Key Differences Between Norco and Percocet
Norco (hydrocodone/acetaminophen) and Percocet (oxycodone/acetaminophen) differ primarily in their opioid component and regulatory classification, with oxycodone being approximately 1.5 times more potent than hydrocodone on a milligram-to-milligram basis, though clinical trials demonstrate equivalent pain relief at equianalgesic doses. 1
Opioid Component and Potency
- Norco contains hydrocodone (typically 5-10 mg) combined with acetaminophen (now limited to 325 mg per tablet) 2
- Percocet contains oxycodone (typically 5-10 mg) combined with acetaminophen (325 mg per tablet) 2
- Oxycodone has a morphine milligram equivalent (MME) conversion factor of 1.5, while hydrocodone has a conversion factor of 1.0, making oxycodone approximately 50% more potent per milligram 1
Regulatory Classification
Historical Classification (Pre-2014)
- Hydrocodone combination products (Norco, Vicodin, Lortab) were Schedule III controlled substances when the guideline was published 2
- Oxycodone combination products (Percocet) have always been Schedule II controlled substances 2
Current Status
- Both are now Schedule II controlled substances, though the evidence reflects the historical difference in abuse potential perception 2
Dosing and Administration
- Both medications are dosed every 4-6 hours as needed for acute pain 2
- Starting doses range from 5-15 mg of the opioid component for both agents 2
- Acetaminophen content is now limited to 325 mg or less per pill in both formulations 2
Clinical Efficacy
At equianalgesic doses, hydrocodone and oxycodone combinations demonstrate equivalent pain relief with no clinically significant differences. 2, 3
- A prospective randomized trial comparing oxycodone 5 mg/acetaminophen with hydrocodone 7.5 mg/acetaminophen found no differences in pain relief, doses taken, or global evaluations of efficacy 2
- A 2015 ED study comparing oxycodone/acetaminophen 5 mg/325 mg versus hydrocodone/acetaminophen 5 mg/325 mg showed both reduced pain scores by approximately 50% with no statistically significant difference (mean decrease 4.4 vs 4.0 NRS units, difference 0.4 units) 3
Safety Profile
- Both medications carry similar risks of opioid-related adverse effects including nausea, vomiting, constipation, and respiratory depression 4
- Acetaminophen hepatotoxicity risk is identical since both contain the same amount (325 mg) 2, 5
- Maximum daily acetaminophen dose of 4000 mg must be monitored with either medication 2
Clinical Pitfalls
- Do not assume Percocet is "stronger" simply because it is Schedule II - at equianalgesic doses, efficacy is equivalent 2
- Account for all acetaminophen sources in the patient's regimen to avoid exceeding 4000 mg daily 5
- Neither medication should be prescribed routinely for chronic pain or acute exacerbations of chronic non-cancer pain 2
- Limit prescriptions to the lowest practical dose for limited duration (e.g., 1 week) when prescribed for acute pain 2