Opioid substitution therapy and withdrawal — structured clinical viva

Frame it as a transfer and risk conversation. Retention in methadone and buprenorphine treatment is associated with substantial reductions in all-cause and overdose mortality, and the time immediately after leaving treatment carries particularly increased mortality risk.^[5] In the New South Wales cohort, mortality was higher out of treatment, particularly during the first weeks, and mortality was similarly reduced whether patients were receiving methadone or buprenorphine.^[12]

The QTc of 465 ms. The Krantz panel recommends informing patients of arrhythmia risk and asking about structural heart disease, arrhythmia and syncope. Additional ECGs are recommended if the methadone dose exceeds 100 mg/d. If QTc is above 450 but below 500 ms, discuss risks and benefits and monitor more often; above 500 ms, consider discontinuing or reducing methadone, removing contributing factors such as drugs that promote hypokalaemia, or an alternative therapy.^[1] The methadone label reports QT prolongation and torsades de pointes, including at doses commonly used for maintenance treatment.^[8] The buprenorphine/naloxone label reports QT prolongation of 15 msec or less in thorough QT studies, and judges buprenorphine unlikely to be pro-arrhythmic when used alone in patients without risk factors.^[9]

Transfer to buprenorphine. Buprenorphine, a partial agonist, can precipitate withdrawal in highly dependent patients who are not yet in withdrawal, and the summed COWS score of eleven withdrawal signs or symptoms assesses the level of withdrawal.^[2] Patients dependent on methadone may be more susceptible to precipitated and prolonged withdrawal during induction than those on short-acting opioids, and the buprenorphine/naloxone label recommends buprenorphine monotherapy for them on Days 1 and 2. For induction with the buprenorphine/naloxone film itself, the label advises waiting until objective and clear signs of withdrawal are evident.^[9]

What he gives up. With flexible dosing, methadone retains more people in treatment than buprenorphine.^[6]

Naltrexone this week. An opioid-free interval of at least 7 to 10 days is recommended before extended-release naltrexone, to avoid withdrawal severe enough to need hospitalisation; the label contraindicates it in current physiological opioid dependence.^[10] In X:BOT, fewer participants initiated extended-release naltrexone than buprenorphine-naloxone (72% versus 94%), and among those successfully inducted, 24-week relapse was similar.^[3]