Duration of Action: Norco vs Percocet
Both Norco (hydrocodone/acetaminophen) and Percocet (oxycodone/acetaminophen) have essentially the same duration of action, lasting 4-6 hours, with no clinically meaningful difference in how long their pain relief effects persist. 1
Pharmacokinetic Profile
Both medications are classified as short-acting oral opioid formulations with identical dosing intervals:
- Hydrocodone/APAP (Norco): Dosed every 4-6 hours as needed 1
- Oxycodone/APAP (Percocet): Dosed every 4-6 hours as needed 1
The recommended dosing schedule of Q4-6h PRN for both agents reflects their equivalent duration of analgesic effect 1.
Comparative Efficacy Evidence
Clinical trials demonstrate no difference in duration of pain relief between these agents:
- A 2015 randomized controlled trial found that both oxycodone/acetaminophen (5mg/325mg) and hydrocodone/acetaminophen (5mg/325mg) reduced pain scores by approximately 50% over 2 hours, with no statistically significant difference in analgesic efficacy 2
- A 2005 double-blind RCT comparing these medications for acute fracture pain showed pain relief from baseline to 60 minutes was similar between groups, with no difference at either 30 or 60 minutes 3
- Multiple prospective randomized controlled trials comparing oxycodone with hydrocodone combination products found them to be equal in pain relief 1
Important Clinical Distinctions
While duration is equivalent, there are other differences to consider:
Potency differences:
- Oxycodone has better systemic bioavailability (60-90%) compared to hydrocodone, making the equianalgesic oral dose of oxycodone approximately half to two-thirds that of oral morphine 1
- Hydrocodone may be approximately equipotent with oral morphine, though equivalence data are not well substantiated 1
Side effect profiles:
- Hydrocodone showed a higher incidence of constipation (21% vs 0%) compared to oxycodone in one study 3
- Otherwise, adverse effect profiles are similar between the two agents 2, 3
Common Pitfall to Avoid
Do not confuse immediate-release formulations with extended-release products. Long-acting or extended-release formulations (such as OxyContin) are indicated for chronic pain in opioid-tolerant patients only and should never be used for acute pain 1. The immediate-release formulations of both Norco and Percocet discussed here are appropriate only for acute pain management with 4-6 hour dosing intervals 1.