Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
OXYCODONE AND ACETAMINOPHEN vs ACETAMINOPHEN, ASPIRIN, AND CODEINE PHOSPHATE
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 mu-opioid receptor agonist, producing analgesia via activation of descending inhibitory pathways, while acetaminophen is a centrally acting analgesic and antipyretic, likely through inhibition of cyclooxygenase (COX) in the CNS and modulation of serotonergic pathways.
Acetaminophen: cyclooxygenase (COX) inhibitor, primarily central, analgesic and antipyretic. Aspirin: irreversible COX-1 and COX-2 inhibitor, analgesic, anti-inflammatory, antipyretic, antiplatelet. Codeine: prodrug converted to morphine; mu-opioid receptor agonist.
Management of moderate to moderately severe pain (FDA approved),Off-label: acute pain, postoperative pain
Mild to moderate pain,Fever (acetaminophen and aspirin),Inflammatory conditions (aspirin)
Oral: 5-10 mg oxycodone (with 325-650 mg acetaminophen) every 4-6 hours as needed; maximum oxycodone 60 mg/day (for immediate-release) or acetaminophen 4000 mg/day. Titrate to pain control.
1-2 tablets (each containing acetaminophen 300 mg, aspirin 300 mg, codeine phosphate 30 mg) orally every 4-6 hours as needed for pain; maximum 8 tablets/day.
Oxycodone: 3-5 hours (immediate-release), 4.5-8 hours (extended-release). Acetaminophen: 1.5-3 hours. Clinical context: Half-life may be prolonged in hepatic impairment, elderly, and renal failure.
Acetaminophen: 2-3 hours (terminal). Aspirin: 15-30 minutes (parent drug); salicylate: 2-3 hours at low doses, 15-30 hours at high doses due to saturable metabolism. Codeine: 2.5-4 hours. Clinical context: Prolonged half-life of salicylate at high doses increases risk of toxicity; hepatic impairment prolongs acetaminophen and codeine half-lives.
Oxycodone is extensively metabolized in the liver via CYP3A4 (primarily) and CYP2D6 (minor) to noroxycodone, oxymorphone, and other metabolites. Acetaminophen is metabolized in the liver mainly via glucuronidation and sulfation with a minor CYP2E1 pathway producing toxic NAPQI.
Acetaminophen: hepatic via CYP2E1, CYP1A2, CYP3A4; glucuronidation and sulfation; NAPQI formation. Aspirin: hepatic hydrolysis to salicylate; conjugation with glycine and glucuronic acid. Codeine: hepatic via CYP2D6 to morphine (active); also via CYP3A4 to norcodeine.
Oxycodone: renal (primarily as noroxycodone, oxymorphone, and conjugated metabolites; <10% unchanged). Acetaminophen: renal (85-90% as sulfate and glucuronide conjugates; 2-4% unchanged; 8-10% as cysteine and mercapturate conjugates). Biliary/fecal excretion: minor (<5% for both).
Acetaminophen: renal excretion of metabolites (glucuronide and sulfate conjugates, ~85-90%), minor parent drug (<5%). Aspirin: renal excretion of salicylate and its metabolites (salicyluric acid, glucuronides, gentisic acid), dose-dependent; at therapeutic doses, ~50-80% as free salicylate and conjugates. Codeine: renal excretion of free and conjugated codeine (about 90%) and metabolites (morphine, norcodeine).
Oxycodone: 38-45% (primarily to albumin). Acetaminophen: 10-25% (minimal binding).
Acetaminophen: 10-25% (albumin). Aspirin: 50-80% (albumin), dose-dependent; salicylate: 75-90% (albumin). Codeine: ~7% (albumin).
Oxycodone: 2.6-3.0 L/kg (wide distribution into tissues). Acetaminophen: 0.9-1.0 L/kg (uniformly distributed in body fluids).
Acetaminophen: 0.9-1.0 L/kg (large distribution including liver). Aspirin: 0.15-0.2 L/kg (low Vd, confined to plasma and extracellular fluid); salicylate: 0.2-0.3 L/kg. Codeine: 3-6 L/kg (extensive tissue distribution). Clinical meaning: Large Vd for codeine suggests extensive tissue binding; aspirin Vd is small, consistent with limited extravascular distribution.
Oral immediate-release: oxycodone 60-87%, acetaminophen 68-88%. Oral extended-release: oxycodone 60-87% (less variable). Rectal: variable (unspecified for this combination).
Oral: Acetaminophen: 85-95%. Aspirin: 40-60% (due to first-pass hydrolysis to salicylate). Codeine: ~50% due to first-pass metabolism.
Cr Cl ≥60 m L/min: no adjustment; Cr Cl 30-59 m L/min: acetaminophen no change, oxycodone consider 75% of usual dose; Cr Cl 10-29 m L/min: acetaminophen extend interval to q6h, oxycodone consider 50% of usual dose; Cr Cl <10 m L/min: acetaminophen avoid or 650 mg q8h, oxycodone 50% of usual dose; hemodialysis: acetaminophen 650 mg q8h, oxycodone 25-50% of usual dose.
GFR 30-59 m L/min: Administer every 6 hours; maximum 6 tablets/day. GFR 15-29 m L/min: Administer every 12 hours; maximum 4 tablets/day. GFR <15 m L/min: Not recommended due to accumulation of codeine metabolites.
Child-Pugh A: no adjustment; Child-Pugh B: oxycodone reduce dose by 50%, acetaminophen maximum 2000 mg/day; Child-Pugh C: oxycodone reduce dose by 75%, acetaminophen maximum 2000 mg/day; severe hepatic impairment: avoid acetaminophen component.
Child-Pugh Class A: No adjustment. Child-Pugh Class B: Reduce dose by 50% and extend interval to every 6 hours; maximum 4 tablets/day. Child-Pugh Class C: Contraindicated.
Children ≥6 months: 0.05-0.15 mg/kg oxycodone (based on oxycodone component) every 4-6 hours, maximum single dose 5 mg; acetaminophen 10-15 mg/kg/dose, maximum 75 mg/kg/day (up to 4000 mg/day). Weight-based oxycodone not to exceed adult dose.
Not recommended for children <12 years due to aspirin risk of Reye syndrome. For children ≥12 years: Dose based on codeine component (0.5-1 mg/kg/dose) with maximum acetaminophen 75 mg/kg/day and aspirin 100 mg/kg/day. Typical: 1 tablet (acetaminophen 300 mg/aspirin 300 mg/codeine 30 mg) every 4-6 hours as needed; max 4 tablets/day.
Start at 50% of adult dose (oxycodone 2.5-5 mg every 6 hours), titrate cautiously; maximum acetaminophen 3000 mg/day due to decreased hepatic reserves; monitor for renal impairment and avoid if Cr Cl <30 m L/min.
Start with lowest effective dose (e.g., 1 tablet every 6 hours); monitor renal and hepatic function; maximum 6 tablets/day due to increased sensitivity and risk of adverse effects.
Risk of addiction, abuse, and misuse; life-threatening respiratory depression; neonatal opioid withdrawal syndrome; accidental ingestion may be fatal; risk of hepatotoxicity with acetaminophen overdose.
Risk of medication errors: confusion between different strengths and concentrations of acetaminophen can result in accidental overdose and fatal hepatotoxicity. Aspirin use in children and teenagers with viral infections is associated with Reye's syndrome.
Addiction, abuse, and misuse; respiratory depression; neonatal opioid withdrawal syndrome; interactions with CNS depressants; hepatotoxicity (acetaminophen); severe hypotension; adrenal insufficiency; seizures; increased risk of overdose in patients with head injury or COPD.
Hepatotoxicity (acetaminophen dose >4 g/day), Reye's syndrome (aspirin in children), respiratory depression (codeine), tolerance/dependence, bleeding risk (aspirin), GI toxicity, renal impairment, hypersensitivity reactions.
Hypersensitivity to oxycodone, acetaminophen, or any component; significant respiratory depression; acute or severe bronchial asthma; paralytic ileus; known or suspected gastrointestinal obstruction; severe hepatic impairment (acetaminophen).
Hypersensitivity to any component, active peptic ulcer disease, bleeding disorders, severe hepatic impairment, severe respiratory depression, children with viral illness (aspirin), pregnancy (third trimester for aspirin, codeine cautious).
Avoid alcohol consumption; increases risk of hepatotoxicity from acetaminophen and potentiates CNS depression. Grapefruit juice may increase oxycodone absorption; avoid concurrent use. High-fat meals can delay oxycodone peak concentration, potentially reducing rapid pain relief. No specific restrictions with other foods.
Avoid alcohol due to increased risk of acetaminophen hepatotoxicity and aspirin-induced GI bleeding. Avoid large amounts of caffeine or high-tyramine foods (e.g., aged cheeses, cured meats) as they may affect CYP2D6 metabolism of codeine.
First trimester: Risk of neural tube defects not significantly increased with therapeutic use; opioid dependence may increase risk of congenital malformations (e.g., gastroschisis). Second/third trimester: Chronic use may cause fetal opioid dependence, leading to neonatal abstinence syndrome (NAS). Late third trimester: Risk of respiratory depression in neonate if used near delivery.
Acetaminophen: Generally considered low risk; association with ASD and ADHD with prolonged use not fully established. Aspirin: First trimester: possible increased risk of gastroschisis; second trimester: relatively safe; third trimester: risk of premature closure of ductus arteriosus, oligohydramnios, and increased peripartum hemorrhage. Codeine: First trimester: possible neural tube defects; second and third trimesters: risk of respiratory depression, withdrawal in neonate with chronic use; neonatal opioid withdrawal syndrome (NOWS) possible.
Excreted into breast milk in low concentrations. M/P ratio for oxycodone: 3.2:1; acetaminophen: approximately 1.0. Considered compatible with breastfeeding with caution; monitor infant for sedation and feeding difficulties. Avoid if maternal codeine use due to CYP2D6 ultrarapid metabolism concerns (though oxycodone less affected).
Acetaminophen: M/P ratio approximately 0.91-1.42; considered safe. Aspirin: M/P ratio 0.08-0.15; high doses may cause Reye's syndrome; avoid or use low doses. Codeine: M/P ratio about 2.5; variable metabolism; risk of CNS depression in infant; avoid due to potential for toxicity in CYP2D6 ultrarapid metabolizers.
No standard dose adjustment required for maternal pharmacokinetic changes. Increased renal clearance in pregnancy may slightly reduce acetaminophen levels, but therapeutic effect maintained. Oxycodone metabolism via CYP3A4 and 2D6; pregnancy-induced enzyme changes may alter clearance, but clinical significance unclear. Use lowest effective dose, avoid NSAIDs if co-prescribed.
Acetaminophen: No dose adjustment needed. Aspirin: Avoid in third trimester; use lowest effective dose if necessary. Codeine: Avoid in pregnancy; if used, lowest effective dose for shortest duration; caution for CYP2D6 polymorphism. Pharmacokinetic changes: Increased clearance of codeine during pregnancy may require higher doses but risk outweighs benefit.
Maximum daily acetaminophen dose is 4000 mg from all sources; prescribed combination tablets contribute to this limit. Oxycodone immediate-release duration is 3-6 hours; avoid crushing extended-release formulations. Both components have abuse potential; screen for opioid use disorder. In renal impairment, adjust dosing interval for oxycodone; avoid in Cr Cl <30 m L/min. In hepatic impairment, the acetaminophen component may be hepatotoxic; avoid in severe disease. Coadministration with serotonergic agents may precipitate serotonin syndrome. Naloxone is the reversal agent for oxycodone; acetylcysteine for acetaminophen overdose.
Combination analgesic with acetaminophen (hepatotoxic at high doses), aspirin (antiplatelet, GI irritant, contraindicated in children <12 due to Reye's syndrome), and codeine (prodrug to morphine via CYP2D6; efficacy depends on CYP2D6 phenotype; risk of CNS/respiratory depression). Avoid in severe hepatic/renal impairment, active peptic ulcer, bleeding disorders, or concomitant use of other CNS depressants. Maximum acetaminophen dose from all sources: 4 g/day.
Take exactly as prescribed; do not increase dose or frequency without consulting your doctor.,Do not take other products containing acetaminophen (e.g., Tylenol, cold medications) to avoid exceeding the maximum daily dose of 4000 mg.,Avoid alcohol while taking this medication; liver damage risk increases with alcohol use.,Do not crush, break, or chew tablets; swallow whole to avoid rapid release of oxycodone.,This medication can cause drowsiness or dizziness; avoid driving or operating machinery until you know how it affects you.,Store securely out of sight and reach of children; dispose of unused medication via a drug take-back program.,Take with food if nausea occurs; avoid high-fat meals as they may delay absorption.,Do not stop abruptly; withdrawal symptoms may occur. Consult your doctor for a tapering schedule.
Do not exceed recommended dose; acetaminophen overdosage can cause serious liver damage.,Do not take with other products containing acetaminophen or aspirin.,Avoid alcohol while taking this medication to reduce risk of liver toxicity and GI bleeding.,This product contains aspirin; do not give to children/teenagers with chickenpox or flu-like symptoms to avoid Reye's syndrome.,May cause drowsiness; do not drive or operate machinery until you know how you react.,Codeine is a narcotic pain reliever with abuse potential; use exactly as prescribed.,Seek medical attention if you experience signs of allergic reaction (rash, difficulty breathing) or bleeding (black/tarry stools, unusual bruising).
"Phenobarbital, a potent inducer of cytochrome P450 (CYP) enzymes, particularly CYP3A4 and CYP2D6, significantly increases the hepatic metabolism of oxycodone, a prodrug that requires CYP3A4-mediated N-demethylation to noroxycodone and CYP2D6-mediated O-demethylation to oxymorphone for its analgesic effects. This induction reduces the systemic exposure and peak plasma concentration of active oxycodone and its active metabolite oxymorphone, leading to diminished analgesic efficacy and potential opioid withdrawal symptoms in patients on chronic opioid therapy. Clinically, patients may require substantially higher doses of oxycodone to achieve pain relief, increasing the risk of dose-related adverse effects if the interaction is not recognized."
"The co-administration of oxycodone, a mu-opioid receptor agonist, and gamma-hydroxybutyric acid (GHB), a central nervous system depressant with activity at GABA-B and GHB receptors, results in additive or synergistic respiratory depression and CNS depression. This interaction potentiates the risk of severe hypoventilation, coma, and fatal overdose, especially in non-tolerant users or at therapeutic doses. The combined sedation also increases the likelihood of hypotension, bradycardia, and impaired psychomotor function, necessitating extreme caution."
"The coadministration of oxycodone, a mu-opioid receptor agonist with central nervous system (CNS) depressant effects, and perampanel, a noncompetitive AMPA receptor antagonist that also causes CNS depression, produces additive sedative and respiratory depressant effects. This synergy increases the risk of excessive sedation, impaired cognitive function, and potentially life-threatening respiratory depression. Patients may experience profound somnolence, confusion, and an increased fall risk, necessitating dose adjustments or avoidance."
"Pirenzepine, a selective M1 muscarinic antagonist, reduces gastrointestinal motility and secretions, while codeine, an opioid agonist, also decreases gastrointestinal motility via mu-opioid receptors. Concurrent use leads to additive anticholinergic and opioid effects, resulting in enhanced risk of severe constipation, paralytic ileus, and central nervous system depression. Clinically, patients may experience exacerbated sedation, respiratory depression, and urinary retention."
"Ropinirole, a non-ergoline dopamine agonist used in Parkinson's disease and restless legs syndrome, may reduce the analgesic efficacy of codeine. This is likely due to pharmacodynamic antagonism at central dopamine and opioid receptors, as well as potential pharmacokinetic interactions that decrease the conversion of codeine to its active metabolite morphine via CYP2D6 inhibition by ropinirole. The resultant blunted opioid response can lead to inadequate pain control, necessitating dose adjustment or alternative therapy."
"Vemurafenib induces CYP3A4, significantly reducing the plasma concentrations of codeine, which is metabolized via CYP3A4 to its active metabolite morphine. This may diminish codeine's analgesic efficacy, potentially leading to inadequate pain control. Additionally, reduced formation of morphine may lower the risk of opioid-related adverse effects."
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about OXYCODONE AND ACETAMINOPHEN vs ACETAMINOPHEN, ASPIRIN, AND CODEINE PHOSPHATE, answered by our medical review team.
OXYCODONE AND ACETAMINOPHEN is a Opioid Agonist that works by Oxycodone is a full mu-opioid receptor agonist, producing analgesia via activation of descending inhibitory pathways, while acetaminophen is a centrally acting analgesic and antipyretic, likely through inhibition of cyclooxygenase (COX) in the CNS and modulation of serotonergic pathways.. ACETAMINOPHEN, ASPIRIN, AND CODEINE PHOSPHATE is a Opioid Agonist that works by Acetaminophen: cyclooxygenase (COX) inhibitor, primarily central, analgesic and antipyretic. Aspirin: irreversible COX-1 and COX-2 inhibitor, analgesic, anti-inflammatory, antipyretic, antiplatelet. Codeine: prodrug converted to morphine; mu-opioid receptor agonist.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between OXYCODONE AND ACETAMINOPHEN and ACETAMINOPHEN, ASPIRIN, AND CODEINE PHOSPHATE depend on the specific clinical indication. These are both Opioid Agonist agents and are not directly interchangeable by dose. A physician or clinical pharmacist should guide any therapeutic switching decisions.
The standard adult dose of OXYCODONE AND ACETAMINOPHEN is: Oral: 5-10 mg oxycodone (with 325-650 mg acetaminophen) every 4-6 hours as needed; maximum oxycodone 60 mg/day (for immediate-release) or acetaminophen 4000 mg/day. Titrate to pain control.. The standard adult dose of ACETAMINOPHEN, ASPIRIN, AND CODEINE PHOSPHATE is: 1-2 tablets (each containing acetaminophen 300 mg, aspirin 300 mg, codeine phosphate 30 mg) orally every 4-6 hours as needed for pain; maximum 8 tablets/day.. Dosing should always be individualized based on indication, renal and hepatic function, age, and other patient factors.
A moderate-severity drug interaction has been identified when combining OXYCODONE AND ACETAMINOPHEN and ACETAMINOPHEN, ASPIRIN, AND CODEINE PHOSPHATE. The risk or severity of adverse effects can be increased when Codeine is combined with Oxycodone. Consult your prescriber before combining these medications.
The maternal-fetal safety profiles differ. OXYCODONE AND ACETAMINOPHEN is classified as Category D/X. First trimester: Risk of neural tube defects not significantly increased with therapeutic use; opioid dependence may increase risk of congenital malformations (e.g., gastroschisis). ACETAMINOPHEN, ASPIRIN, AND CODEINE PHOSPHATE is classified as Category D/X. Acetaminophen: Generally considered low risk; association with ASD and ADHD with prolonged use not fully established. Aspirin: First trimester: possible increased risk of gastrosch. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.