What codeine and acetaminophen dose is equivalent to a tablet containing 10 mg hydrocodone and 325 mg acetaminophen?

Opioid Dose Conversion: Hydrocodone to Codeine

A single tablet of hydrocodone 10 mg/acetaminophen 325 mg is approximately equivalent to codeine 60-67 mg/acetaminophen 325 mg, which would require 2 tablets of the standard codeine/acetaminophen 30/300 mg formulation.

Calculation Using MME Conversion

Using the CDC's morphine milligram equivalent (MME) conversion factors, the calculation is straightforward 1:

• Hydrocodone 10 mg converts to 10 MME (conversion factor = 1.0) 1
• Codeine has a conversion factor of 0.15 1
• To achieve 10 MME with codeine: 10 MME ÷ 0.15 = 66.7 mg of codeine

This means hydrocodone 10 mg is approximately 6.7 times more potent than codeine on an MME basis 1.

Practical Dosing Recommendation

For the acetaminophen component:

• The 325 mg acetaminophen in the hydrocodone formulation matches standard codeine/acetaminophen combinations 2

Standard available formulation:

• Codeine/acetaminophen typically comes as 30 mg/300 mg tablets 3, 4
• Two tablets (codeine 60 mg/acetaminophen 600 mg) would provide the closest equivalent 3, 4

Critical Cautions for Opioid Conversion

The CDC explicitly warns against using MME calculations for direct opioid-to-opioid conversions 1. Key considerations include:

• Equianalgesic conversions are estimates only and cannot account for individual variability in genetics and pharmacokinetics 1
• When converting between opioids, the new opioid should be dosed at a substantially lower dose than the calculated MME to avoid overdose due to incomplete cross-tolerance 1
• Individual patient factors significantly affect opioid response 1

Clinical Efficacy Evidence

Research demonstrates that these medications may not be as different clinically as their MME ratios suggest:

• A 2014 emergency department study found no clinically important difference between hydrocodone/acetaminophen 5/500 mg and codeine/acetaminophen 30/300 mg for acute extremity pain, with both reducing pain by approximately 50% 3
• A 2017 JAMA trial showed hydrocodone/acetaminophen 5/325 mg and codeine/acetaminophen 30/300 mg had similar pain reduction at 2 hours (3.5 vs 3.9 NRS units respectively) 5
• However, a 1991 study found hydrocodone had significantly fewer treatment failures and fewer CNS side effects compared to codeine despite similar pain scores 6

Safety Considerations

Starting with a conservative approach is warranted:

• Begin with codeine 30-60 mg (1-2 tablets of codeine/acetaminophen 30/300 mg) rather than the full calculated 67 mg equivalent 1
• The CDC recommends starting opioid-naïve patients at approximately 20-30 MME/day 1
• Codeine has a higher incidence of CNS side effects (sedation, lightheadedness) compared to hydrocodone 6
• Monitor closely for inadequate analgesia or adverse effects and adjust accordingly 1

Acetaminophen dosing limits:

• Maximum daily acetaminophen should not exceed 3000-4000 mg/day to avoid hepatotoxicity 2
• With 2 tablets every 4-6 hours, patients would receive 2400-3600 mg/day of acetaminophen, which is within safe limits 2