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Flashcards in Pharmacogenomics Deck (14)
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1
Q

Guidelines for PG testing

A

Clinical Pharmacogenetics Implementation Consortium (CPIC)

2
Q

Definition of allele

A

the specific form of a gene
wild-type: usually most common type of allele
homozygous gentotype: 2 identical alleles
heterozygous genotype: 2 different alleles

3
Q

Most common cause of individual variability in response to a drug

A

sing;e nucleotide polymorphism

4
Q

Which drug requires HLA-B*5701 testing in all pts before starting?

A

abacavir (Ziagen)
can lead to fatal hypersensitivity
Do not use if + test
Other drugs that contain abacavir:
Epzicom (abacavir + lamivudine)
Triumeq (abacavir + dolutegravir + lamivudine)
Trizivir (abacavir + zidovudine + lamivudine)

5
Q

Which drug requires HLA-B*5801 testing in all pts before starting?

A

Allopurinol (Zyloprim)

Can lead to increased risk of SJS

6
Q

Which drug requires HLA-B*1502 testing in all Asian pts before starting?

A

Carbamazepine (tegretol)
incr risk of SJS and toxic epidermal necrolysis (TEN)
Do not use unless benefit clearly outweighs risk
Phenytoin (Dilantin). Fosphenytoin (Cerebyx):
Testing not required, but should be considered

7
Q

What PG testing can be used for clopidogrel?

A
CYP2C19 genotype
Clopidogrel is a prodrug that is activated by 2C19
2C19*1 = fully functioning
*2/*3 = poor metabolizes
Consider alternative treatment
8
Q

What PG testing can be used for codeine?

A

CYP2D6 genotype
Codeine is metabolized to morphine via 2D6
Ultra-rapid metabolizers are at increased risk of toxicty
Poor metabolizers have lack of efficacy

9
Q

What PG testing can be used for warfarin?

A

CYP2C9 and VKORC1
2C9 2/3 = decreased metabolism
VROKC1 G > A = decreased metabolism

start with lower dose if these are present

10
Q

What PG testing can be used for Trastuzumab (Herceptin), adotrastuzumab (Kadcyla), Pertuzumab (Perjeta)?

A

HER2 gene expression

these meds only work if HER2 is expressed 2+ or 3+

11
Q

What PG testing can be used for Cetuximab (Erbitux), panitumumab (Vectibix)?

A

KRAS mutation
for colorectal cancer
If KRAS +, DO NOT USE

12
Q

What PG testing can be used for azathioprine?

A
Thiopurine methyltransferase (TPMT)
low or absent TPMT = incr risk of myelosuppression 

statrt at very low dose or use altn treatment

13
Q

What PG testing can be used for capecitabine (Xeloda), flurouracil (Adrucil)?

A
Dihydropyrimidine dehydrohenase (DPD) deficiency
can lead to incr toxicity with these drugs
do not use
14
Q

Drugs that require or strongly recommend PG testing before using:

A
Abacavir
Azathioprine
Carbamazepine 
Cetuximab, Panitumumab
HER2 inhibitors

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