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Oxycodone (Roxicodone®, OxyContin®)
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| Oxycodone | |
|---|---|
| Brand Names | Roxicodone®, OxyContin®, Percocet®, Endocet® |
| Drug Class | Opioid (Full μ-agonist) |
| Primary Indication | Moderate–Severe Pain |
| Relative Potency | ~1.5× Morphine (oral) |
| Hypoglycemia Risk | N/A |
| Respiratory Depression | Yes (dose-dependent) |
| Weight Effect | Neutral |
| Elimination | Hepatic metabolism |
| Controlled Substance | Schedule II |
| FDA Approval | 1950 |
Overview
Oxycodone is a full μ-opioid receptor agonist used for the management of moderate to severe pain.
It has good oral bioavailability compared to morphine and is available in both immediate-release (IR) and extended-release (ER) formulations.
As a full agonist, oxycodone produces dose-dependent analgesia with no ceiling effect, but also carries dose-dependent risk of respiratory depression.
Mechanism of Action
Receptor Activity
- Full μ-opioid receptor agonist
- Gi-protein coupled receptor activation
Cellular Effects
- ↓ cAMP production
- ↑ Potassium efflux → neuronal hyperpolarization
- ↓ Calcium influx → ↓ substance P & glutamate release
Net Effect
- Decreased nociceptive transmission
- Altered perception of pain
Indications
- Acute moderate to severe pain
- Chronic pain requiring opioid therapy
- Cancer-related pain
- Postoperative pain
Extended-release formulations:
- Reserved for chronic pain requiring around-the-clock therapy
Contraindications
Absolute:
- Significant respiratory depression
- Acute severe bronchial asthma
- Paralytic ileus
Relative / Caution:
- Hepatic impairment
- Renal impairment
- Elderly patients
- Obstructive sleep apnea
- Concurrent benzodiazepine use
Dosing
Immediate-Release:
- 5–15 mg every 4–6 hours as needed
Extended-Release:
- Dosed every 12 hours
Dose adjustments required:
- Hepatic impairment
- Renal impairment
See:
Pharmacokinetics
Absorption:
- Oral; high bioavailability (~60–87%)
Metabolism:
- CYP3A4 → noroxycodone (inactive)
- CYP2D6 → oxymorphone (active metabolite)
Half-life:
- IR: ~3–4 hours
- ER: ~12 hours
Elimination:
- Primarily hepatic metabolism with renal excretion of metabolites
Adverse Effects
Common:
- Sedation
- Constipation
- Nausea / vomiting
- Pruritus
- Dizziness
Serious:
- Respiratory depression
- Hypotension
- Physical dependence
- Opioid use disorder
Constipation persists despite tolerance.
Drug Interactions
CYP3A4 inhibitors (↑ levels):
- Azoles
- Macrolides
- Protease inhibitors
CYP3A4 inducers (↓ levels):
- Rifampin
- Carbamazepine
CNS depressants:
- Benzodiazepines
- Alcohol
- Other opioids
Risk: additive respiratory depression
Monitoring
Clinical:
- Pain control
- Sedation level
- Respiratory rate
Risk monitoring:
- Signs of misuse or dependence
- PDMP checks when appropriate
Clinical Pearls
- Full μ agonist → no ceiling effect.
- Higher oral bioavailability than morphine.
- CYP3A4 interactions significantly affect serum levels.
- Often combined with acetaminophen — monitor total daily APAP dose.
- Schedule II controlled substance.
Toxicity
Classic opioid toxidrome:
- CNS depression
- Respiratory depression
- Miosis
- Decreased bowel sounds
Treatment:
Comparison Within Class
Compared to Morphine:
- Better oral bioavailability
- Less histamine release
Compared to Hydromorphone:
- Less potent
Compared to Hydrocodone:
- Slightly more potent