Ate a large acmount of citrus while on Phenytoin

[no.guru]

Forgot about the warnings against eating citrus while on Phenytoin, and I ate about a dozen Clementines yesterday. I've eaten them before on this drug, but usually only 3 or 4. Never anywhere close to this many.

What can I say - they were on sale.

Of course, in the future I won't eat them at all.

Beginning last night I had a rash on my upper legs and arms. This morning the rash had disappeared but has come back on my arms and lower legs. Itches slightly but not much.

I know the warnings about rashes and Phenytoin/Dilantin, but I resumed this drug late last year after being on it for years prior to that. I'm skeptical this is a reaction to the drug but of course I know that's possible. I'm almost certain it's a reaction to the citrus. I've never had a rash before, but I've also never eaten nearly as much as I ate yesterday.

Also last night I had slight dizziness like I've had before when my Phenytoin blood level isn't right. I feel fine today.

Has anyone else heard of this reaction to citrus while on Phenytoin/Dilantin?

 

[Nakamova]

I've never seen any warnings about interactions between citrus and Phenytoin/Dilantin (I was on Dilantin for a few years). There is a warning about grapefruit and certain AEDs, but that's specific to grapefruit only.

Maybe you just have a citric acid intolerance? Phenytoin sometimes contain citric acid as a binder/filler, so perhaps the combination with the Clementines was enough to push you over the edge. Clementines have a lot of sugar, so might be part of the problem too, depending on what else you ate yesterday.

 

[no.guru]

Thanks for your response.

There's a page at livestrong about Dilantin that mentions citrus fruits in general, but you could say the references are rather non-specific.

Citric acid intolerance and/or too much fructose. I'm going with that assumption for now. Thankfully, the rash seems to be subsiding somewhat, too.

 

[Nakamova]

Okay, I checked the Livestrong reference -- it seems it's the folate in certain fruits and vegetables that might affect Dilantin absorption. It would be unusual to consume enough folate in your normal diet to do that, but 12 clementines would give you about half of your RDA of folate in one go. If you also consumed other folate-rich foods yesterday, or were taking a B Complex supplement, it's possible that you might have ingested enough to nudge your Dilantin levels slightly out of whack. It's not a straightforward process though: High levels of folate can lower blood levels of phenytoin, but at the same time, high levels of phenytoin can lower blood levels of folate! I was actually prescribed a folate supplement while on Dilantin.

Anyway, I'm glad you're feeling better!

 

[no.guru]

Seems I spoke too soon. The rash varies with time, and came back this afternoon. Tonight it's over my lower legs and still somewhat on my inner forearms.

With my blood level feeling different last night, though, I don't think it's likely it's unrelated to e. Will keep the thread updated, though.

Still unsure if it's related to sugar intake, but today I had one apple and a couple of cups of cranberry juice. No other sugar or dairy.

Edit: This is strange. Tonight the rash has moved to my extremities, mostly. Hands, where it's very itchy, and lower legs and feet. Symmetrical. Going back to WebMD's symptom checker.

 

[no.guru]

Just to update and close out the thread, the rash seems to be almost done with me.

It looks like the cause was citrus acidity, but that's my opinion.

Moral of the story is if you're on Dilantin/phenytoin then it's advisable to severely limit or eliminate citrus, not just grapefruit.