Pharmacogenomics 2 Flashcards
What are the pharmacogenetic phenotypes that affect the pharmacokinetics?
Polymorphisms in enzymes or drug transporters
What are the pharmacogenetic phenotypes that affect the pharmacodynamics?
Polymorphisms that affect receptors or enzymes..
Alters drug response.
What are the major gene polymorphisms that affect pharmacokinetics?
CYPs
Drug transporters
CYP2D6 affect which three major drugs?
Tamoxifen
Codeine
Paroxetine
How many different polymorphisms occur in CYP2D6? What do these cause?
12–non-functional alleles
What is the genetic makeup of ultra metabolizers with CYP2D6?
Three copies of the CYP gene
What is the genetic makeup of poor metabolizers with CYP2D6?
Two non-functioning copies of the CYP genes
What is the genetic makeup of intermediate metabolizers?
Single active gene. Other is inactive.
What is the genetic makeup of Enhanced metabolizers?
Two copies of the CYP gene
What enzyme metabolizes tamoxifen?
CYP2D6
What are the active metabolites of tamoxifen?
4OH Tamoxifen
Endoxifen
What is the effect of poor metabolizers of CYP2D6 with tamoxifen?
Cannot convert tamoxifen into active forms well.
What is the MOA of tamoxifen?
Binds to ER for breast CA
What is the clinical significance of poor CYP2D6 metabolizers on Tamoxifen?
if poor, then consider different drug
What is the relationship between CYP2D6 and codeine?
Codeine is a prodrug that needs to be activated by codeine.
What are the three possible metabolites of codeine? Which are active/inactive?
Norcodeine or codeine-6-glucuronide
Morphine
What is the clinical significance of CYP2D6 and codeine?
Poor metabolizers will not get effect/inadequate analgesia
What is the relationship of Paroxetine and CYP2D6?
Poor metabolizers will have increased plasma levels, and more side effects.
Ultra Metabolizers will have no effect
What are the two drugs that are metabolized by CYP2C19?
Clopidogrel
Omeprazole/Lansoprazole
What is the MOA of clopidogrel?
Inhibits ADP on platelets
What is the relationship between clopidogrel and CYP2C19?
poor metabolizers will need higher dose d/t lower generation of active metabolites
What is the enzyme that metabolizes Clopidogrel?
CYP2C19
What is the enzyme that metabolizes Omeprazole?
CYP2C19
What is the enzyme that metabolizes Lansoprazole?
CYP2C19
What is the enzyme that metabolizes Codeine?
CYP2D6
What is the relationship between CYP2C19 and omeprazole/lansoprazole?
Poor metabolizers have higher cure rates–do not clear drugs as fast
What is the drug that CYP2C9 metabolizes?
Warfarin
What enzyme clears warfarin? What does it turn it into?
CYP2C9
Hydroxywarfarin
What is the MOA of warfarin?
inhibits Vitamin K epoxidase (VKORC1)
What is the relationship between CYP2C9 and warfarin?
Slow metabolizers need a lower dose, o/w risk of bleeding
What are the two enzymes that can change the efficacy of warfarin? How does each do this?
CYP2C9 = pharmacokinetics
VKORC1 = pharmacodynamics
What is the least active polymorphisms of VKORC1?
VKOR1AA has the lowest activity
What is the use of dasatinib? Target?
CML– phili chromosome
What is the use or imatinib? Target?
CML – phili chromosome
What is the use of erlotinib? Target?
Metastatic non-small cell lung CA– EGFR
What is the use of Trastuzumab? Target?
HER2
Breast Ca
What is the use of cetuxiamb? Target?
EGFR
Metastatic colorectal CA
What are the enzymes that metabolize 5FU?
DPD (dihydropyrimidine dehydrogenase)
TYMS (thymidylate synthetase)
What is the enzyme that metabolizes 6MP?
TPMT (thiopurine methyltransferase)
What is the adverse effect of not screening for DPD or TYMS prior to giving 5FU? MOA?
Severe myelosuppression
Causes DNA damage by decreasing dTTP levels
What is the use of 5FU?
Breast CA, neck CA
What is capecitabine?
Prodrug of 5FU
What is the function of DPD in 5-FU metabolism? How can polymorphisms affect this?
Inactivates it
Changes pharmacokinetics
What is the relationship between 5-FU and TYMS? How can polymorphisms affect this?
TYMS is what 5FU inhibits
Changes pharmacodynamics of 5FU
What is the relationship between 6-MP and TPMT? Changes in TMPT cause what?
TMPT inactivates 6-MP
Pharmacokinetics change
What is 6MT used to treat?
Lymphoblastic leukemia
What is the adverse effect of not screening TPMT with 6-MP use?
Severe myelosuppression and secondary CA
What is the transporter of simvastatin? What is the effect of polymorphisms in this?
Solute carrier organic anion transporter 1B1 (SLCO1B1)
Changes pharmacokinetics
What are the three different genotypes of SLCO1B1?
T/T = normal T/C = Decreased transport C/C = low transport
Polymorphisms in what part of the estrogen receptor leads to varying effects? What effects are seen?
Between the 1st and 2nd exons of the ER-alpha gene
This causes a greater increase in HDL level following HRT
What is the gene that changes albuterol use? What does this change?
ADRB2
Will decrease response to albuterol due to changes in responsiveness of B2 receptor
Passive smoking has what effect on ADRB2?
Appears to augment the down regulate the effect of metabolism in the weak metabolizers
What are the two common genetic changes in the coagulation cascade that can increase thromboembolisms?
Factor V and prothrombin
What allele causes a hypersensitivity reaction against abacavir? Does this affect the pharmacokinetics/dynamics?
HLA-B 57:01
No effect
Pts with the HLA-B 57:01 polymorphism should not receive what drug? Why?
Abacavir
Hypersensitivity–steven johnson syndrome
Absence of certain alleles in what gene correlate with better therapeutic success for alzheimer’s disease with tacrine?
APOE
Absence of certain APOE alleles improves what part of Alzheimers treatment?
Better success with Tacrine
What is the common treatment for HBC and HBV? What is the genome that has a highly predictive response to treatment?
IFN-alpha
IL-28
What are the two genotypes of Il-28 that affect the response of IFN-alpha treatment?
CC = favorable
CT or TT = unfavorable