Exploratory study on association of single-nucleotide polymorphisms with hydromorphone analgesia in ED

The objective of this study is to provide information on distribution of important single-nucleotide polymorphisms (SNPs) and evaluate their associations with clinical response to intravenous hydromorphone in emergency department.

A prospective exploratory study was performed. A convenience sample of adult emergency department patients with acute pain deemed to require intravenous opioids received 1 mg of intravenous hydromorphone. Primary outcome was pain score (numeric rating scale, NRS) reduction between baseline and 30 minutes after medication administration. Secondary outcomes were pain relief, patient satisfaction with analgesia, desire for more analgesics, and side effects (nausea, vomiting, and pruritis). Single-nucleotide polymorphisms in OPRM1 gene (opioid receptor, A118G), ABCB1 gene (opioid transporter, C3435T), COMT gene (pain sensitivity, G1947A), and UGT2B7 gene (opioid metabolism, -G840A) were tested. We used Kruskal-Wallis test to compare the primary outcome and χ(2) test (or Fisher test) to compare the secondary outcomes among patients carrying different SNPs.

One thousand four hundred thirty-eight patients were screened, and 163 patients were enrolled in the study. The mean age was 39 years. Sixty-three percent were female, 58% were Hispanic, and 67% had pain located in abdomen. The median pain NRS reduction at 30 minutes was 5 (interquartile range, 3-8). There was no difference in pain NRS reduction among patients carrying different SNPs. Secondary outcome analysis revealed statistically significant associations between patient satisfaction with treatment and OPRM1 and between nausea and UGT2B7.

This exploratory study did not show a significant difference in pain NRS reduction among patients carrying different SNPs. Patient satisfaction with analgesia and nausea were statistically significantly associated with OPRM1 and UGT2B7, respectively.