Percocet 5-325 mg and Oxycodone HCl IR 5 mg Are Equally Strong
Both medications contain the exact same amount of oxycodone (5 mg) and therefore provide identical opioid analgesic strength. The only difference is that Percocet includes 325 mg of acetaminophen, while oxycodone HCl IR 5 mg contains only the opioid component 1.
Understanding the Composition
- Percocet 5-325 mg contains 5 mg oxycodone combined with 325 mg acetaminophen in a fixed-dose combination formulation 2, 3
- Oxycodone HCl IR 5 mg contains only 5 mg oxycodone without any additional analgesic 1
- Both formulations are immediate-release (IR) preparations designed to provide rapid onset of analgesia 1, 4
Opioid Potency Equivalence
- The oxycodone component in both medications is pharmacologically identical, with the same morphine milligram equivalent (MME) conversion factor of 1.5, meaning each 5 mg dose equals 7.5 MME 5
- Oxycodone acts as an agonist at mu-, delta-, and kappa-opioid receptors with similar efficacy regardless of whether it is combined with acetaminophen 6
- The bioavailability of oxycodone is 60-87% for oral administration, and this is not significantly altered by the presence of acetaminophen in the formulation 1
The Acetaminophen Difference
- Percocet may provide superior overall analgesia due to the synergistic mechanism of action between oxycodone and acetaminophen, allowing for enhanced pain relief through complementary pathways 2, 3
- The fixed-dose combination demonstrates an opioid-sparing effect, meaning the addition of acetaminophen enhances the analgesic effect beyond what would be expected from either drug alone 3
- Studies show that oxycodone/acetaminophen combinations are effective for moderate-to-severe pain with the synergistic benefit of the acetaminophen component 4, 7
Clinical Implications for Pain Management
- For patients requiring only opioid analgesia or those who cannot take acetaminophen (hepatic impairment, maximum daily acetaminophen limits reached), oxycodone HCl IR 5 mg alone is appropriate 6
- For most patients with moderate pain, Percocet 5-325 mg may provide better overall pain control due to the multimodal analgesia from the combination 3, 4
- The acetaminophen dose must be monitored to avoid exceeding safe daily limits and potential hepatotoxicity, particularly if patients are taking other acetaminophen-containing products 6
Important Caveats
- Neither medication is "stronger" in terms of pure opioid content—both deliver exactly 5 mg of oxycodone 1
- The perceived difference in efficacy relates to the presence or absence of the acetaminophen component, not to differences in opioid potency 2, 3
- Individual patient response may vary based on genetics (CYP2D6 and CYP3A4 polymorphisms), tolerance, and pain type 1