Nalorphine Stats & Data
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DrugBankDescription
Nalorphine is a mixed opioid agonist–antagonist. It acts at two opioid receptors—at the mu receptor it has antagonistic effects, and at the kappa receptors it exerts high-efficacy agonistic characteristics. It is used to reverse opioid overdose and (starting in the 1950s) in a challenge test to determine opioid dependence.
Indication
Used to reverse opioid overdose.
Measured Affinities
Guide to PHARMACOLOGYMeasured binding and functional data for nalorphine, curated by the IUPHAR/BPS Guide to PHARMACOLOGY. Each row cites the paper it came from. Lower concentrations mean tighter binding — a value in the sub-nanomolar range indicates a very potent interaction.
| Target | Action | Measure | Value | Concentration | Species | Source |
|---|---|---|---|---|---|---|
| μ receptor OPRM1 | Antagonist | pKi | 8.9 | 1.26 nM | Human | PMID 9686407 |
| δ receptor OPRD1 | Partial agonist | pKi | 7.4 | 39.81 nM | Human | PMID 9686407 |
| κ receptor OPRK1 | Partial agonist | pKi | — | — | Human | — |
Reading this. pKi, pEC50 and pIC50 are negative log molar values, so a higher number means a tighter interaction; the concentration column converts them for you. Values from non-human species are laboratory measurements and do not translate directly to human effect. Receptor affinity is not a dose — it describes what a molecule binds, not how much of it is safe to take.
Receptor data from the IUPHAR/BPS Guide to PHARMACOLOGY (v2026.2), licensed CC BY-SA 4.0. Matched to this substance by InChIKey.