What is the highest bioavailability route for oxycodone?

Highest Bioavailability Route for Oxycodone

Intravenous administration provides the highest bioavailability route for oxycodone at 100%, compared to oral bioavailability of 60-87%. 1

Bioavailability Comparison by Route

1. Intravenous (IV): 100% bioavailability (reference standard)

   • Provides immediate and complete drug delivery to systemic circulation
   • Bypasses first-pass metabolism in the liver

2. Oral: 60-87% bioavailability 1, 2

   • Higher than many other oral opioids (such as morphine)
   • This relatively high oral bioavailability is due to lower presystemic and first-pass metabolism 1
   • Makes oxycodone particularly effective for oral administration

3. Intranasal: 46% bioavailability (with high variability) 3

   • Peak plasma concentration reached in median time of 25 minutes
   • Shows large interindividual differences

4. Subcutaneous: Similar to IV (near 100%)

   • Though not specifically quantified for oxycodone in the evidence, subcutaneous administration generally provides high bioavailability similar to IV for most opioids

Clinical Implications

• The high oral bioavailability of oxycodone (60-87%) makes it particularly suitable for oral administration compared to other opioids like morphine 2, 4
• When rapid onset is needed, IV administration provides the fastest and most complete absorption 2
• For patients unable to take oral medications, parenteral routes (IV, subcutaneous) provide the highest bioavailability 2
• Transdermal formulations are not available for oxycodone (unlike fentanyl or buprenorphine) 2

Practical Considerations

• Despite IV having the highest bioavailability, oral administration is generally preferred for chronic pain management due to convenience and cost 2
• IV administration should be reserved for patients requiring urgent pain relief or those unable to take oral medications 2
• The relatively high and consistent oral bioavailability of oxycodone makes it advantageous in patients with unpredictable absorption, such as those with severe hepatic cirrhosis 5

Relative Potency

• When converting from oral to parenteral (IV or subcutaneous) opioid administration, a dose reduction is typically needed due to the higher bioavailability
• The oral-to-parenteral potency ratio for oxycodone is not specifically stated in the evidence, but would likely follow similar patterns to morphine (approximately 1:3) 2, 6

For most clinical situations requiring oxycodone, the oral route provides good bioavailability with convenient administration, but when maximum bioavailability is needed, the intravenous route is superior.