CYP2D6 ability to metabolize tamoxifen and recurrence

Received an email with links to two sites.  One is Genelex's blog site(first) It discusses a study regarding Pharmacogenomics  The second is the study.

http://genelex.com/blog/study-pharmacogenomic-knowledge-gaps-persist-among-physicians/

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4100727/

Roughly, The study identifies that only a small percentage of docs are knowledgeable about Pharmacogenomics. Earlier posts, I stated that we needed to teach our docs. The evidenced based research is there in the study.

OMD(OH MYDOG). (dislike saying OMG).

Hopeful I was thinking about PM'g you and there you are. LOL. Will PM you now.

I reread what I wrote as a synopsis. Amazed it sounds so professional. LOL

Hopeful, Bakerbaker inspired me. Couldn't do it. Today thyroid med readjustment b/c of sensitivity. Hypoing symptoms. One is thinking UGH.

Bump

Hello, Thisis an example of how a doc can use CYP genetics to direct care by using the right medications

http://genelex.com/blog/all-that-wheezes-is-not-asthma-youscript-helps-in-tough-patient-case/

Check out the genetic testing available for cancers. My own research said I should be tested for PTEN, Chek2, P53. Docs have negated it. Hmmmmmm I think I will put the links directly to the web site besides the BCO link.

https://community.breastcancer.org/forum/5/topic/829445

YOOOHOOOO Jelson & Hopeful, I'm stoked to the max. I was in Walmart ran into an old nurse friend who' s now the Oncology  nurse navigator at my old hospital. I left there in 2008. Had killer chemo in April, 2009. All Dh's Chemo's were there in 2009 and 2010. haven't had an admission there except for thyroidectomy in 2014 overnight. But no contact with the oncology unit.

With in a couple of minutes of greeting, DF says "Remember when you were doing the cytochrome thing, we do it all the time now" You were way ahead of the time". I told her I had dropped off info to Steve the lead pharmacist. That's probably what got it going. He was a proactive guy with POWER----LOL. We didn't get into details. I'm stoked. YAY, advancement.

Often through here and elsewhere. I use a phrase---"A pebble thrown into a pond creates ripples that we know not where they go"

Happy Dance

Saving this to my favs and sending this week to my doc for the script. She definitely agrees I need it. Don't care if Medicare or insurance pays or not, it's worth it....

I insisted on the test back in 2010 and was able to get it. Turned out I was an extensive metabolizer so it gave me peace of mind and decided to stay on it even after my hysterectomy since I had osteopenia. Thanks for keeping this thread going!

I still check in once in awhile to stay current on research/info. I've always found the information on here from folks like you to be the best on the internet! I often surprise my oncologist with how knowledgeable I am about "current events" in BC related news. And I feel like it helps me make an informed decision on my personal treatment choices. As most of us know, the docs are just making an educated guess a lot of the time and unfortunately sometimes an uneducated guess (in my opionion) by not keeping up on current research or by having medical biases.

Wonderful health to you in the New Year as well, sas-schatzi!

Jelson, CYP3A7 is newly found? Well good, anything that can help in treatment decisions

Shep the link to the pain management page isn't a good link. But couldn't find anything on the web site. Have you wandered genelex for similar info? The link to the Mayo site is nice, but worry that it's not complete enough. Coreg/carvedilol for example I know from my previous searching that it goes through maybe a 1/2 dozen paths., but mayo only lists one.

Since around 1998 FDA required that CYP enzyme paths be identified and included in each drug monograph. It can be located in the metabolism section of the monograph.

Glad you eventually will come here. I haven't been into keeping up with it this last while. No fun when they're isn't someone to play with

My Genelex results:

***edited to note the "aka" items in parenthesis were added by me to decipher info as I understand it - hopefully correct

CYP2D6 Normal Metabolizer *1/*1 (aka Cytochrome P450 2D6)***

CYP2C19 Ultra Rapid Metabolizer *17/*17 (aka Cytochrome P450 2C19)***

CYP2C9 Normal Metabolizer *1/*1 (aka Cytochrome P450 2C9-VKORC1)***

CYP3A4 Normal Metabolizer *1/*1

CYP3A5 Non-Expresser *3/*3

CYP2B6 Normal Metabolizer *1/*1

OPRM1 Intermediate Sensitivity c.118A>G GA

COMT Low Activity c.472G>A AA

CYP2D6 Normal Metabolizers have normal (extensive) CYP2D6 activity. Prescribe CYP2D6 metabolized drugs at standard doses. Increased caution is advised for individuals having one partially active allele, such as *9, *10, *17, or *41.

CYP2C19 Ultra Rapid Metabolizers have greatly increased CYP2C19 activity. For CYP2C19 inactivated drugs, consider prescribing increased doses or alternative treatment for optimal therapeutic response. For prodrugs that require activation by CYP2C19, consider prescribing decreased doses or alternative treatment to prevent adverse effects.

CYP2C9 Normal Metabolizers have normal (extensive) CYP2C9 activity. Prescribe CYP2C9 metabolized drugs at standard doses.

CYP3A4 Normal Metabolizers have normal (extensive) CYP3A4 activity. Prescribe CYP3A4 metabolized drugs at standard doses. Patients may still have significant variation in CYP3A4 activity due to various patient and environmental factors, despite having a CYP3A4 Normal Metabolizer phenotype.

CYP3A5 Non-Expressers (also known as Poor Metabolizers) have greatly decreased CYP3A5 activity. The majority of the population (60-90%) have this genotype, except for people of African origin. Prescribe CYP3A5 metabolized drugs at standard doses.

CYP2B6 Normal Metabolizers have normal (extensive) CYP2B6 activity. Prescribe CYP2B6 inactivated drugs at standard doses.

OPRM1 Intermediate Sensitivity patients may require normal to slightly increased opioid doses to achieve adequate pain control compared to OPRM1 High Sensitivity patients. Opioid Receptor Mu 1 (OPRM1) is one of the main receptors responsible for opioid effects. Asians with this phenotype may have increased risk of addiction to opioids compared to OPRM1 High Sensitivity patients. Naltrexone response for the treatment of alcoholism may be increased and risk of relapse decreased compared to OPRM1 High Sensitivity patients.

COMT Low Activity patients have low catechol-O-methyltransferase (COMT) activity, resulting in decreased breakdown of dopamine, epinephrine and norepinephrine. Changes in dopamine levels may have emotional and behavioral effects. Drugs directly or indirectly associated with these neurotransmitters may be impacted. This phenotype may have an increased likelihood of smoking cessation and decreased ON time with entacapone use. SSRIs, opioids and antipsychotics may also be affected, but the overall significance is unknown. Low COMT activity enhances opioid analgesia and adverse effects in some cancer pains via increasing the absolute amount of opioid receptors

Does anyone know how long it takes for tamoxifen to be metabolized by the liever, assuming a typical 20 mg dose and a "normal metabolizer" as opposed to a rapid one?