Are there any pharmacokinetic interactions between Lexapro and Wellbutrin?

[firedoor]

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Wellbutrin is a 2B6 substrate and 2D6 inhibitor (clinically significant only above 300 mg?).

(Es)citalopram is a 2C19, 2D6 and 3A4 substrate and weak 2D6 inhibitor.

So theoretically high dose Wellbutrin could increase Lexapro levels.

My question is whether Lexapro or Celexa in any way affect Wellbutrin levels?

More specifically, could very high dose (es)citalopram (60-100 mg) increase Wellbutrin levels?

 

[IAmAUser]

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[nitemagi]

I presume you're fishing for data to support a hypothesis based on a case you have in mind?

Overall I think it's quite a reach, BUT...

there's a couple of small papers.

There may be an alternate metabolic pathway for Bupropion of 2C19 for some of it's alternative metabolites...
http://www.ncbi.nlm.nih.gov/pubmed/20528624
One could further hypothesize for an interaction with citalopram metabolism, which may also have a 2C19 metabolic pathway (particularly for the S-enantiomer --- Escitalopram)
http://www.ncbi.nlm.nih.gov/pubmed/19773541
http://www.ncbi.nlm.nih.gov/pubmed/21192344
So theoretically there could be some protein displacement bumping active levels of WBT.

Interestingly there's some other theoretical stuff out there about 2D6 inhibition (or genetically poor metabolizers) having some indirect effect on 2C19 metabolism.
http://www.ncbi.nlm.nih.gov/pubmed/8885123
http://www.ncbi.nlm.nih.gov/pubmed/21192344 (Again)

This all goes counter to Occam's razor, of course. But as a dear colleague pointed out, there's always Crabtree's Bludgeon.

 

[firedoor]

I presume you're fishing for data to support a hypothesis based on a case you have in mind?

Yes. I have inherited one patient on Wellbutrin XL 450 mg/day and Lexapro 40 mg/day with no noted interactions clinically.

But I'm actually thinking of a case where a partial response has been achieved with Wellbutrin XL 300-450 mg/day and Lexapro 20 mg/day, but the patient may require Lexapro in the 60-100 mg/day range for severe OCD-spectrum symptoms.

Overall I think it's quite a reach, BUT...

there's a couple of small papers.

There may be an alternate metabolic pathway for Bupropion of 2C19 for some of it's alternative metabolites...
http://www.ncbi.nlm.nih.gov/pubmed/20528624
One could further hypothesize for an interaction with citalopram metabolism, which may also have a 2C19 metabolic pathway (particularly for the S-enantiomer --- Escitalopram)
http://www.ncbi.nlm.nih.gov/pubmed/19773541
http://www.ncbi.nlm.nih.gov/pubmed/21192344
So theoretically there could be some protein displacement bumping active levels of WBT.

Interestingly there's some other theoretical stuff out there about 2D6 inhibition (or genetically poor metabolizers) having some indirect effect on 2C19 metabolism.
http://www.ncbi.nlm.nih.gov/pubmed/8885123
http://www.ncbi.nlm.nih.gov/pubmed/21192344 (Again)

This all goes counter to Occam's razor, of course. But as a dear colleague pointed out, there's always Crabtree's Bludgeon.

Very interesting and helpful information...thanks! My primary concern is whether very high dose Lexapro might effect Wellbutrin levels such that there is a clinically significant increased risk of seizures. Any further thoughts or suggestions would be greatly appreciated.