# Drug interactions question, calling all pharmacists!! **URL:** \ **Category:** Factual Questions\ **Created:** [January 20, 2009, 7:34pm UTC](https://boards.straightdope.com/t/drug-interactions-question-calling-all-pharmacists/482188 "2009-01-20T19:34:53Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![Anise](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/anise/32/21721_2.png) [@Anise](https://boards.straightdope.com/u/Anise)\ **Post date:** [January 20, 2009, 7:34pm UTC](https://boards.straightdope.com/t/drug-interactions-question-calling-all-pharmacists/482188/1 "2009-01-20T19:34:53Z")
And doctors… and science-y types… but pharmacists are the ones who actually tend to know the most about the interactions in my experiences, to be perfectly honest… Okay, I can’t find this info anywhere. A lot of drugs are metabolized through the P450 enzyme pathway, which means that they are interfered with by a.) each other and b.) grapefruit juice, pomegranate juice, and starfruit, although people who are REALLY sensitive to the effects may also notice them with wine grapes and a few other things. So you have drugs that are substrates (like Seroquel and Tegretol) drugs that are inhibitors, which means they increase the amount of the substrate drugs (like a lot of antibiotics, grapefruit juice and so forth also do this) and then drugs that are inducers; these decrease the amount of the substrate drugs (Topamax does this.) Here’s a nice table: [http://www.medicine.iupui.edu/Flockhart/table.htm](http://www.medicine.iupui.edu/Flockhart/table.htm) So here I am, taking Seroquel. When I unknowingly ate a pomegranate a day for a month, I basically did the same thing as taking 70% more Seroquel, which was NOT a good thing at all. I started on Topamax a month and a half ago. If I were taking a lot more of it than I am, it would _decrease_ the concentration of Seroquel in my system, making it the same as if I were taking _less_ Seroquel. Seroquel is in the middle; pomegranate and grapefruit and all the other inhibitors are on the other side, Topamax and all the other inducers are on the other side. (specifically, all CyP3A4 inducers or inhibitors, actually, but it’s not necessary to know that for the purposes of this.) When on vacation in Denver, I got VERY sick and took antibiotics that were also P450 inhibitors. So here’s my question: I know what effect they had on Seroquel; they inhibited the enzyme and effectively increased the dose. But what was the effect on Topamax? In other words, what effect does a P450 _inhibitor_ have on an _inducer_? Does anyone have any idea??? ---
**Author:** ![Joey\_P](https://avatars.discourse-cdn.com/v4/letter/j/919ad9/32.png) [@Joey\_P](https://boards.straightdope.com/u/Joey_P)\ **Post date:** [January 20, 2009, 7:42pm UTC](https://boards.straightdope.com/t/drug-interactions-question-calling-all-pharmacists/482188/2 "2009-01-20T19:42:38Z")
Didn’t we already do this? ETA Yup > **[Mid-South Dopers: when did pomegranates appear in large quantities this year??](https://boards.straightdope.com/sdmb/showthread.php?t=494413)** > > Hi… (waves) Pomegranate season started fairly recently around here (Nashville), and I love pomegranates. I was eating at least one or two a day, and they were the really large ones. I was plunged into the most horrible black depression imaginable. I... ETAETA Nevermind, I didn’t see the Topamax part at the bottom. ---
**Author:** ![Anise](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/anise/32/21721_2.png) [@Anise](https://boards.straightdope.com/u/Anise)\ **Post date:** [January 20, 2009, 8:18pm UTC](https://boards.straightdope.com/t/drug-interactions-question-calling-all-pharmacists/482188/3 "2009-01-20T20:18:34Z")
Same person, same enzymes, different question. 🙂