Severe Early-Onset Withdrawal Following Intentional Use of Mitragynine Pseudoindoxyl: A Case Report and Emerging Clinical Considerations.

Kratom is increasingly used in the United States for pain, mood, anxiety, and opioid substitution. Traditional kratom produces mild, delayed withdrawal, but semisynthetic derivatives such as mitragynine pseudoindoxyl (MP) are highly potent μ-opioid receptor agonists with δ-opioid receptor antagonism, leading to rapid-onset, full-spectrum opioid-like withdrawal. We describe a 34-year-old man with long-term remission from heroin use disorder who presented with suicidal ideation and severe opioid-like withdrawal despite no recent opioid use. He progressed from powdered kratom to 7-hydroxymitragynine tablets and then MP tablets, averaging nine 20 mg doses daily, including nocturnal use. On presentation, he exhibited chills, tremors, diaphoresis, gastrointestinal distress, restlessness, with a Clinical Opiate Withdrawal Scale score of 31, blood pressure 168/107 mmHg, and heart rate 115 bpm. Supportive management with clonidine, hydroxyzine, gabapentin, loperamide, and antiemetics over 72-96 hours led to symptom resolution. Naltrexone, including a Vivitrol injection, was initiated without precipitating withdrawal, and the patient remained abstinent at one-month follow-up, despite a brief noneuphoric lapse. This case highlights MP as an emerging high-potency kratom derivative that poses unique diagnostic and management challenges. Clinicians should recognize its severe withdrawal profile, the limitations of standard toxicology, and the potential role of naltrexone in relapse prevention once an opioid-free interval is established.