Table 2.

Genetic Variants Associated with Morphine Metabolism

Gene	SNPS	Chromosome locus	Effect of variant allele	References
UGT2B7	rs7438135	4:69095621	Drug metabolism	Höllt (2002); Duguay et al. (2004)
OPRM1	rs1799971	6:154039662	Pain and mediates analgesic effect of morphine.	Lötsch et al. (2002); Zubieta et al. (2003); Jhun et al. (2015)
ARRB2	rs1045280	17:4719343	Drug metabolism	Ross et al. (2005)
STAT6	rs167769	12:57109992	Drug metabolism	Ross et al. (2005); Jhun et al. (2015)
	rs841718	12:57099213	Drug metabolism
	rs3024971	12:57099944	Drug metabolism
COMT	rs4633	22:19962712	Drug metabolism and pain	Zubieta et al. (2003); Jhun et al. (2015)
ABCB1	rs1045642	7:87509329	Responsible for analgesia	Meineke et al. (2002); Jhun et al. (2015)