Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
OXYCONTIN vs ETHRIL 500
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Oxycodone is a full opioid agonist with relative selectivity for the mu-opioid receptor, although it can bind to other opioid receptors at higher doses. The principal therapeutic action of oxycodone is analgesia. Like all full opioid agonists, there is no ceiling effect for analgesia with oxycodone. Clinically, dosage is titrated to provide adequate analgesia and may be limited by adverse reactions, including respiratory and CNS depression.
Acetaminophen (paracetamol) is a central analgesic and antipyretic agent whose exact mechanism is not fully understood but is thought to involve inhibition of cyclooxygenase (COX) enzymes in the brain, primarily COX-2, and activation of descending serotonergic pathways. It has weak peripheral anti-inflammatory activity.
Management of pain severe enough to require daily, around-the-clock, long-term opioid treatment and for which alternative treatment options are inadequate,Off-label: Treatment of opioid dependence (as part of substitution therapy)
Mild to moderate pain,Fever
10 mg orally every 12 hours; titrate based on pain severity and prior opioid exposure.
500 mg orally every 6 hours as needed for pain. Maximum daily dose: 2000 mg.
4.5-5.0 hours (immediate-release); controlled-release OXYCONTIN has an apparent half-life of 4.5-8.7 hours. Terminal half-life is ~3.5-4 hours for immediate-release, reflecting context-sensitive elimination.
Terminal elimination half-life is 2-4 hours in adults with normal renal function; prolonged to 6-12 hours in hepatic impairment or overdose.
Oxycodone is metabolized primarily via CYP3A4 to noroxycodone (major metabolite) and via CYP2D6 to oxymorphone (minor metabolite). Both metabolites are active, with oxymorphone having higher potency. Oxycodone and its metabolites are conjugated and excreted in urine.
Primarily metabolized in the liver via glucuronidation and sulfation; a minor pathway via CYP2E1 (and CYP1A2, CYP3A4) produces the toxic metabolite N-acetyl-p-benzoquinone imine (NAPQI), which is normally detoxified by glutathione.
Primarily renal (90% as metabolites, 10% unchanged). Also biliary/fecal (10%).
Renal excretion of unchanged drug and glucuronide conjugate accounts for 90-95% of elimination; biliary/fecal elimination accounts for 5-10%.
38-45%, primarily bound to albumin.
10-25% bound to plasma proteins (albumin).
2.6-3.0 L/kg. Extensive tissue distribution, high Vd indicates penetration into peripheral tissues.
0.9-1.1 L/kg; indicates extensive distribution into body fluids including CSF.
Oral immediate-release: 60-87% (first-pass metabolism). Oral extended-release (Oxy Contin): 60-87% (similar). Intravenous: 100%.
Oral: 75-90% (first-pass metabolism reduces from near 100% absorption); IV: 100%; Rectal: 70-85%.
Cr Cl 30-60 m L/min: reduce dose by 25%; Cr Cl <30 m L/min: reduce dose by 50% and administer every 12 hours; hemodialysis: avoid use.
GFR 30-50 m L/min: 500 mg every 8 hours. GFR 10-29 m L/min: 500 mg every 12 hours. GFR <10 m L/min: 500 mg every 24 hours.
Child-Pugh Class A: no adjustment; Child-Pugh Class B: reduce dose by 50%; Child-Pugh Class C: avoid use.
Child-Pugh Class A: no adjustment. Child-Pugh Class B: 500 mg every 8 hours. Child-Pugh Class C: 500 mg every 12 hours.
Not approved for pediatric patients <18 years; for children ≥11 years (opioid-tolerant): 0.2 mg/kg orally every 12 hours, titrate; maximum single dose 10 mg.
Children <2 years: not recommended. Children 2-12 years: 10-15 mg/kg/dose every 6 hours, maximum 60 mg/kg/day. Adolescents >12 years: same as adult.
Initiate at 5 mg orally every 12 hours; titrate cautiously; monitor for respiratory depression and constipation.
Initiate at 500 mg every 8 hours; increase interval if needed due to reduced renal function; consider maximum daily dose of 1500 mg.
WARNING: ADDICTION, ABUSE, AND MISUSE; LIFE-THREATENING RESPIRATORY DEPRESSION; ACCIDENTAL INGESTION; NEONATAL OPIOID WITHDRAWAL SYNDROME; and RISKS FROM CONCOMITANT USE WITH BENZODIAZEPINES OR OTHER CNS DEPRESSANTS
Risk of severe liver injury; do not exceed 4,000 mg per day in adults or 2,000 mg per day in patients with liver disease. Concomitant use with other acetaminophen-containing products may lead to overdose.
Addiction, abuse, and misuse: Oxy Contin exposes patients and other users to the risks of opioid addiction, abuse, and misuse, which can lead to overdose and death. Assess each patient's risk prior to prescribing, and monitor all patients regularly for the development of these behaviors or conditions.,Life-threatening respiratory depression: Serious, life-threatening, or fatal respiratory depression may occur. Monitor for respiratory depression, especially during initiation of therapy or following a dose increase. Instruct patients to swallow tablets whole; crushing, chewing, or dissolving can cause rapid release and absorption of a potentially fatal dose.,Accidental ingestion: Accidental ingestion of even one dose of Oxy Contin, especially by children, can result in a fatal overdose of oxycodone.,Neonatal opioid withdrawal syndrome: Prolonged use of Oxy Contin during pregnancy can result in withdrawal in the neonate. Neonatal opioid withdrawal syndrome, unlike opioid withdrawal in adults, may be life-threatening if not recognized and treated.,Risks from concomitant use with benzodiazepines or other CNS depressants: Concomitant use of opioids with benzodiazepines or other CNS depressants, including alcohol, may result in profound sedation, respiratory depression, coma, and death. Reserve concomitant prescribing for use in patients for whom alternative treatment options are inadequate.
Hepatotoxicity, especially with doses >4 g/day or in patients with hepatic impairment; risk of acute generalized exanthematous pustulosis (AGEP); serious skin reactions (Stevens-Johnson syndrome, toxic epidermal necrolysis); avoid use with alcohol or other hepatotoxic drugs.
Significant respiratory depression,Acute or severe bronchial asthma in an unmonitored setting or in the absence of resuscitative equipment,Known or suspected gastrointestinal obstruction, including paralytic ileus,Hypersensitivity (e.g., anaphylaxis) to oxycodone or any other components of the product
Hypersensitivity to acetaminophen or any component; severe hepatic impairment; use of other acetaminophen-containing products concurrently.
Avoid alcohol, which can increase oxycodone absorption and central nervous system depression. Grapefruit juice may alter oxycodone metabolism; limit or avoid consumption. No specific food restrictions, but high-fat meals may slow absorption slightly; take with or without food consistently.
No significant food interactions. Alcohol increases risk of hepatotoxicity and should be avoided.
FDA Pregnancy Category C prior to 2020; no adequate studies in pregnant women. First trimester: Limited data suggest possible increased risk of neural tube defects (1.8-fold) and oral clefts (1.5-fold) with opioid use, but confounded by underlying conditions. Second and third trimesters: Chronic use may cause fetal opioid dependence and neonatal abstinence syndrome (NAS); maternal withdrawal may precipitate preterm labor. Avoid prolonged use near term due to risk of neonatal respiratory depression.
ETHIRIL 500 (ethyl alcohol 500 mg) is not a standard drug; assuming it refers to ethanol. Teratogenic: First trimester: Increased risk of fetal alcohol spectrum disorders (FASD) including craniofacial abnormalities, growth deficiency, and neurodevelopmental deficits with chronic heavy use. Second trimester: Risk of spontaneous abortion and intrauterine growth restriction (IUGR). Third trimester: Risk of preterm birth, low birth weight, and neonatal withdrawal syndrome. No safe threshold established.
Oxycodone is excreted into breast milk; relative infant dose is approximately 2.7–8.8% of maternal weight-adjusted dose. M/P ratio unknown. Monitor infant for sedation, respiratory depression, and poor feeding. American Academy of Pediatrics considers oxycodone compatible with breastfeeding with caution; avoid rapid accumulation in mothers with impaired metabolism (CYP2D6 poor metabolizers).
Ethanol is excreted into breast milk. Milk-to-plasma ratio approximately 1.0. Peak milk levels occur 30-60 minutes after ingestion. Chronic heavy use may impair infant motor development and cause sedation. Avoid breastfeeding within 2 hours of alcohol consumption; excessive use contraindicated.
Pregnancy increases oxycodone clearance by 1.3- to 2.5-fold due to enhanced hepatic metabolism (CYP3A4 and CYP2D6 induction) and increased renal blood flow. Dose adjustments may be necessary to maintain analgesia; clinical monitoring for pain control and withdrawal symptoms is essential. Titrate to effect; avoid abrupt discontinuation. Postpartum clearance returns to baseline over 1-2 weeks.
No therapeutic dosing; ethanol is not indicated in pregnancy. If used inadvertently, pharmacokinetic changes: increased volume of distribution may lower peak alcohol concentration, but no dose adjustment recommendation. Avoidance is critical.
Oxy Contin is an extended-release formulation of oxycodone, indicated for around-the-clock pain management. Do not crush, chew, or break tablets, as this can lead to rapid release and fatal overdose. Use with caution in patients with respiratory compromise, head injury, or increased intracranial pressure. Monitor for signs of misuse, abuse, or addiction. Abrupt discontinuation may precipitate withdrawal; taper dose gradually. Constipation is common; consider prophylactic laxatives. Contraindicated in severe asthma, paralytic ileus, or hypersensitivity.
ETHRIL 500 (acetaminophen 500 mg) is hepatotoxic in overdose; maximum daily dose is 4 g in adults, but reduce to 2 g in patients with hepatic impairment, alcoholism, or malnutrition. Administer N-acetylcysteine for overdose within 8 hours for best efficacy.
Take Oxy Contin exactly as prescribed, usually every 12 hours. Do not take more or less than directed.,Swallow the tablet whole with water. Do not crush, chew, or break the tablet, as this can cause a dangerous overdose.,Avoid alcohol and other central nervous system depressants (e.g., benzodiazepines, sedatives) as they increase the risk of severe sedation, respiratory depression, and death.,Do not stop taking Oxy Contin suddenly; ask your doctor how to safely discontinue the medication to avoid withdrawal symptoms.,Common side effects include constipation, nausea, drowsiness, and dizziness. Contact your doctor if you experience severe constipation, difficulty breathing, or signs of allergic reaction.,Store Oxy Contin in a secure place out of sight and reach of children and pets. Dispose of unused medication via a drug take-back program.,Do not drive or operate heavy machinery until you know how Oxy Contin affects you.,Inform all healthcare providers that you are taking Oxy Contin, especially before surgery or emergency treatment.
Do not exceed 4 g (eight 500 mg tablets) per day.,Avoid alcohol while taking this medication.,Do not combine with other acetaminophen-containing products.,Seek immediate medical attention if overdose is suspected.,Take with or without food as needed.
No interactions on record
No interactions on record
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about OXYCONTIN vs ETHRIL 500, answered by our medical review team.
OXYCONTIN is a Opioid Analgesic that works by Oxycodone is a full opioid agonist with relative selectivity for the mu-opioid receptor, although it can bind to other opioid receptors at higher doses. The principal therapeutic action of oxycodone is analgesia. Like all full opioid agonists, there is no ceiling effect for analgesia with oxycodone. Clinically, dosage is titrated to provide adequate analgesia and may be limited by adverse reactions, including respiratory and CNS depression.. ETHRIL 500 is a Macrolide Antibiotic that works by Acetaminophen (paracetamol) is a central analgesic and antipyretic agent whose exact mechanism is not fully understood but is thought to involve inhibition of cyclooxygenase (COX) enzymes in the brain, primarily COX-2, and activation of descending serotonergic pathways. It has weak peripheral anti-inflammatory activity.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between OXYCONTIN and ETHRIL 500 depend on the specific clinical indication. These are agents from distinct pharmacological classes and are not directly interchangeable by dose. A physician or clinical pharmacist should guide any therapeutic switching decisions.
The standard adult dose of OXYCONTIN is: 10 mg orally every 12 hours; titrate based on pain severity and prior opioid exposure.. The standard adult dose of ETHRIL 500 is: 500 mg orally every 6 hours as needed for pain. Maximum daily dose: 2000 mg.. Dosing should always be individualized based on indication, renal and hepatic function, age, and other patient factors.
No direct drug-drug interaction has been formally documented between OXYCONTIN and ETHRIL 500 in current clinical databases. However, individual patient risk factors including other medications, organ function, and comorbidities should always be evaluated by a qualified healthcare provider.
The maternal-fetal safety profiles differ. OXYCONTIN is classified as Category C. FDA Pregnancy Category C prior to 2020; no adequate studies in pregnant women. First trimester: Limited data suggest possible increased risk of neural tube defects (1.8-fold) and o. ETHRIL 500 is classified as Category C. ETHIRIL 500 (ethyl alcohol 500 mg) is not a standard drug; assuming it refers to ethanol. Teratogenic: First trimester: Increased risk of fetal alcohol spectrum disorders (FASD) in. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.