Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
ACETAMINOPHEN AND CODEINE PHOSPHATE vs ALTABAX
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Acetaminophen: centrally acting analgesic and antipyretic, possibly via inhibition of cyclooxygenase (COX) and modulation of cannabinoid receptors. Codeine: prodrug converted to morphine; mu-opioid receptor agonist.
Retapamulin is a pleuromutilin antibiotic that selectively inhibits bacterial protein synthesis by interacting with the 50S ribosomal subunit, specifically at the L3 ribosomal protein and the peptidyl transferase center, thereby preventing peptide bond formation.
Mild to moderate pain,Pain accompanied by fever
FDA-approved for topical treatment of impetigo due to Staphylococcus aureus and Streptococcus pyogenes in patients aged 9 months and older
One or two tablets (acetaminophen 300 mg/codeine 30 mg per tablet) orally every 4-6 hours as needed for pain; maximum 12 tablets daily.
1% ointment applied topically to affected area twice daily for 5 days. Total treatment area should not exceed 100 cm². Maximum single dose is 0.5 g per 100 cm².
Acetaminophen: 2–3 hours (prolonged in hepatic impairment). Codeine: 2.5–3.5 hours; metabolites: morphine 1.5–2.5 hours, codeine-6-glucuronide 3–4 hours. Clinical context: dosing interval every 4–6 hours.
Terminal half-life is approximately 11-14 hours in adults after topical application, supporting twice-daily dosing.
Acetaminophen: primarily glucuronidation and sulfation in liver; minor CYP450 (CYP2E1) to toxic NAPQI. Codeine: CYP2D6 to morphine; CYP3A4 to norcodeine; glucuronidation.
Retapamulin undergoes hepatic metabolism primarily via cytochrome P450 (CYP) isoenzymes, including CYP3A4, and is excreted in feces and urine.
Acetaminophen: renal elimination of conjugated metabolites (glucuronide 60%, sulfate 30%, cysteine/mercapturate <5%), less than 5% unchanged. Codeine: renal elimination of codeine (5–15%), morphine (5–10%), norcodeine (10–20%), and conjugates; 90% excreted in urine within 24 hours.
Retapamulin is primarily eliminated via the fecal route (96.5% of dose), with minimal renal excretion (<0.5% of dose).
Acetaminophen: 10–25% (albumin). Codeine: 7–25% (primarily albumin).
Retapamulin is approximately 94% bound to human plasma proteins, primarily albumin.
Acetaminophen: 0.9 L/kg. Codeine: 3–6 L/kg (extensive tissue distribution).
Volume of distribution after IV administration is approximately 3.1 L/kg, indicating extensive tissue distribution.
Oral: acetaminophen 88% (variable first-pass); codeine 50–60% (first-pass metabolism to morphine, norcodeine, and conjugates).
Systemic bioavailability after topical application is low and highly variable, with mean values <2% in adults.
GFR 30-50 m L/min: administer every 6 hours; GFR 10-29 m L/min: administer every 8 hours; GFR <10 m L/min: administer every 12 hours; hemodialysis: not recommended.
No dose adjustment required for renal impairment as systemic absorption is negligible.
Child-Pugh A: no adjustment; Child-Pugh B: reduce dose by 50% and extend interval to every 8 hours; Child-Pugh C: contraindicated.
No dose adjustment required for hepatic impairment as systemic absorption is negligible.
For children ≥12 years: acetaminophen 10-15 mg/kg/dose and codeine 0.5-1 mg/kg/dose orally every 4-6 hours; maximum acetaminophen 75 mg/kg/day, codeine 6 mg/kg/day. For children <12 years: not recommended due to codeine safety concerns.
Children 9 months and older: Apply 1% ointment to affected area twice daily for 5 days. Maximum treatment area 100 cm². For children under 9 months: safety and efficacy not established.
Start with lowest effective dose; acetaminophen component maximum 3 g/day; consider reduced codeine dose (e.g., 15 mg) due to increased sensitivity and risk of respiratory depression; extend dosing interval to every 6-8 hours.
No specific dose adjustment required. Use same as adult dosing due to minimal systemic absorption.
Risk of medication errors: confusion between milligram and milliliter doses, and between codeine and acetaminophen components. Contraindicated for postoperative pain management in children following tonsillectomy/adenoidectomy due to risk of respiratory depression and death.
No black box warnings.
Hepatotoxicity (acetaminophen overdose); respiratory depression; drug dependence; ultra-rapid metabolizers of codeine (CYP2D6) leading to morphine toxicity; concomitant CNS depressants; use in pediatric patients; avoid alcohol.
Not for use on mucous membranes (e.g., eyes, mouth, vagina).,May cause application site reactions (e.g., pruritus, erythema, pain).,Clostridium difficile-associated diarrhea (CDAD) has been reported with nearly all antibacterial agents, including retapamulin.,Prolonged use may result in overgrowth of nonsusceptible organisms.
Hypersensitivity to acetaminophen or codeine; severe respiratory depression; acute or severe asthma; paralytic ileus; post-operative pain management in children after tonsillectomy/adenoidectomy; breastfeeding (in ultra-rapid metabolizers); concomitant MAOIs.
Hypersensitivity to retapamulin or any component of the formulation.
Avoid alcohol; high-fat meals may delay absorption but not clinically significant.
None known. Topical application with negligible systemic absorption; no dietary restrictions.
Acetaminophen is considered low risk in all trimesters at therapeutic doses; chronic high doses may be associated with adverse outcomes. Codeine is associated with risk of respiratory depression and neonatal withdrawal if used near term; may cause neural tube defects and other malformations with first-trimester exposure, but data are conflicting. Use lowest effective dose for shortest duration.
No adequate and well-controlled studies in pregnant women. Animal studies: oral doses up to 50 mg/kg/day in rats (0.8 times MRHD based on AUC) and 40 mg/kg/day in rabbits (1.6 times MRHD) showed no fetal harm. However, systemic absorption after topical application is minimal, so fetal exposure is negligible. Risk cannot be ruled out; classify as pregnancy category B.
Acetaminophen is excreted into breast milk in low amounts (M/P ratio ~0.91-1.42) and is considered compatible with breastfeeding. Codeine is also excreted in breast milk; risk of infant opioid toxicity depends on maternal CYP2D6 phenotype. Ultra-rapid metabolizers may produce higher morphine levels. Use with caution, avoid in known CYP2D6 ultra-rapid metabolizers, and monitor infant for sedation and respiratory depression.
Not known if retapamulin is excreted in human milk. Systemic absorption is negligible after topical use, so risk to infant is likely low. M/P ratio not determined. Caution if applied to breast area to avoid infant ingestion.
No routine dose adjustment needed for acetaminophen. Codeine pharmacokinetics are altered in pregnancy: increased clearance and volume of distribution may require dose adjustment; however, due to variability in CYP2D6 metabolism, individualize dosing and monitor for efficacy and toxicity. Avoid codeine in pregnancy unless alternative analgesics are ineffective.
No dose adjustment needed. Pharmacokinetics unchanged as systemic absorption is minimal (<1%) and not affected by pregnancy. Standard dosing: apply thin layer to affected area twice daily for 5 days.
For acute pain, limit codeine to 3 days; avoid in children under 12 due to CYP2D6 ultra-rapid metabolizer risk of fatal respiratory depression; monitor for constipation; assess liver function for acetaminophen hepatotoxicity; use with caution in renal impairment.
Retapamulin (Altabax) is a topical pleuromutilin antibiotic indicated for impetigo due to S. aureus or S. pyogenes. Apply to lesions twice daily for 5 days. Avoid contact with eyes, mouth, or mucous membranes. No systemic absorption significant; safe for use in children ≥9 months. Do not use on open wounds or burns. Monitor for local irritation; discontinue if hypersensitivity occurs.
Take exactly as prescribed; do not exceed 4000 mg acetaminophen per day.,Avoid alcohol while taking this medication.,Do not use with other acetaminophen-containing products.,May cause dizziness or drowsiness; avoid driving until you know how you react.,Common side effects include constipation, nausea, and drowsiness.,Seek emergency if signs of allergic reaction or difficulty breathing occur.
Apply a thin layer to the affected area twice daily for 5 days, even if symptoms improve.,Wash hands before and after application unless treating hand lesions.,Do not cover the area with bandages unless instructed by your doctor.,Avoid getting the ointment in your eyes, nose, mouth, or on vaginal area.,Stop use and inform your doctor if you develop severe irritation, redness, or swelling.,Store at room temperature away from heat and moisture.
"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."
No interactions on record
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about ACETAMINOPHEN AND CODEINE PHOSPHATE vs ALTABAX, answered by our medical review team.
ACETAMINOPHEN AND CODEINE PHOSPHATE is a Opioid Agonist that works by Acetaminophen: centrally acting analgesic and antipyretic, possibly via inhibition of cyclooxygenase (COX) and modulation of cannabinoid receptors. Codeine: prodrug converted to morphine; mu-opioid receptor agonist.. ALTABAX is a Topical Antibiotic that works by Retapamulin is a pleuromutilin antibiotic that selectively inhibits bacterial protein synthesis by interacting with the 50S ribosomal subunit, specifically at the L3 ribosomal protein and the peptidyl transferase center, thereby preventing peptide bond formation.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between ACETAMINOPHEN AND CODEINE PHOSPHATE and ALTABAX 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 ACETAMINOPHEN AND CODEINE PHOSPHATE is: One or two tablets (acetaminophen 300 mg/codeine 30 mg per tablet) orally every 4-6 hours as needed for pain; maximum 12 tablets daily.. The standard adult dose of ALTABAX is: 1% ointment applied topically to affected area twice daily for 5 days. Total treatment area should not exceed 100 cm². Maximum single dose is 0.5 g per 100 cm².. 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 ACETAMINOPHEN AND CODEINE PHOSPHATE and ALTABAX 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. ACETAMINOPHEN AND CODEINE PHOSPHATE is classified as Category D/X. Acetaminophen is considered low risk in all trimesters at therapeutic doses; chronic high doses may be associated with adverse outcomes. Codeine is associated with risk of respirat. ALTABAX is classified as Category C. No adequate and well-controlled studies in pregnant women. Animal studies: oral doses up to 50 mg/kg/day in rats (0.8 times MRHD based on AUC) and 40 mg/kg/day in rabbits (1.6 time. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.