Onset of Action for Endone (Oxycodone)
Endone (oxycodone) begins working within 15-30 minutes of oral administration, with peak effects occurring at approximately 1 hour after ingestion.
Pharmacokinetic Profile of Oxycodone
Oxycodone is a semi-synthetic opioid with agonist activity at mu-, delta-, and kappa-opioid receptors. When administered orally as an immediate-release formulation (such as Endone), it has the following characteristics:
- Onset of action: 15-30 minutes 1
- Peak effect: 1 hour after administration 2
- Duration of effect: 4-6 hours for immediate-release formulations 1
- Oral bioavailability: 60-87% 2
- Plasma half-life: 3-5 hours 2
Comparison with Other Opioids
When comparing the onset of action of oxycodone to other commonly used opioids:
- Morphine: Takes approximately 15-30 minutes to begin working when given orally 3
- Hydromorphone: Has a quicker onset of action compared to morphine 3
- Codeine: Similar onset time (15-30 minutes) but less effective overall 3
Clinical Implications
The relatively rapid onset of action makes immediate-release oxycodone (Endone) appropriate for:
- Management of acute pain episodes 1
- Breakthrough pain in patients already on long-acting opioids 1
- Initial dose titration before considering extended-release formulations 1
It's important to note that while the onset begins at 15-30 minutes, the full analgesic effect may not be appreciated until closer to the 1-hour mark when peak plasma concentrations are reached 2.
Dosing Considerations
- Starting dose: Typically 5-15 mg every 4-6 hours as needed for opioid-naïve patients 1
- Elderly patients: May require lower initial doses due to altered pharmacokinetics 4
- Renal/hepatic impairment: Dose adjustments may be necessary as metabolites can accumulate 3
Important Precautions
- Do not crush, break, or chew Endone tablets as this can lead to rapid release and absorption of a potentially fatal dose 1
- The combination of oxycodone with other central nervous system depressants (especially benzodiazepines) should be avoided due to increased risk of respiratory depression 1
- Monitor for signs of sedation, particularly in the first hour after administration when drug levels are peaking 3
Clinical Pearls
- The onset of action for immediate-release oxycodone is faster than extended-release formulations (OxyContin), which are not appropriate for acute pain management 1
- When switching between opioids, use established equianalgesic dosing guidelines to maintain appropriate pain control 1
- Oxycodone is approximately 1.5-2 times more potent than oral morphine on a milligram-per-milligram basis 1
Understanding the rapid onset of action of Endone (15-30 minutes) is crucial for appropriate timing of administration and patient expectations regarding pain relief.