Pharmacogenomics

Question 1

HLA-B *5701 allele genomic testing for what drug

Answer 1

abacavir (Ziagen), and combination product (Triumeq, Epzicom)

*if positive avoid use - hypersensitivity, fatal

Question 2

HLA-B*1502 genomic testing for what drug

Answer 2

carbamazepine (Tegretol) oxcarbamezepine (Trileptal)
phenytoin (Dilantin)
fosphenytoin (Cerebyx)

*if positive avoid use

Question 3

TPMT deficiency

Answer 3

azathioprine (Imuran)

*increase risk of myelosuppression

Question 4

-KRAS mutation

Answer 4

cetuximab (Erbitux) and panitumumab (Vectibix) - used in colon cancer

*if negative can receive drug

Question 5

+HER2 overexpression

Answer 5

trastuzumab (Herceptin), ado-trastuzumab emtansine (Kadcyla), lapatinib (Tykerb), and pertuzumab (Perjeta)

*use drugs if positive

Question 6

CYP2C19

Answer 6

clopidogrel (Plavix) - prodrug

*if poor metabolize, will not convert to active form

Question 7

CYP2D6

Answer 7

Codeine

*ultra-rapid metabolizers - converts codeine to morphine; avoid in children

Question 8

Pharmacogenomic test for allopurinol

Answer 8

HLA-B*5801

*if positive- at risk of severe skin rxn

Question 9

Warfarin does not require pharmacogenomic testing but I can be used to identify at-risk patients if:

Answer 9

1. If pt has diminished expression of CYP2C9 enzyme will be at higher risk for bleeding since less of the warfarin will be metabolized to an inactive metabolite.
2. If pt produces less VKORC1 they require a lower dose of warfarin and reduce ability to metabolize drug.

Question 10

DPD deficiency

Answer 10

capecitabine (Xeloda)
fluorouracil

*if deficient, do not use - neutropenia, diarrhea, neurotoxicity