27 Apr 2018

Cytochrome P450, Drug Interactions, & Secondary Porphyria


I’ve read a good deal of discussion about these issues since starting on CAP. Perhaps I’ve overlooked something in the archives, but I’ve read some recent sources that have given me new information about this complex topic.   Cytochrome P450 (CYP) is an isoenzyme, so called because it is closely related to other variants by homologous genes. They are named by a root (CYP), family (a number), a subfamily (a letter), and then the gene (another number). So, for example, one isoenzyme goes by the name of CYP2D6. CYP isoenzymes in the same family and subfamilies share structural similarities.



 thanks cchase. This information has really helped me, I am not on CAP but I suffered major porhyriac symptoms while on a month long course of antibiotics and have a lot of continuing symptoms still 5 months after the treatment. I have a CPN IgG titre of 1:256 and I suspect that this is what is causing my poor health but I haven't been tested at the right time to show elevated porphyrins.I read that it is possible to be tested for the CYP 450 enzymes but I don't know what this involves or where it is possible to be tested - does anyone out there know whether this is available? or what is involved?

Thanks CChase and Daisy for these posts.  I want to keep touch with this discussion.

Louise USA.CFS.CPn Positive.BbPositive.WheldonCAP6/24/07.NAC,Doxy,Roxi, Tinidazole Pulses. VitD-3,4000IU. Intermittent Cholestyramine 1-2 packets atbedtimewithpulses&asneeded forporphoria&endotoxins. 

  • CAP(TiniOnly): 06/07-02/09 for CFS
  • MethylationProtocolSupplements: Started08/08
  • Intermtnt CAP: 02/09-02/10
  • Full MethylProtocol & LDN 02/09
  • Off CAP: 02/10, cont LDN & MethlyProtocol support


Found this post very helpful !  Thanks!

In my ever increasing quest to understand the fine differences in drugs and the induction of porphyria I will add THIS article on

Cytochrome P450: New Nomenclature and Clinical Implications

from American Family Physicians.    Think the PharmD's who wrote this did a superb job of explaining the issues and pathways complete with drug examples per pathway. 

The more I know the less I know.

Daisy - Husband on CAP 5/07.   Roxithromycin, Minocycline, Rifampin, Bactrim DS, Mepron, Prednisone, Novantrone, Doxy, Azithromycin, Flagyl, Diflucan

Daisy - Husband on CAP 5/07.  Husband died from Acute Myelogenous Leukemia Secondary to the Infusion of Novantrone.  Ie - the treatment with the conventional MS drugs killed him. Daisy on her own CAP 11/2012. 

 I too did this research back a few years ago when my porpheria test was elevated. It is very helpful to know this info, it can make a huge difference in choices of meds

CPN pcr and antibody positive , treating MS, CFS, TMJ, trigeminal neuralgia, IBS neutropenia, pus found in facial bone, Doxy 100x2, zithro 250x1 alternate days. Metro pulses each month.


 cchase- ditto. You've done a magnificent job of rendering some very complex material within my grasp! I really appreciate it. It's a really useful piece of information that may help people sort out why some agents in combination are increasing their porphyria.

I'm going to attach this to the Handbook appendices so it's easy for folks to locate it and it doesn't get buried in the vast vaults of the forum. I have this image of all the treasures in posts on the forum being like those crates in the Indianna Jones movie, gathering dust in that goverment secret warehouse!

CAP for Cpn 11/04. Dx: 25yrs CFS & FMS. Currently: 300mg BID Roxithromycin, Bactrim DS 2x/day, Tini 1000mg/day pulses; Vit D2000 units, T4 & T3

cchase,  Thank you for the time and care you have taken to present this important information.  It's much better to know, isn't it?

Joyce~caregiver-advocate in Dallas for Steve J (SPMS).  CAP since August 06, Cpn, Mpn, B. burgdorferi, systemic candidiasis, EBV, CMV & other herpes family viral infections, elevated heavy metals, gluten+casein sensitivity. 

Joyce~caregiver-advocate in Dallas for Steve J (SPMS).  CAP since August 06, Cpn, Mpn, B. burgdorferi, systemic candidiasis, EBV, CMV & other herpes family viral infections, elevated heavy metals, gluten+casein sensitivity.