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Potency ratio of hydromorphone and diacetylmorphine in substitution treatment for long-term opioid dependency

Eugenia Oviedo-Joekes, PhD, David C. Marsh, MD, Daphne Guh, MSc, Suzanne Brissette, MD, Martin T. Schechter, MD, PhD


Background: Data on conversion ratios for switching opioids in substitution treatment are limited.
Methods: Data were obtained from a randomized controlled trial among long-term opioid-dependent patients conducted in Vancouver and Montreal, Canada. Patients received diacetylmorphine (n 115) or hydromorphone (n 25) on a double-blind basis, on a 1:3 potency ratio with individually adjusted dosage, both injectable.
Results: Average daily dosages of hydromorphone and diacetylmorphine prescribed were 212.6 mg and 454.0 mg, respectively; potency ratio was 1:2.0-2.2 at different dose ranges.
Conclusions: Studies using hydromorphone as a diacetylmorphine equivalent should consider the ratio found in this study to achieve equipotency and maintain the blinding.


opioid dependency, hydromorphone, diacetylmorphine, substitution treatment with opioid agonists, equipotency

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