Brief Report: Is once daily enough? Assessing the impact of timing of methadone dose on pain sensitivity via quantitative sensory testing in persons with opioid use disorder

BACKGROUND AND OBJECTIVES: Once-daily methadone dosing for opioid use disorder (OUD) may leave periods of inadequate analgesia. We tested whether experimental pain sensitivity differs across the inter-dose interval. METHODS: Twenty-five adults (52% female, 43.12 years old) with OUD receiving stable once-daily methadone completed thermal quantitative sensory testing at early post-dose and pre-dose. RESULTS: Heat pain threshold (MD -3.75°C; g = -0.78; p < .001) and tolerance (MD -0.92°C; g = -0.49; p = .018) were lower at pre-dose. Temporal summation and conditioned pain modulation did not differ. DISCUSSION AND CONCLUSIONS: Pain sensitivity increased pre-dose, consistent with a hyperalgesic window. SCIENTIFIC SIGNIFICANCE: Preliminary experimental evidence that once-daily methadone may contribute to cyclical hyperalgesia in persons with OUD.