Genetics May Explain Why Some Need High Opioid Doses for Pain Control
|The following article features coverage from PAINWeek 2017 in Las Vegas, Nevada. Click here to read more of MPR's conference coverage.|
According to results of a study presented at PAINWeek 2017, a high percentage of severe chronic pain patients had genetic variations in dopamine receptors and a low variation in opioid receptors, possibly explaining why some patients may require increased doses of opioids for pain control.
The study performed genetic testing on 70 patients with severe chronic pain that were unresponsive to standard medical therapy and required >100mg/day of morphine equivalence for pain control. Buccal swab was used to obtain test samples and 16 single nucleotide polymorphisms (SNP) were analyzed. The 4 categories of genetic markers included in the panel were receptor binding and activity (including dopamine, opioid, serotonin, and galanin receptors), neurotransmitter transporters, central nervous system (CNS) enzymes, and cytochrome P450 enzymes.
Results of the study found that genetic variations in the 3 dopamine receptors tested (DRD1, DRD4, DOR) were observed in 97 to 100% of patients included in the analysis. The study authors also reported that only 17 to 30% of patients were found to have genetic variations in the opioid receptors tested (OPRK1, OPRM1, and MUOR). Additionally, it was found that only the dopamine receptor markers had >90% genetic variation, suggesting that potent stimulation of the opioid receptors was required to obtain pain relief for these patients.
“These results suggest that since the dopaminergic pathway was defective, these pain patients relied on potent stimulation of their opioid receptors to obtain adequate pain relief,” the study authors add.
Based on the results of this study, some severe chronic pain patients may require higher doses of opioids for pain control due to genetic variations found in pain receptors. The study authors add, “These findings need to be investigated in other groups of pain patients who require high dose opioids to determine if dopaminergic defects are an underlying, genetic cause of high dose opioid requirements in some chronic pain patients.”
Read more of MPR's coverage of PAINWeek 2017 by visiting the conference page.
Tennant F, Vairavan R, Chang S, Priyam E, Connolly C. Multi Variant Genetic Panel in Pain Patients Who Take High Dose Opioids. Veract Intractable Pain Clinic. West Covina, CA, USA.