SR-17018 vs Other Kappa-Opioid Agonists
How SR-17018's biased agonist profile compares to traditional KOR agonists and to classical mu-opioid analgesics like morphine. A reference for researchers selecting tool compounds.
Choosing the right kappa-opioid receptor (KOR) agonist for a study depends on the mechanistic question being asked. Traditional KOR agonists like U-50,488 and salvinorin A produce robust analgesia but trigger β-arrestin signaling that drives dysphoria, sedation, and rapid tolerance. SR-17018 was designed to dissociate these effects via functional selectivity, preferentially activating G-protein cascades while sparing β-arrestin recruitment.
The table below summarizes the most experimentally-relevant differences. Cells marked with a check indicate "yes" or "favorable", an X indicates "no" or "absent", and a dash indicates partial or context-dependent effects.
| Property | SR-17018 | U-50,488 | Salvinorin A | Nalfurafine | Morphine (MOR) |
|---|---|---|---|---|---|
| Signaling bias | G-protein biased (>100×) | Balanced | Arrestin-biased | G-protein biased | Balanced |
| Receptor selectivity | Highly KOR-selective | KOR-selective | Highly KOR-selective | KOR-selective | MOR-selective |
| Produces analgesia | |||||
| Causes dysphoria | |||||
| Causes sedation | |||||
| Tolerance development | Minimal | High | Rapid | Low | High |
| Abuse liability |
Why SR-17018 stands out
SR-17018 is currently the most-studied G-protein-biased KOR agonist with a quantified bias factor exceeding 100-fold. In preclinical models, it preserves the analgesic and anti-pruritic efficacy characteristic of KOR activation while avoiding the arrestin-mediated side effects (dysphoria, sedation, tolerance) that historically blocked KOR therapeutics from clinical translation.
Read the deep-dive on biased agonism →When to choose SR-17018
- • Tolerance and chronic-dosing studies
- • Models requiring KOR analgesia without sedation
- • Stress, addiction, and reward-circuit research
- • Comparator studies against U-50,488 or salvinorin A
Verify the science
All claims on this comparison page are sourced from peer-reviewed literature. See our research library for full citations to Brust et al. (2016), Zamarripa et al. (2020), Huskinson et al. (2022), and other primary sources.