Opioid receptor response (OPRM1 A118G)

OPRM1 builds the main receptor that opioids and the body's own endorphins act on. A common variant (118G) can subtly change pain relief from opioids and the response to the alcohol-treatment drug naltrexone. It mainly matters in those specific situations.

Possible results

Typical opioid response. You have the common version of OPRM1, the main opioid receptor, so as far as this gene goes, your response to opioid pain medicines and to your own endorphins is in the typical range. This only matters if you ever need opioids or the alcohol-treatment drug naltrexone.

One 118G copy (OPRM1). You carry one copy of the OPRM1 118G variant, which can subtly reduce how much pain relief you get from opioids (sometimes needing a slightly higher dose) and may affect response to the alcohol-treatment drug naltrexone. It only matters in those specific situations.

Two 118G copies (OPRM1). You have two copies of the OPRM1 118G variant, more common in people of East Asian ancestry. It's linked to somewhat reduced opioid pain relief (possibly higher dose needs) and an altered response to naltrexone for alcohol use. This is informational and only relevant around those medications.

Evidence & sources

Across global populations, about 3% of people carry two copies of this variant, and about 73% carry none.

This variant appears in 6 published genetic studies: PubMed 32492095 · PubMed 35879402 · PubMed 36171425 · PubMed 36207451 · PubMed 37156939 · PubMed 37250466.

Related

Abacavir hypersensitivity (HLA-B*57:01) · Drug acetylation speed (NAT2) · Fluoropyrimidine (5-FU) toxicity risk · Hepatitis C treatment response (IL28B) · Statin-induced myopathy risk · Tacrolimus metabolism (CYP3A5 gene) · Thiopurine metabolism (TPMT and NUDT15 genes)