T. Onojighofia,1 D. Holman,2 B. Akindele,1 B. Meshkin,2 R. Alexander,2 D. Schwarz,1 J. Hubbard2; 1Proove Biosciences, Columbia, MD, 2Proove Biosciences, Irvine, CA
BACKGROUND: Morphine is an opioid analgesic drug and regarded as the gold standard, or benchmark, of analgesics used to relieve intense pain and suffering. However, the role of genetics in individual variations in response to morphine use clinically is not clearly understood. The objective of this study was to determine the role of genetics in individual variations in response to prescription morphine use.
METHODS: The study included 80 chronic pain subjects taking only morphine from five research sites in the US. Subjects taking other prescription opioids were excluded from the study. Subjects were divided into two groups based on their MED Scale response (a scale of 0-5 of medication efficacy): poor responders had a score of 0 to 3 while good responders had scores 4 or 5. Subjects were genotyped with the proprietary Proove Narcotic Risk Genetics Profile using TaqMan SNP genotyping assays (Life Technologies, Carlsbad, CA). It consists of a panel of 12 SNPs (DRD1 -48A>G, DRD2 A1 allele, DRD4 -521C/T, DAT1, COMT Vall58Met, OPRK1 36G >T, OPRM1 A118G, DBH -1021 C/T, 5-HT2A -1438G/A, 5-HTTLPR, Gamma-Aminobutyric Acid (GABRA 6) (1519T>C GABA(A) alpha 6 gene), and MTHFR C677T).
RESULTS: OPRK was found from a cross tab analysis using IBM SPSS to be have an association with response to prescription morphine use (P=0.035, likelihood ratio 0.032 and Fishers Exact 0.046). Age was positively correlated with morphine therapeutic response P= 0.035. An independent sample T Test Showed a statistically significant difference between age and morphine response. P=0.029.
CONCLUSION: This study showed that OPRK may play a role in the individual variations in response to prescription morphine. In addition, the study suggests that older people are likely to respond better to morphine therapy than younger people.