5th Edition of Addiction World Conference 2026

Abstract

Background/Significance
Behavioral dysregulation and anxiety are common consultation-liaison (C-L) psychiatry referrals in medically hospitalized patients with opioid use disorder (OUD). Differentiating primary psychiatric pathology from undertreated opioid withdrawal is challenging during methadone-to-buprenorphine transitions, particularly when short-acting opioids are used for acute pain. Fear of precipitated withdrawal may delay dose optimization and lead to misattribution of withdrawal-related distress to psychiatric pathology.

Case
A 40-year-old man with severe OUD and recent fentanyl exposure was admitted for septic thrombophlebitis of the right upper extremity requiring thrombectomy and IV antibiotics. Methadone 40 mg daily was started on hospital day (HD) 1 for opioid withdrawal, but he required additional oxycodone for postoperative pain. By HD 3–4, he developed agitation, anxiety, IV-line tampering, and provocative suicidal statements, prompting C-L consultation.

While COWS scores ranged from 6–10, the C-L team determined symptoms reflected undertreated withdrawal rather than primary psychiatric pathology. Methadone was discontinued, and buprenorphine/naloxone was initiated 48 hours later at 4 mg, with continued oxycodone for pain. No precipitated withdrawal occurred. A symptom-triggered induction began with 2 mg, with reassessment every 3 hours and additional 2 mg doses for COWS ≥12 or cravings (max 24 mg/day). On subsequent days, the prior total dose was consolidated (max single dose 12 mg) and transitioned to BID–TID dosing. The patient was ultimately titrated to 24–28 mg/day in divided doses while short-acting opioids were continued for acute pain.

During titration of buprenorphine, agitation persisted. Buprenorphine was increased to 28 mg/day by HD 10. As doses exceeded 16 mg/day, cravings, agitation, and engagement improved, with declining oxycodone use. Psychiatric stabilization was achieved prior to discharge planning.

Discussion
This case illustrates that subtherapeutic methadone and low-dose buprenorphine may provide insufficient receptor coverage in patients with high opioid tolerance (Huhn, 2020). Mild COWS scores did not reflect adequate neurobiological stabilization. Behavioral dysregulation initially attributed to psychiatric pathology resolved only with higher-dose buprenorphine, demonstrating a clear dose-response relationship.

Buprenorphine was safely initiated despite recent methadone exposure and ongoing short-acting opioid administration. Fear of precipitated withdrawal may contribute to overly conservative dosing and prolonged undertreatment. These findings support careful but assertive titration strategies in medically complex patients.

Conclusion/Implications
In medically hospitalized patients with severe OUD, agitation and anxiety may reflect undertreated withdrawal rather than primary psychiatric illness. Buprenorphine can be safely initiated after recent opioid exposure and in the presence of short-acting opioids when carefully monitored (SAMHSA, 2024). Adequate dose titration—often exceeding 16 mg/day in high-tolerance patients—may clarify diagnostic ambiguity, reduce behavioral conflict, and improve patient engagement. C-L psychiatrists play a critical role in recognizing withdrawal-related behavioral dysregulation and facilitating appropriate partial agonist dosing.