Prescription pain-relievers can be powerfully effective agents in the treatment of moderate to severe pain; however, these drugs are also strongly associated with drug abuse and addiction. In the brain, opioid analgesics bind to various receptors in the mesocorticolimbic dopaminergic pathways, which play a multifaceted interaction of role in reward. Several specific single nucleotide polymorphisms (SNPs) have been identified as potential genetic factors that increase an individual's risk for addiction; however, confounding studies and lack of large trials prohibit definitive conclusions from being drawn. As a result of genetic testing, federal and state laws have been enacted to protect individuals from discriminations. As more definitive evidence becomes apparent, a large impact on pharmacy practice is expected.