Tamoxifen and Trancor

Warrior517

Hi....I know there has been so much info on anti-depressants and Tamoxifen lately.  I discontinued Wellbutrin after a year. My doctor, who is a big believer in supplements, put me on Trancor...GABA and Glutamate Balance Formula by Metagenics.(For anxiety..more or less)  Now, I wonder if this product could be interacting w/Tamoxifen, too.

Does anyone know any info on this?? Thanks so much!!

orange1

Never heard of trancor, but I'd be careful of taking supplements with tamoxifen, especially because you are Her2+. 

Tamoxifen is a prodrug - meaning it has to be metabolized by the body into its active form called endoxifen.  This is done by an enzyme system called CYP2D6.  This enzyme system is easily disrupted by many many drugs.  There is no reason to think it is any more stable with supplements than with drugs.  For Her 2- women, if you mix tamoxifen with something that disturbs the CYP2D6 enzyme - you end up with a greater chance of recurrence.  For Her2+ women, because of "crosstalk" between the Her2 receptor and the ER receptor (which is stimulated by the unmetabolized tamoxifen) you get a much, much, much greater chance of recurrence.   

Since you are Her2+ it is very important that you metabolize tamoxifen correctly.  Another way that tamoxifen metabolism can be off is genetics.  Approximately 60 -70% of caucasians and african americans metabolize it normormally.  About 7% metabolize it very poorly (called poor metabolizers) and most of the rest are intermediate metabolizers.  Probably, and I am definitely speculating here, Her 2- are fine even if intermediate metabolizers.  But Her2+ , who are super sensitive to unmetabolized tamoxifen should almost certainly be on an AI instead.  I recommend that you get tested to see if you are an extensive metabolizer (tamox if fine for you) or IM or PM (as Her 2+, stay away from tamoxifen).