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 ACTIFED W/ CODEINE
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: June 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.
Codeine is a prodrug that is metabolized to morphine, which acts as a mu-opioid receptor agonist; triprolidine is an H1 receptor antagonist. The combination produces antitussive and antihistamine effects.
Mild to moderate pain,Pain accompanied by fever
Symptomatic relief of cough and upper respiratory symptoms associated with allergy or cold
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.
Adults: 10 m L orally every 4-6 hours as needed, not to exceed 4 doses in 24 hours. Each 10 m L contains 10 mg codeine, 4 mg triprolidine, 60 mg pseudoephedrine.
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.
Codeine: 2.5-4 hours; pseudoephedrine: 5-8 hours; triprolidine: 3-6 hours. Context: Codeine half-life prolonged in hepatic impairment and CYP2D6 poor metabolizers; pseudoephedrine half-life increased with alkaline urine.
Acetaminophen: primarily glucuronidation and sulfation in liver; minor CYP450 (CYP2E1) to toxic NAPQI. Codeine: CYP2D6 to morphine; CYP3A4 to norcodeine; glucuronidation.
Codeine is metabolized primarily via glucuronidation and O-demethylation to morphine by CYP2D6, and N-demethylation to norcodeine by CYP3A4. Triprolidine is metabolized by hepatic CYP450 enzymes.
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.
Renal: 60-80% (codeine and metabolites, primarily as codeine-6-glucuronide, norcodeine, and morphine); unchanged codeine <10%. Fecal: <10%. Biliary: minor.
Acetaminophen: 10–25% (albumin). Codeine: 7–25% (primarily albumin).
Codeine: 7-25% (primarily albumin); pseudoephedrine: negligible (<5%); triprolidine: approximately 85% (mainly albumin).
Acetaminophen: 0.9 L/kg. Codeine: 3–6 L/kg (extensive tissue distribution).
Codeine: 3-6 L/kg; pseudoephedrine: 2.5-3.5 L/kg; triprolidine: 2-5 L/kg. Indicates extensive tissue distribution.
Oral: acetaminophen 88% (variable first-pass); codeine 50–60% (first-pass metabolism to morphine, norcodeine, and conjugates).
Codeine: 50-70% (oral); pseudoephedrine: 100% (oral); triprolidine: approximately 50% (oral) due to first-pass metabolism.
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.
GFR 30-59 m L/min: administer every 6 hours; GFR <30 m L/min: administer every 12 hours or avoid use due to risk of accumulation of codeine and pseudoephedrine; hemodialysis: not recommended.
Child-Pugh A: no adjustment; Child-Pugh B: reduce dose by 50% and extend interval to every 8 hours; Child-Pugh C: contraindicated.
Child-Pugh A (mild): no adjustment; Child-Pugh B (moderate): reduce dose by 50% or extend interval to every 8 hours; Child-Pugh C (severe): avoid use due to risk of central nervous system depression.
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.
Not recommended in children <12 years due to risk of respiratory depression. For children ≥12 years: 10 m L orally every 4-6 hours as needed, max 4 doses in 24 hours. Weight-based dosing 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.
Start at lower dose (e.g., 5 m L orally every 6 hours) due to increased sensitivity to anticholinergic and sedative effects; monitor for confusion, urinary retention, and hypotension.
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.
WARNING: RISKS FROM CONCOMITANT USE WITH BENZODIAZEPINES OR OTHER CNS DEPRESSANTS; ADDICTION, ABUSE, AND MISUSE; RISK EVALUATION AND MITIGATION STRATEGY (REMS); LIFE-THREATENING RESPIRATORY DEPRESSION; ACCIDENTAL INGESTION; NEONATAL OPIOID WITHDRAWAL SYNDROME; CYP2D6 GENETIC VARIABILITY; INTERACTION WITH ALCOHOL; RISKS FROM CONCOMITANT USE OF CYP3A4 INHIBITORS; RISKS IN PATIENTS WITH GASTROINTESTINAL CONDITIONS; RISKS OF USE IN PATIENTS WITH ASTHMA OR OTHER RESPIRATORY DISEASE; LABEL FOR INFANTS AND CHILDREN.
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.
Addiction, abuse, and misuse,Life-threatening respiratory depression,Neonatal opioid withdrawal syndrome,Risks from concomitant use with benzodiazepines or other CNS depressants,CYP2D6 genetic variability (ultrarapid metabolizers),Accidental ingestion,Interaction with alcohol,Use in patients with gastrointestinal conditions,Use in patients with asthma or other respiratory disease,Avoid use in children <12 years
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 codeine, triprolidine, or any component,Children <12 years,Postoperative management in children <18 years after tonsillectomy and/or adenoidectomy,Significant respiratory depression,Acute or severe bronchial asthma,Concurrent use of monoamine oxidase inhibitors (MAOIs) or within 14 days,Paralytic ileus,Known CYP2D6 ultrarapid metabolizers
Avoid alcohol; high-fat meals may delay absorption but not clinically significant.
Avoid grapefruit and grapefruit juice as they may increase codeine levels and risk of adverse effects. High-tyramine foods (aged cheese, cured meats, fermented products) may interact with pseudoephedrine, potentially causing hypertensive crisis. Alcohol is contraindicated due to additive CNS depression.
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.
First trimester: Codeine is associated with increased risk of congenital malformations (OR 1.24–2.0), particularly cardiac defects, with a dose-response relationship. Triprolidine and pseudoephedrine are generally considered low risk, but pseudoephedrine may be associated with gastroschisis (OR 1.8). Second trimester: Codeine may cause fetal dependence; pseudoephedrine may reduce uteroplacental blood flow. Third trimester: Codeine can cause neonatal opioid withdrawal syndrome (NOWS) and respiratory depression at delivery; pseudoephedrine may exacerbate pregnancy-induced hypertension. Overall, avoid in pregnancy for non-severe indications.
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.
Codeine and pseudoephedrine are excreted into breast milk. M/P ratio for codeine is ~2.5; for pseudoephedrine, ~2.6–3.5. Use is contraindicated in breastfeeding due to risk of neonatal opioid toxicity (especially in CYP2D6 ultra-rapid metabolizers) and potential irritability/poor feeding from pseudoephedrine. Triprolidine has limited data but is considered compatible in low doses.
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 specific dose adjustments are established; however, due to increased renal clearance of pseudoephedrine in pregnancy, standard doses may be less effective. Codeine metabolism via CYP2D6 is variably affected by pregnancy (increased clearance ≈30–50% in second/third trimester), potentially requiring dose titration. Avoid use entirely in pregnancy; use alternative agents if needed.
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.
Actifed w/ Codeine combines triprolidine, pseudoephedrine, and codeine. Due to codeine's prodrug metabolism via CYP2D6, ultra-rapid metabolizers risk toxicity; contraindicated in children <12 years, post-tonsillectomy/adenoidectomy, and breastfeeding. Pseudoephedrine may cause hypertensive crisis with MAOIs. Triprolidine's anticholinergic effects exacerbate glaucoma, urinary retention, and cognitive impairment in elderly.
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.
Do not exceed recommended dose; risk of serious breathing problems, especially in children.,Avoid alcohol and other CNS depressants (e.g., benzodiazepines, opioids) as they increase sedation and respiratory depression risk.,Store securely; codeine carries risk of dependence and misuse.,If pregnant or breastfeeding, consult prescriber; do not use while breastfeeding due to infant toxicity risk.,May cause drowsiness; avoid driving or operating heavy machinery until effects are known.,Inform healthcare provider of all medications, especially MAOIs (within 14 days), antidepressants, or blood pressure medications.,Discontinue and seek medical help if symptoms of allergic reaction (rash, itching, swelling, severe dizziness, trouble breathing) occur.,Use caution with high blood pressure, thyroid problems, diabetes, or enlarged prostate.
"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."
"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 ACETAMINOPHEN AND CODEINE PHOSPHATE vs ACTIFED W/ CODEINE, 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.. ACTIFED W/ CODEINE is a Opioid Agonist that works by Codeine is a prodrug that is metabolized to morphine, which acts as a mu-opioid receptor agonist; triprolidine is an H1 receptor antagonist. The combination produces antitussive and antihistamine effects.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between ACETAMINOPHEN AND CODEINE PHOSPHATE and ACTIFED W/ CODEINE 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 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 ACTIFED W/ CODEINE is: Adults: 10 m L orally every 4-6 hours as needed, not to exceed 4 doses in 24 hours. Each 10 m L contains 10 mg codeine, 4 mg triprolidine, 60 mg pseudoephedrine.. 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 ACETAMINOPHEN AND CODEINE PHOSPHATE and ACTIFED W/ CODEINE. Codeine, a prodrug converted to morphine via CYP2D6, and metyrosine, a tyrosine hydroxylase inhibitor, synergistically depress the central nervous system. Codeine's mu-opioid receptor agonism and metyrosine's reduction of catecholamine synthesis lead to enhanced sedation, respiratory depression, and hypotension. Clinically, patients may experience excessive drowsiness, confusion, or respiratory compromise, particularly at higher doses or in vulnerable populations. Consult your prescriber before combining these medications.
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. ACTIFED W/ CODEINE is classified as Category D/X. First trimester: Codeine is associated with increased risk of congenital malformations (OR 1.24–2.0), particularly cardiac defects, with a dose-response relationship. Triprolidine . Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.