, RxPG AIIMS May 2003 Book

Thanks for this constructive bit of discussion. This topic has also been discussed at:

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Option 1. I agree with Pilgrim, Ruchi and Doctorgirl regarding clonazepam having no role in GTCS when Valproate is an option. But clonazepam can be used as an emergency stop gap arrangement in all cases of epilepsy.

Option 2. Regarding restarting phenytoin sodium after two weeks, this can be considered if the hypersensitivity is mild, but i will go against this option as:
1. There is no mention of the degree of severity of hypersensitivity in the question
2. On restarting phenytoin, if there is even slighest of hint of a rash, then it has to be stopped immediately and for ever.

Option 3. Shift to sodium valproate is the option being discussed as an answer by the students in this forum thread. I do agree with them partially but they overlooked a crucial aspect of the question. It has been mentioned in question that the GTCS is of recent origin. I agree that valproate is the drug of choice, but why then she is on it. Had it been a case of long standing epilepsy, we can deduce that the patient has been shifted from valproate to phenytoin due to non response. But Phenytoin to be there indicates a hypersensitivity/contraindication problem with Valproate in the first place. Although this can be only a presumption, but it appears to be to strong. I invite the opinion of the users regarding this. Patients who have experienced hypersensitivity with phenytoin should avoid arene oxide anticonvulsants (carbamazepine, phenytoin and phenobarbitone) in the future.

Option 4. Ethosuximide is not an option to be considered as an answer here. It is DOC in Absence seizures. Although it can be used in GTCS theoritically, it is rarely used for this purpose.

So the question is still wide open. I ll be looking for more discussions and references before releasing an official errata about it. Meanwhile can somebody write to the AIIMS exam body or contact the medicine faculty there highlighting the insufficiency of the question itself. I know of cases when AIIMS has resolved such queries. And if you do get an answer, dont forget to share it here.

You have to decide between clonazepam and valproate as an answer.

Thanks

Dr Himanshu Tyagi

doctorgirl78 · Credits: 5486 My Scrapbook

I have been given this book by a DM Neurology yrs into practice to solve this question:
Handbook of epilepsy by Browne & Holmes
Publishers
Lipincott-raven
Page 164
Updated every year for latest FDA guidelines............
Regarding choosing a drug for primary generalized seizures, it recommends both phenytoin and valproic acid as first line drugs
And carbamazepine as the second line drug

Valproic acid is to be preferred if a component of absence seizures or myoclonic seizure is suspected in pt with primary generalized seizure.(which is a well known combination of seizure types)
In a patient with isolated primary GTC, either may be used.

So this justifies why our neurologist chose phenytoin for this patient. It’s a recent onset seizure, he tried phenytoin, pt had a rxn now he’ll try valproic.seems jusfiable now?

Ethosuximide & clonazepam have been ruled out as useful in GTC.
Restarting phenytoin is out of question……..this is what the Doc had to say for choice:2
Try suggesting the patient (who knows his AED will continue for yrs and is already embarrassed at the diagnosis in the first place) that the drug that gave him a rash will be started after 2 weeks, you’ll never see him again in your OPD.

So I gathered what I could………the ball’s in your court now.

syndrome_xy · Credits: 10947 My Scrapbook

the answer is valproate obviously...

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