A 32-year-old man from Delhi presents to the psychiatry outpatient department with a 6-year history of heroin use. He reports daily use, spending ₹2,000–3,000 per day. Over the past 3 months, he has attempted to quit twice but experienced severe withdrawal symptoms (body aches, insomnia, anxiety, sweating) within 12–18 hours of last use, forcing him to relapse. He denies any other substance use or psychiatric comorbidity. On examination, he appears anxious and restless. Urine drug screen is positive for opioids. He is motivated for treatment and asks about pharmacotherapy options that can reduce craving and prevent relapse. Which of the following is the most appropriate first-line maintenance pharmacotherapy for this patient?

Explanation

## Opioid Use Disorder: Maintenance Pharmacotherapy ### Clinical Context This patient has opioid use disorder (OUD) with: - Chronic daily heroin use (6 years) - Multiple relapse attempts - Severe withdrawal syndrome (body aches, insomnia, anxiety, sweating within 12–18 hours) - High motivation for treatment **Key Point:** The timeline of withdrawal onset (12–18 hours) is classic for short-acting opioids like heroin, confirming physical dependence. ### First-Line Maintenance Options for OUD | Agent | Mechanism | Onset | Duration | Withdrawal Risk | Overdose Risk | First-Line? | |-------|-----------|-------|----------|-----------------|---------------|-------------| | **Buprenorphine** | Partial μ-opioid agonist | 30–60 min | 24–72 hrs | Mild | Very low | **YES** | | **Methadone** | Full μ-opioid agonist | 30–60 min | 24–36 hrs | Severe | High | YES (alternative) | | Naltrexone | μ-opioid antagonist | 30 min | 24–72 hrs | Precipitated WD | None | No (3rd-line) | | Clonidine | α~2~-adrenergic agonist | — | — | Adjunct only | None | No (adjunct) | ### Why Buprenorphine Is Preferred **High-Yield:** Buprenorphine is now the **preferred first-line** agent in most guidelines (WHO, SAMHSA, NICE) because: 1. **Partial agonist activity** → lower overdose risk than methadone 2. **Ceiling effect on respiratory depression** → safer in overdose 3. **Milder withdrawal syndrome** if discontinued 4. **Flexible dosing** (sublingual, implant, injection formulations) 5. **Can be prescribed in office-based settings** (unlike methadone, which requires specialized clinics in many countries) 6. **Lower abuse potential** compared to methadone **Clinical Pearl:** Buprenorphine's partial agonist profile means it: - Relieves withdrawal symptoms and cravings - Does NOT produce euphoria (reduces reinforcement) - Has a "ceiling effect" on respiratory depression (safer than full agonists) ### Dosing in This Patient - **Induction:** 4–8 mg/day (sublingual), titrated over 3–7 days - **Maintenance:** 12–16 mg/day (range 4–24 mg/day) - Often combined with naloxone (buprenorphine/naloxone 4:1 ratio) to discourage IV misuse **Mnemonic:** **BUPRE** = **B**est **U**se for **P**artial **R**eceptor **E**ffect ### Expected Outcomes - Reduction in illicit opioid use within 1–2 weeks - Improved treatment retention (>70% at 6 months) - Reduced craving and withdrawal symptoms - Lower relapse risk compared to abstinence-only approaches [cite:Harrison 21e Ch 474]