Raw research findings for this medication. Mostly single studies, not curated or confirmed robust.
Butorphanol is a mixed opioid: it activates kappa opioid receptors and only partly activates mu receptors, so its effect on breathing levels off at higher doses. It is used by injection for pain during labour and before surgery, and as a nasal spray for migraine and other acute pain. It was sold as Stadol.
Butorphanol is broken down in the liver. The gene studies on it, mostly from China on pain after surgery, looked at the kappa opioid receptor gene OPRK1, the mu receptor gene OPRM1 and COMT for how much pain relief people needed. The findings come from a few studies, and there is no CPIC or DPWG guideline.
Every published finding on gene variants and Butorphanol. Upload your DNA file to see which of these rows apply to you.
PharmGKB weighs all studies of a variant and rates how strong the evidence is, from 1A (strongest) to 4.
OPRK1 rs702764: Level 3. Efficacy. 1.
COMT rs4633: Level 3. Efficacy. 1.
COMT rs6269: Level 3. Efficacy. 1.
Studies of how well it worked in people carrying a variant.
Study findings and evidence levels: PharmGKB (CC BY-SA 4.0). Guidelines: CPIC and DPWG, as bundled in PharmCAT. Most studies were done mainly in people of European ancestry.
More drugs from the same category
Not a prescribing recommendation. This page is educational information about pharmacogenomic research and clinical guidelines - it is not medical or dosing advice, and not a prediction of how any medication will work for you. Never start, stop, or change a medication or dose based on it; talk to your doctor or pharmacist, who can order clinical-grade testing if appropriate.
Content updated September 2026.
ReadYourDNA provides educational interpretation of DNA data you already have. It is not diagnostic, not a substitute for professional medical advice, diagnosis, or treatment, and is not intended to diagnose, treat, cure, or prevent any disease. Talk to a clinician before acting on any result.
Raw DNA Data Reports for 23andMe & AncestryDNA · About ReadYourDNA · FAQ · Methodology & Science · Pricing · Support and complaints · Legal & Contact · Health Traits · Pharmacogenomics · Carrier Status · Variant Explorer · The Human Karyotype · Privacy Policy · Terms of Service · Accessibility · Consumer Health Data Privacy · Your Privacy Choices · Editorial Standards · Your Data, Checkable · Sample Report · ReadYourDNA and Promethease compared · What is inside a 23andMe raw data file · What is inside an AncestryDNA raw data file · What a chatbot can and cannot do with your raw DNA file · Where a raw DNA file can still be uploaded in 2026
Written, maintained and operated by Martin Pechhacker, sole proprietor, Vienna, Austria. Trade register GISA 40064420. support@readyourdna.com