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. 2020 Jan 28;26(1):129–133. doi: 10.4103/IJPC.IJPC_155_19

Table 1.

SNPs associated with nonopioids and opioids and its clinical consequences in pain management

Drug Genotype/SNP Clinical consequences Reference

Metabolizing enzyme: CYP2D6
Codeine Poor metabolizer Lack of efficacy [9,10]
CYP2D6*3, CYP2D6*4, CYP2D6*5,
CYP2D6*6, CYP2D6*7, CYP2D6*8,
CYP2D6*11
Ultrarapid metabolizer Increased toxicity
CYP2D6*1xn
CYP2D6*2xn
Tramadol Poor metabolizer Reduced analgesia and increased risk of side effects [11]
CYP2D6*3, CYP2D6*4, CYP2D6*5,
CYP2D6*6
Ultrarapid metabolizer Increased toxicity
CYP2D6*1xn
CYP2D6*2xn
Oxycodone Poor metabolizer Decreased response and lack of efficacy [12]
CYP2D6*3, CYP2D6*4, CYP2D6*5,
CYP2D6*6
Ultrarapid metabolizer CYP2D6*1xn Increased metabolism and high risk of toxicity/side effects
CYP2D6*2xn
Methadone CYP2D6*10, CYP2D6*87, CYP2D6*89, Decreased analgesia and/or increased toxicity [13]
CYP2D6*90, CYP2D6*93, CYP2D6*95,
CYP2D6*97, CYP2D6*98

Metabolizing Enzyme: CYP2C9

NSAIDs, celecoxib, diclofenac CYP2C9*2 Increased risk of GI bleeding [14]
CYP2C9*3

Cyclooxygenases 1: PTGS1

NSAIDs PTGS1 (4331 A>T) PTGS1 4331T variant allele Increased risk of acute coronary syndrome [15]

Cyclooxygenases 2: PTGS2

Rofecoxib PGTS2 (−765G>C) PGTS2-765C variant allele Poorer pain relief [16]

Opioid receptor µ: OPRM1

Morphine OPRM1 118A>G Needs larger doses of morphine for pain control [17]
Mutant 118G allele

Opioid receptor kappa: OPRK1

Morphine OPRK1 (36 G>T) Increased dose escalation of morphine is required in cancer related pain [18]

Opioid receptor delta: OPRD1

Opioids OPRD1 921T>C Increased risk of opioid dependence in variant allele of OPRD1 [19,20]

Others: Phospholipase C gamma 1 (plus strand)

Acetaminophen and diclofenac, aspirin, propionic acid derivatives or pyrazolones PLCG1 Ser 279 Gly Increased risk of angioedema [21]

HLA-DQB1

Acetaminophen HLA-DQB1*02:02 Increased risk of cutaneous adverse reactions [22]

SNP: Single-nucleotide polymorphism, CYP2D6: Cytochrome P450 2D6, CYP2C9: Cytochrome P450 2C9, NSAIDs: Nonsteroidal anti-inflammatory drugs, PTGS: Prostaglandin-endoperoxide synthase, HLA-DQB1: Major histocompatibility complex, class II, DQ beta 1, GI: Gastrointestinal