Phenytoin

Now, sulfa drugs are a classic historical trigger, but what else causes this?

It is worth noting that modern data frequently implicates medications like Bactrim, allopurinol, and anticonvulsants like Dilantin.

And the severity of this desquamation dictates the diagnosis, right? It is all based on the percentage of total body surface area involved.

Correct.

One other part about her is that she had epilepsy.

And Patricia took a couple different medicines, Dilantin and phenobarbital, to control her seizures.

And shortly before she disappeared, she had begun having seizures again.

And because of that, her driver's license had been suspended.

So we was being treated with those.

That meant we had to, since we were reducing the abnormal SCN2A, we had to reduce then the doses of his small molecule like Dilantin.

And one of the great things is we were able to get him entirely off of these other sodium channel blockers, which have a lot of side effects.

And so he's had tremendous improvement.

In medically complex patients it's worth knowing that the proton pump inhibitor omeprazole is a 2C19 inhibitor.

For CYP2C9, the main drug to remember is phenytoin.

Phenytoin is a substrate, so 2C9 metabolizes it, and phenytoin is a 2C9 inducer, so it acts on the liver to increase 2C9 enzyme activity.

These are two separate properties.

2C9 acts on phenytoin, while phenytoin increases 2C9 activity.

The result is autoinduction.

Phenytoin accelerates its own metabolism over time, so its clearance rises and serum levels fall during the first weeks of therapy, unless the dose is adjusted.

Valproate is also partially metabolized by 2C9, but this is only a minor pathway for valproate since most of it is metabolized through phase 2.

Yeah, yeah, yeah.

During moments like those, Nixon would medicate with alcohol, along with sleeping pills and an anti-seizure drug called Dilantin that Nixon used for depression, even though that isn't actually what that drug was for.

Yeah.

And Dilantin had serious side effects, transient nervousness, mental confusion.

Yeah.

And this combination of sleeping pills and Dilantin and alcohol could be a potent and toxic stew.

And as we were saying, even with alcohol alone, apparently three drinks, three drinks would turn Nixon into like crazy drunk Nixon.

Really? Yeah.