Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
ANEXSIA 7.5/650 vs ANEXSIA 5/325
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Hydrocodone is a mu-opioid receptor agonist that inhibits ascending pain pathways and alters pain perception; acetaminophen inhibits cyclooxygenase (COX) enzymes, primarily in the CNS, reducing prostaglandin synthesis and fever.
Hydrocodone is a semi-synthetic opioid agonist that binds to mu-opioid receptors in the CNS, inhibiting ascending pain pathways and altering pain perception. Acetaminophen is a para-aminophenol derivative with analgesic and antipyretic effects, primarily through central COX-2 inhibition and activation of descending serotonergic pathways.
Management of acute pain severe enough to require an opioid analgesic and for which alternative treatments are inadequate
Management of moderate to moderately severe pain where an opioid analgesic is appropriate
1 tablet orally every 4 to 6 hours as needed; maximum 6 tablets per day.
1-2 tablets orally every 4-6 hours as needed for pain; maximum 8 tablets per day.
Hydrocodone: Terminal half-life 3.8-7.2 hours (mean 5.6 h). Acetaminophen: 1.5-2.5 hours (therapeutic) but prolonged to >4 hours in overdose with hepatotoxicity risk.
Oxycodone: terminal half-life 3.2-4.3 hours (immediate-release); prolonged in hepatic impairment. Acetaminophen: terminal half-life 2-3 hours (therapeutic doses); prolonged in hepatic impairment or overdose.
Hydrocodone: CYP3A4 and CYP2D6; acetaminophen: primarily liver glucuronidation (UGT1A1, UGT1A6, UGT1A9) and sulfation (SULT1A1, SULT1A3), with minor CYP2E1 oxidation.
Hydrocodone: primarily hepatic via CYP3A4 and CYP2D6 to active metabolites (hydromorphone). Acetaminophen: hepatic metabolism via conjugation (glucuronidation, sulfation) and CYP2E1-mediated oxidation to toxic NAPQI.
Hydrocodone: Renal elimination of metabolites (hydromorphone, norhydrocodone) and unchanged drug accounts for ~60-90% of clearance. Acetaminophen: ~85% of dose is excreted in urine as glucuronide and sulfate conjugates; 5-10% unchanged; 2-5% as mercapturate.
Oxycodone: renal excretion of metabolites (conjugated and unconjugated) and parent drug; ~10% excreted unchanged. Acetaminophen: renal excretion of metabolites (glucuronide and sulfate conjugates); ~2-4% excreted unchanged.
Hydrocodone: ~36% bound to serum proteins. Acetaminophen: 10-25% bound (minimal binding).
Oxycodone: 38-45% bound to albumin and alpha-1-acid glycoprotein. Acetaminophen: 10-25% bound to albumin at therapeutic concentrations.
Hydrocodone: Vd ~3-5 L/kg (wide distribution). Acetaminophen: Vd ~0.9-1.0 L/kg (primarily body water).
Oxycodone: Vd 2.0-3.0 L/kg; distributes extensively into tissues. Acetaminophen: Vd 0.8-1.0 L/kg; relatively uniform distribution.
Oral: Hydrocodone ~70-80% (variable first-pass). Acetaminophen ~63-89% (mean 75-80%).
Oxycodone: oral bioavailability 60-87% (immediate-release). Acetaminophen: oral bioavailability 88-98% (therapeutic doses).
Cr Cl <30 m L/min: contraindicated; Cr Cl 30-60 m L/min: maximum 3 tablets per day; given the hydrocodone component, avoid in severe renal impairment.
GFR 30-50 m L/min: use with caution, increase dosing interval to every 6 hours; GFR <30 m L/min: avoid use due to hydrocodeone accumulation.
Child-Pugh Class A: no adjustment; Child-Pugh Class B: reduce dose by 50% and monitor; Child-Pugh Class C: contraindicated due to hydrocodone.
Child-Pugh A: no adjustment; Child-Pugh B: reduce dose by 50% and monitor; Child-Pugh C: contraindicated.
Not recommended in pediatric patients due to risk of respiratory depression; for ages <18, contraindicated.
Not recommended for children under 18 years due to risk of respiratory depression.
Initiate with lowest effective dose, monitor for respiratory depression and constipation; maximum 4 tablets per day in patients >65 years.
Start with lowest dose (1 tablet every 6 hours), monitor renal and hepatic function, and avoid in frail elderly due to increased fall and cognitive impairment risk.
Risk of addiction, abuse, and misuse; life-threatening respiratory depression; accidental ingestion (especially in children) can be fatal; neonatal opioid withdrawal syndrome; cytochrome P450 3A4 interaction (concomitant use with CYP3A4 inhibitors may increase hydrocodone levels); risk of medication errors (confusion between different strengths).
Risk of addiction, abuse, and misuse; life-threatening respiratory depression; accidental ingestion; neonatal opioid withdrawal syndrome; risks from concomitant use with benzodiazepines or other CNS depressants; and hepatotoxicity from acetaminophen overdose.
Addiction, abuse, and misuse; respiratory depression; neonatal opioid withdrawal syndrome; interactions with CNS depressants; risk of serotonin syndrome with serotonergic drugs; adrenal insufficiency; hypotension; seizures; gastrointestinal obstruction; severe cutaneous reactions (acetaminophen); hepatotoxicity (acetaminophen overdose); acute abdominal conditions; impaired mental/physical abilities; elderly/debilitated patients; renal/hepatic impairment.
Risk of opioid addiction, abuse, and misuse; life-threatening respiratory depression; accidental ingestion; neonatal opioid withdrawal syndrome; risks from concomitant use with benzodiazepines or other CNS depressants; hepatotoxicity; adrenal insufficiency; severe hypotension; gastrointestinal obstruction; seizure; and serotonin syndrome.
Significant respiratory depression; acute or severe bronchial asthma (without monitoring or resuscitative equipment); known or suspected gastrointestinal obstruction (including paralytic ileus); hypersensitivity to hydrocodone or acetaminophen; use with MAOIs or within 14 days of such therapy.
Hypersensitivity to hydrocodone or acetaminophen; significant respiratory depression; acute or severe bronchial asthma; GI obstruction; known or suspected paralytic ileus; severe hepatic impairment; and concurrent use of MAOIs within 14 days.
Avoid alcohol due to increased risk of acetaminophen hepatotoxicity and additive CNS depression. Grapefruit juice may increase hydrocodone absorption; consider avoiding. No other significant food interactions.
Avoid alcohol. Grapefruit juice may enhance side effects; limit intake. Take with food to reduce gastrointestinal discomfort.
FDA Category C. First trimester: Possible increased risk of cardiac defects with oxycodone. Second/third trimester: Chronic use may lead to neonatal opioid withdrawal syndrome; no clear teratogenicity. Acetaminophen is generally safe, but high doses may be hepatotoxic.
First trimester: Associated with increased risk of neural tube defects and cardiovascular malformations; avoid use. Second and third trimesters: Chronic exposure may cause fetal renal toxicity, oligohydramnios, and premature closure of ductus arteriosus. Use only if clearly needed.
Oxycodone: M/P ratio ~0.8-3; present in milk; risk of neonatal sedation. Acetaminophen: M/P ~0.8-1, low risk. Avoid due to oxycodone; consider alternative analgesic.
Paracetamol and hydrocodone are excreted in breast milk. M/P ratio: paracetamol ~1.0, hydrocodone ~1.0-2.0. Use with caution; monitor infant for drowsiness and respiratory depression. Consider risk of infant sedation with long-term use.
Increased clearance of oxycodone in pregnancy may require increased dose; acetaminophen pharmacokinetics unchanged. Adjust based on pain control and withdrawal risk.
Increased clearance in pregnancy may require dose adjustment. Monitor for pain control and adverse effects; no fixed dose change recommended. Consider lower starting dose due to potential fetal risks. Avoid chronic use; taper if possible.
Fixed-dose combination of hydrocodone bitartrate (7.5 mg) and acetaminophen (650 mg). Hydrocodone is a schedule II controlled substance with high abuse potential. Acetaminophen hepatotoxicity risk increases above 3 g/day; prescribe no more than 4 doses per day. Monitor for respiratory depression, especially in opioid-naïve patients. Avoid in severe hepatic impairment. Use with caution in patients with COPD, sleep apnea, or concurrent CNS depressants. Consider naloxone co-prescription if high opioid dose or concurrent benzodiazepine use.
ANEXSIA 5/325 contains hydrocodone 5 mg and acetaminophen 325 mg. Maximum acetaminophen dose from all sources should not exceed 4 g/day in adults; avoid in severe hepatic impairment. Hydrocodone is a Schedule II controlled substance with abuse potential; monitor for respiratory depression, especially in opioid-naive patients. Use with caution in patients with COPD, sleep apnea, or increased intracranial pressure. Consider naloxone co-prescription for high-risk patients. For acute pain, limit duration to 3-7 days.
Take exactly as prescribed; do not increase dose or frequency.,Do not take with alcohol or other medications containing acetaminophen.,May cause drowsiness or dizziness; avoid driving or operating machinery until effects are known.,Store securely out of reach of children and others; dispose of unused tablets properly.,Seek emergency care for difficulty breathing, severe sedation, or signs of allergic reaction.,Do not abruptly stop after prolonged use; withdrawal symptoms may occur.
Take exactly as prescribed; do not increase dose or frequency without consulting your doctor.,Do not consume alcohol or other sedatives (e.g., benzodiazepines) while taking this medication.,Avoid other products containing acetaminophen (e.g., Tylenol, cold remedies) to prevent liver damage.,This medication may cause drowsiness or dizziness; do not drive or operate machinery until you know how it affects you.,Store securely out of reach of others; dispose of unused medication via drug take-back programs.,Seek emergency help if you have trouble breathing, severe drowsiness, or signs of allergic reaction.
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 ANEXSIA 7.5/650 vs ANEXSIA 5/325, answered by our medical review team.
ANEXSIA 7.5/650 is a Opioid Analgesic Combination that works by Hydrocodone is a mu-opioid receptor agonist that inhibits ascending pain pathways and alters pain perception; acetaminophen inhibits cyclooxygenase (COX) enzymes, primarily in the CNS, reducing prostaglandin synthesis and fever.. ANEXSIA 5/325 is a Opioid Analgesic Combination that works by Hydrocodone is a semi-synthetic opioid agonist that binds to mu-opioid receptors in the CNS, inhibiting ascending pain pathways and altering pain perception. Acetaminophen is a para-aminophenol derivative with analgesic and antipyretic effects, primarily through central COX-2 inhibition and activation of descending serotonergic pathways.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between ANEXSIA 7.5/650 and ANEXSIA 5/325 depend on the specific clinical indication. These are both Opioid Analgesic Combination agents and are not directly interchangeable by dose. A physician or clinical pharmacist should guide any therapeutic switching decisions.
The standard adult dose of ANEXSIA 7.5/650 is: 1 tablet orally every 4 to 6 hours as needed; maximum 6 tablets per day.. The standard adult dose of ANEXSIA 5/325 is: 1-2 tablets orally every 4-6 hours as needed for pain; maximum 8 tablets per day.. 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 ANEXSIA 7.5/650 and ANEXSIA 5/325 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. ANEXSIA 7.5/650 is classified as Category C. FDA Category C. First trimester: Possible increased risk of cardiac defects with oxycodone. Second/third trimester: Chronic use may lead to neonatal opioid withdrawal syndrome; no . ANEXSIA 5/325 is classified as Category C. First trimester: Associated with increased risk of neural tube defects and cardiovascular malformations; avoid use. Second and third trimesters: Chronic exposure may cause fetal re. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.