Table 2 Summary and general recommendations.
IV naloxone | PO naltrexone | |
|---|---|---|
Properties | ||
Time-to-peak blockade | 25 min | Likely 1–2 h |
Blockade half-life | 110 min | 72 h |
MOR:DOR:KOR affinity ratio | 1:41:8 | 1:79:2 |
Recommendations | ||
Recommended doses for full (>90%) MOR blockade | 0.01–0.15 mg/kg (bolus) | 50 mg |
Recommended delay between administration and outcome assessment | Minimum 15 min with 0.01 mg/kg (bolus). Minimum 10 min with 0.10–0.15 mg/kg (bolus). | Minimum 1–2 h |
Duration of full (>90%) MOR blockade | ~30 min with 0.01 mg/kg (bolus). ~65 min with 0.10–0.15 mg/kg (bolus). | At least 49 h with 50 mg |
Concurrent DOR blockade | Low (11–12%) with 0.01 mg/kg (bolus). Medium-to-high (48–74%) with 0.10–0.15 mg/kg (bolus). | Low (10%) with 50 mg |
Concurrent KOR blockade | Medium (39–43%) with 0.01 mg/kg (bolus). High-to-full (78–100%) with 0.10–0.15 mg/kg (bolus). | High (82%) with 50 mg |
Recommended intersession interval for complete washout | Minimum 9 h | Minimum 15 days |
Recommended dose for full opioid receptor blockade (MOR, DOR and KOR) | 1.0 mg/kg (bolus) | None (impractical due to the low DOR affinity) |
Cost | ||
Cost of druga | One 0.4 mg/ml vial or ampoule: 4.58–7.07 USD | One 50 mg tablet: 4.28–9.72 USD |
Cost of full MOR blockade with bolus dose (assuming the participant weighs 70 kg)a | Full MOR blockade for 65 min with 0.1 mg/kg: ~100 USD. Full MOR blockade for 30 min with 0.01 mg/kg: ~10 USD. | Full MOR blockade for up to 49 h with 50 mg: ~4–10 USD |
