Abstract TRV130 is a G protein‐biased ligand at the µ‐opioid receptor. In preclinical studies it was potently analgesic while causing less respiratory depression and gastrointestinal dysfunction than morphine, suggesting unique benefits in acute pain management. A first‐in‐human study was conducted with ascending doses of TRV130 to explore its tolerability, pharmacokinetics, and pharmacodynamics in healthy volunteers. TRV130 was well‐tolerated over the dose range 0.15 to 7 mg administered intravenously over 1 hour. TRV130 geometric mean exposure and C max were dose‐linear, with AUC 0–inf of 2.52 to 205.97 ng h/mL and C max of 1.04 to 102.36 ng/mL across the dose range tested, with half‐life of 1.6–2.7 hours. A 1.5 mg dose of TRV130 was also well‐tolerated when administered as 30, 15, 5, and 1 minute infusions. TRV130 pharmacokinetics were modestly affected by CYP2D6 phenotype: clearance was reduced by 53% in CYP2D6 poor metabolizers.TRV130 caused dose‐ and exposure‐related pupil constriction, confirming central compartment µ‐opioid receptor engagement. Marked pupil constriction was noted at 2.2, 4, and 7 mg doses. Nausea and vomiting observed at the 7 mg dose limited further dose escalation. These findings suggest that TRV130 may have a broad margin between doses causing µ‐opioid receptor‐mediated pharmacology and doses causing µ‐opioid receptor‐mediated intolerance.