Oxycodone vs Fentanyl
## Overview
Oxycodone and fentanyl serve overlapping but distinct clinical roles. Oxycodone is primarily an oral opioid for moderate-to-severe chronic pain; fentanyl is available via transdermal, transmucosal, and IV routes and is preferred in CKD and for breakthrough cancer pain.
## Mechanism of Action
Both are full mu-opioid receptor agonists. Fentanyl's extreme lipophilicity creates very different absorption characteristics from oxycodone.
## Pharmacokinetics
Oxycodone: oral bioavailability 60–87%, CYP-dependent metabolism. Fentanyl: transdermal delivery results in skin depot, 12–24 h onset, ~72-h dosing interval; no active metabolites (important CKD advantage).
## Clinical Selection
Stable chronic cancer pain with established opioid dose → fentanyl patch. Oxycodone ER is also appropriate here. Fentanyl buccal/SL used for breakthrough cancer pain. IV fentanyl for procedural analgesia or ICU. Oxycodone oral most common for outpatient moderate-to-severe pain.
## Key Takeaways
- Fentanyl: no active metabolites (preferred in CKD/ESRD), multiple routes
- Oxycodone: oral preferred route, higher bioavailability than morphine
- Fentanyl patch requires stable dose before initiation
الخلاصة
Fentanyl is preferred in CKD/ESRD and for rapid-onset breakthrough cancer pain. Oxycodone is the standard oral opioid for chronic moderate-to-severe pain management when renal function is adequate. Both require careful titration and monitoring.