Opioid comparison chart covering defensible IV board-style equipotent doses, onset, duration, metabolism, and context-sensitive half-time concepts for anesthesia review.
Review the core table first, then launch practice to convert recognition into faster recall.
| Drug | IV equipotent dose | Onset (min) | Duration | Metabolism | Key pearl |
|---|---|---|---|---|---|
| Morphine | 10 mg | 5-10 | 3-4 h | Hepatic glucuronidation to M3G and M6G; renal excretion of metabolites | Slower onset, histamine release, active metabolites matter in renal failure |
| Fentanyl | 100 mcg | 1-2 | 30-60 min after bolus | Hepatic CYP-mediated metabolism | Very lipophilic; context-sensitive half-time rises with prolonged infusion |
| Sufentanil | 10 mcg | 1-3 | 20-45 min after bolus | Hepatic metabolism | Roughly 5-10× more potent than fentanyl |
| Hydromorphone | 1.5 mg | 5 | 2-4 h | Hepatic glucuronidation | Potent morphine alternative with less histamine release |
| Meperidine | 75-100 mg | 3-5 | 2-4 h | Hepatic metabolism to normeperidine | Normeperidine is neurotoxic and meperidine has serotonergic activity |
Remifentanil is intentionally not placed in the fixed IV equipotency table above. Its ultra-short context-sensitive half-time and organ-independent esterase metabolism make postoperative or cross-opioid “equivalent dose” teaching too context-dependent to present as a clean board-style conversion. In this module, remifentanil is kept as a pharmacokinetic and context-sensitive-half-time concept instead.
This tool is for educational purposes only. Always verify clinical values against current authoritative sources before patient care.