Percocet 10mg is NOT Equal to Norco 10mg
No, Percocet (oxycodone) 10mg is approximately 50% more potent than Norco (hydrocodone) 10mg based on morphine milligram equivalent (MME) conversion factors. 1
Potency Comparison Based on MME Conversion
The CDC guideline provides standardized conversion factors that clearly demonstrate the difference in potency:
- Oxycodone (Percocet) has a conversion factor of 1.5, meaning 10mg oxycodone = 15 MME 1
- Hydrocodone (Norco) has a conversion factor of 1.0, meaning 10mg hydrocodone = 10 MME 1
Therefore, Percocet 10mg delivers 50% more opioid effect than Norco 10mg when comparing equivalent doses. 1
Clinical Equivalence Despite Different Potencies
While the MME calculations show oxycodone is more potent milligram-per-milligram, clinical trials demonstrate that when prescribed at appropriate equianalgesic doses, both medications provide comparable pain relief:
- Two prospective randomized controlled trials directly comparing oxycodone with hydrocodone combination products found them equal in pain relief, doses taken, global efficacy evaluations, and pain interference with work. 2
- The American College of Emergency Physicians states that equianalgesic doses of opioids are equally efficacious in relieving pain, regardless of their DEA classification. 2
Practical Dosing Implications
To achieve equivalent analgesia:
- Norco 10mg ≈ Percocet 6.7mg (based on the 1.5:1 ratio) 1
- Percocet 10mg ≈ Norco 15mg (inverse calculation) 1
The National Comprehensive Cancer Network notes that oxycodone has an equivalence ratio to morphine of approximately 1:1.5-2, while hydrocodone may be approximately equipotent with oral morphine. 3, 2
Clinical Decision-Making
The choice between these medications should be based on factors other than potency alone, including patient tolerance, side effect profile, and formulary considerations. 2
Key considerations:
- Individual patient response varies due to genetic polymorphisms affecting opioid metabolism (particularly CYP2D6 for hydrocodone). 3, 2
- Oxycodone causes somewhat less nausea, hallucinations, and pruritus than morphine. 4
- Both medications should be prescribed at the lowest practical dose for limited duration (e.g., 1 week) when used for acute pain. 2
Common Pitfall to Avoid
The perception that Percocet is "stronger" stems from its Schedule II classification versus hydrocodone's former Schedule III status, but this classification reflects abuse potential rather than analgesic efficacy. 2 Do not assume equal milligram doses provide equal analgesia—always use MME conversion factors when switching between opioids. 1