Oxycodone 2.5 mg is Stronger Than Tramadol 12.5 mg
Oxycodone 2.5 mg is approximately 3.75 MME (morphine milligram equivalents), while tramadol 12.5 mg is approximately 2.5 MME, making oxycodone 2.5 mg the stronger option by about 1.5-fold.
Morphine Equivalence Calculations
Oxycodone Conversion
- Oxycodone has a conversion factor of 1.5 to morphine, meaning each mg of oxycodone equals 1.5 mg of morphine 1
- Therefore, 2.5 mg oxycodone = 3.75 MME (2.5 × 1.5)
- Multiple guidelines consistently report oxycodone as 1.5-2 times more potent than oral morphine 1
Tramadol Conversion
- Tramadol has a conversion factor of 0.2 to morphine, meaning each mg of tramadol equals 0.2 mg of morphine 1
- Therefore, 12.5 mg tramadol = 2.5 MME (12.5 × 0.2)
- Guidelines consistently describe tramadol as having 0.1-0.2 relative effectiveness compared to oral morphine, making it approximately one-tenth as potent as morphine 1
Direct Potency Comparison
The oxycodone dose provides 50% more morphine equivalents than the tramadol dose (3.75 MME vs 2.5 MME), making it the stronger analgesic option.
Clinical Context
- Tramadol is classified as a weak opioid (WHO Step II) with significant limitations due to its prodrug nature and requirement for CYP2D6 metabolism 1
- Oxycodone is classified as a strong opioid (WHO Step III) with more predictable and reliable analgesic effects 1
- The NCCN notes that tramadol is "less potent than other opioids and is considered to be approximately one tenth as potent as morphine" 1
Important Clinical Caveats
Tramadol's Variable Potency
- Tramadol's conversion factor ranges from 0.1-0.2, creating uncertainty in exact equivalence calculations 1
- This variability stems from tramadol's dual mechanism (weak mu-opioid agonist plus norepinephrine/serotonin reuptake inhibition) 1
- In neuropathic pain specifically, tramadol may demonstrate relatively better potency ratios compared to nociceptive pain, though this doesn't change the fundamental MME calculations 2
Safety Profile Differences
- Low-dose oxycodone carries higher risk of opioid-related adverse outcomes including overdose and opioid use disorder compared to tramadol 3
- Tramadol has a maximum daily dose of 400 mg (80 MME) due to seizure risk, particularly in elderly patients and those with hepatic/renal dysfunction 1
- Tramadol must be used cautiously with serotonergic medications due to serotonin syndrome risk 1