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Clinical Atlas Prestige · Evidence-first

Psych VivasAddiction psychiatry — substance use disorders

Psych Vivas · Addiction psychiatry — substance use disorders

Opioid substitution therapy and withdrawal — structured clinical viva

Fellowship viva on methadone–buprenorphine transfer, QTc, precipitated withdrawal, naltrexone timing, and retention mortality.

clinical
On this page & tools

Target exams

FRANZCPMRCPsychABPNMD-DNB

Target exams

FRANZCPMRCPsychABPNMD-DNB
Prompt
You are the addiction psychiatry registrar. A 38-year-old man on methadone 100 mg wants transfer to buprenorphine 'because methadone is heart poison' after reading online. Last ECG QTc 465 ms. He missed one dose yesterday, last heroin use 4 days ago (denies today), and asks whether he can start naltrexone implant this week instead. Discuss assessment, COWS role, transfer risks, cardiac framing, and evidence-based options.

Interpretation

Reveal interpretation

This is a transfer and risk-communication viva, not an automatic switch. Methadone 100 mg is a substantial full-agonist dose; jumping to buprenorphine without adequate withdrawal precipitates severe withdrawal. One missed dose plus remote heroin use does not equal a safe naltrexone start this week.[2][4]

QTc 465 ms needs context (sex-specific cut-offs, electrolytes, symptoms, interacting drugs). Krantz et al. frame systematic QTc screening — borderline values prompt review, dose consideration, and shared decisions, not necessarily panic cessation without a plan.[1]

Buprenorphine transfer usually requires specialist protocol: reduce methadone, wait for objective withdrawal (COWS), then induct carefully. Benefits may include partial-agonist respiratory ceiling and take-home logistics — not zero risk.[4][6]

Naltrexone implant/XR requires completed detox and is not a one-week “cure.” X:BOT highlights induction difficulty versus buprenorphine–naloxone. Implants are jurisdiction-specific.[3]

Frame retention mortality: leaving OAT impulsively for unproven online plans raises overdose risk.[5]

Key points

Transfers respect receptor occupancy

High-dose methadone to buprenorphine needs timed withdrawal — precipitated withdrawal is preventable.

QTc is risk–benefit, not slogan

Screen, correct electrolytes, review interactions; do not abandon OAT without a safer alternative plan.

Antagonists need a clean opioid-free window

Naltrexone this week after recent methadone is a precipitated-withdrawal trap.
[1] [2] [3] [4] [5]

References

  1. [1]Krantz MJ, Martin J, Stimmel B, et al. QTc interval screening in methadone treatment Ann Intern Med, 2009.PMID 19153406
  2. [2]Wesson DR, Ling W The Clinical Opiate Withdrawal Scale (COWS) J Psychoactive Drugs, 2003.PMID 12924748
  3. [3]Lee JD, Nunes EV, Novo P, et al. Comparative effectiveness of extended-release naltrexone versus buprenorphine-naloxone for opioid relapse prevention (X:BOT) Lancet, 2018.PMID 29150198
  4. [4]American Society of Addiction Medicine The ASAM National Practice Guideline for the Treatment of Opioid Use Disorder: 2020 Focused Update J Addict Med, 2020.PMID 32511106
  5. [5]Sordo L, Barrio G, Bravo MJ, et al. Mortality risk during and after opioid substitution treatment BMJ, 2017.PMID 28446428
  6. [6]Mattick RP, Breen C, Kimber J, Davoli M Buprenorphine maintenance versus placebo or methadone maintenance for opioid dependence Cochrane Database Syst Rev, 2014.PMID 24500948