Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
ACETAMINOPHEN AND HYDROCODONE BITARTRATE vs ALLEGRA-D 12 HOUR ALLERGY AND CONGESTION
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Acetaminophen: analgesic and antipyretic effects via inhibition of cyclooxygenase (COX) and activation of descending serotonergic pathways; central action. Hydrocodone: mu-opioid receptor agonist; activates G-protein coupled receptors to modulate pain perception and emotional response.
Fexofenadine is a selective peripheral H1-receptor antagonist; pseudoephedrine is a sympathomimetic amine that directly stimulates alpha-adrenergic receptors, causing vasoconstriction and decongestion.
Moderate to moderately severe pain,Cough suppression (hydrocodone; off-label)
Relief of symptoms associated with seasonal allergic rhinitis and nasal congestion in adults and children 12 years and older
1-2 tablets (containing 5-10 mg hydrocodone and 300-325 mg acetaminophen) orally every 4-6 hours as needed for pain; maximum 8 tablets per day.
Adults and children 12 years and older: 1 tablet (fexofenadine 60 mg/pseudoephedrine 120 mg) orally every 12 hours with water. Do not exceed 2 tablets in 24 hours.
Acetaminophen: 2-3 hours in adults; prolonged in hepatic impairment (up to 5 hours). Hydrocodone: 3.8-4.5 hours (range 3-5 hours) in healthy adults; prolonged in elderly or hepatic/renal impairment. Clinical context: repeated dosing may require extended intervals in renal impairment.
Fexofenadine: 14.4 hours in healthy adults (range 11-15 h); pseudoephedrine: 5-8 hours (p H-dependent urinary excretion may prolong to 14-16 h in alkaline urine).
Acetaminophen: primarily via glucuronidation (UGT1A1, UGT1A6, UGT1A9) and sulfation; minor CYP2E1 oxidation to NAPQI (toxic metabolite). Hydrocodone: CYP3A4 and CYP2D6; N-demethylation to norhydrocodone; O-demethylation to hydromorphone (CYP2D6).
Fexofenadine is minimally metabolized by the liver (≤5% via CYP3A4); pseudoephedrine is partially metabolized by hepatic N-demethylation and undergoes renal excretion.
Acetaminophen: primarily renal excretion of conjugated metabolites (glucuronide and sulfate) with approximately 5% excreted unchanged. Hydrocodone: renal excretion as unchanged drug and metabolites (O-demethylated and N-demethylated); total renal excretion accounts for about 60-70% of dose (parent and metabolites). Biliary/fecal elimination is minimal.
Fexofenadine: 95% excreted unchanged in feces (biliary) and 5% in urine. Pseudoephedrine: 90% excreted unchanged in urine; remainder undergoes hepatic N-demethylation.
Acetaminophen: 10-25% bound, nonspecific binding to albumin. Hydrocodone: 25-50% bound, primarily to albumin and alpha-1-acid glycoprotein.
Fexofenadine: 60-70% bound to plasma proteins (albumin and α1-acid glycoprotein). Pseudoephedrine: negligible binding (<5%).
Acetaminophen: 0.8-1.0 L/kg, indicating distribution into total body water; clinically relevant for loading dose calculations. Hydrocodone: 3.0-4.0 L/kg, suggesting extensive tissue distribution; higher Vd may require higher loading doses but has no clinical target.
Fexofenadine: 3.3 L/kg (large Vd, extensive tissue distribution); pseudoephedrine: 2.6-3.5 L/kg (distributes into body water).
Acetaminophen: oral bioavailability 85-95% (first-pass metabolism minimal). Hydrocodone: oral bioavailability about 25-45% due to first-pass hepatic metabolism; significant interindividual variability.
Fexofenadine: 33% oral bioavailability (first-pass effect minimal, but absorption incomplete). Pseudoephedrine: ~90% oral bioavailability.
GFR 10-50 m L/min: administer every 6 hours; GFR <10 m L/min: administer every 8 hours; avoid in severe impairment due to acetaminophen metabolite accumulation.
Contraindicated in severe renal impairment (Cr Cl < 30 m L/min). For mild to moderate impairment (Cr Cl 30-80 m L/min): fexofenadine dose adjustment recommended (not to exceed 60 mg once daily), but pseudoephedrine accumulation may occur; use alternative product. Not studied in ESRD.
Child-Pugh A: no adjustment; Child-Pugh B: reduce dose by 50% or extend interval; Child-Pugh C: use with caution, avoid if possible, consider alternative therapy.
No dosage adjustment required for mild to moderate hepatic impairment (Child-Pugh A or B). Not studied in severe hepatic impairment (Child-Pugh C); caution.
Dosing based on hydrocodone component: 0.1-0.2 mg/kg/dose every 4-6 hours; maximum daily acetaminophen limit: 75 mg/kg/day; not recommended for children <2 years.
Children under 12 years: not recommended. For children ≥12 years: same as adult dosing: 1 tablet every 12 hours with water.
Initiate at lowest effective dose, typically 1 tablet (2.5-5 mg hydrocodone) every 6 hours; monitor for respiratory depression and acetaminophen toxicity; avoid in frail elderly with hepatic impairment.
Elderly patients may be more sensitive to CNS effects and anticholinergic effects of pseudoephedrine. Not recommended due to increased risk of adverse reactions; consider alternative therapy. If used, monitor closely.
Addiction, abuse, and misuse; life-threatening respiratory depression; accidental ingestion of acetaminophen; neonatal opioid withdrawal syndrome; interaction with alcohol; risk of medication errors.
None.
Hepatotoxicity from acetaminophen overdose; respiratory depression; increased intracranial pressure; CNS depression; elderly/debilitated patients; renal impairment; opioid-induced hyperalgesia; serotonin syndrome; interaction with CNS depressants; risk of adrenal insufficiency; severe hypotension; use in patients with gastrointestinal obstruction; convulsion risk; severe hepatic impairment; urinary retention; acute abdominal conditions; hypothyroidism; prostatic hypertrophy; adrenocortical insufficiency; pregnancy/lactation; pediatric use; geriatric use; renal impairment; hepatic impairment.
Cardiovascular effects: hypertension, arrhythmias, palpitations, tachycardia, myocardial infarction, stroke (especially with pre-existing cardiovascular disease or concomitant use with other sympathomimetics).,Central nervous system stimulation: nervousness, dizziness, insomnia, tremor, seizures (may be exacerbated in patients with seizure disorders).,Increased intraocular pressure: contraindicated in narrow-angle glaucoma.,Urinary retention: use with caution in patients with prostate hypertrophy or obstructive uropathy.,Thyroid disorders: may aggravate hyperthyroidism; use with caution.,Diabetes mellitus: may increase blood glucose; monitor in diabetic patients.,Acute allergic reactions: discontinue if severe hypersensitivity occurs.,Renal impairment: fexofenadine clearance reduced; avoid use in severe renal impairment (Cr Cl <30 m L/min).,Elderly: more sensitive to adverse effects; use with caution.,Drug interactions: MAO inhibitors (hypertensive crisis); antihypertensives (reduced effect); alcohol/CNS depressants (additive effects).
Hypersensitivity to acetaminophen or hydrocodone; significant respiratory depression; acute or severe bronchial asthma; upper airway obstruction; known or suspected gastrointestinal obstruction; paralytic ileus; concomitant use of monoamine oxidase inhibitors (MAOIs) or within 14 days; severe hepatic impairment (acetaminophen toxicity risk); acute alcoholism.
Hypersensitivity to fexofenadine, pseudoephedrine, or any component of the formulation.,Severe hypertension or coronary artery disease.,Narrow-angle glaucoma.,Urinary retention (e.g., due to bladder neck obstruction or prostatic hyperplasia).,Severe renal impairment (Cr Cl <30 m L/min).,Concurrent use or within 14 days of MAO inhibitor therapy (risk of hypertensive crisis).
Avoid alcohol consumption during therapy; ethanol increases acetaminophen hepatotoxicity risk and enhances CNS depression. Grapefruit juice may inhibit CYP2D6 (minor effect) but no significant clinical interaction. No other specific food restrictions.
Avoid alcohol, which can increase drowsiness. Grapefruit juice may reduce absorption of fexofenadine; avoid concurrent intake. Taking with high-fat meal may slow absorption but not affect overall efficacy.
First trimester: Acetaminophen considered low risk; hydrocodone is a pregnancy category C drug. Data from retrospective studies suggest a small increased risk of certain congenital malformations (e.g., neural tube defects, cleft palate) with first trimester opioid use, but absolute risk is low. Second trimester: Low risk as above. Third trimester: Prolonged use of hydrocodone can cause neonatal opioid withdrawal syndrome (NOWS); acetaminophen is safe. Use only if benefit outweighs risk.
FDA Pregnancy Category C. First trimester: Animal studies show teratogenic effects at high doses of fexofenadine; pseudoephedrine may cause reduced uterine blood flow. Second and third trimesters: Risk of uterine contractions and fetal hypoxia due to pseudoephedrine vasoconstriction; avoid in preeclampsia.
Acetaminophen excretion in breast milk is low (M/P ratio ~0.9). Hydrocodone is excreted in small amounts (M/P ratio ~2.1). The relative infant dose is estimated to be 2.5-3.5% of maternal weight-adjusted dose for hydrocodone. Monitor infant for sedation and respiratory depression. Consider benefit to mother and potential neonatal opioid withdrawal if used chronically.
Fexofenadine: low excretion in breast milk (M/P ratio not established); pseudoephedrine: excreted in milk, may cause irritability and sleep disturbances in infants. Use caution, consider risk-benefit.
During pregnancy, increased plasma volume and enhanced hepatic clearance may reduce serum concentrations of both drugs. However, dosing adjustments are not routinely recommended due to risk of undertreatment. Use the lowest effective dose of hydrocodone for the shortest duration. For acetaminophen, maximum daily dose should not exceed 3000 mg to avoid hepatotoxicity.
No specific dose adjustments recommended; use lowest effective dose for shortest duration due to altered pharmacokinetics (increased plasma volume, decreased GFR).
Acetaminophen-hydrocodone is contraindicated in severe respiratory depression, acute or severe bronchial asthma, and known hypersensitivity. Monitor for respiratory depression, especially in elderly or debilitated patients. Avoid use with other acetaminophen-containing products to prevent hepatotoxicity. Hydrocodone is a prodrug metabolized by CYP2D6 to hydromorphone; CYP2D6 ultrarapid metabolizers may experience toxicity. Use with caution in patients with head injury, increased intracranial pressure, or severe hepatic impairment. Naloxone is the reversal agent for opioid effects; acetylcysteine for acetaminophen overdose.
Allegra-D 12 Hour contains fexofenadine (antihistamine) and pseudoephedrine (decongestant). Pseudoephedrine can cause insomnia, so advise taking the last dose early in the evening. Avoid in patients with severe hypertension, coronary artery disease, or narrow-angle glaucoma. Use with caution in hyperthyroidism, diabetes, and prostatic hypertrophy. Do not exceed recommended dose; extended-release formulation must be swallowed whole.
Take exactly as prescribed; do not increase dose or frequency without consulting your doctor.,Avoid alcohol and other CNS depressants (e.g., benzodiazepines, sedatives) as they increase risk of severe drowsiness and respiratory depression.,Do not exceed 4000 mg of acetaminophen per day from all sources; check labels of other medications.,This medication may cause dizziness or drowsiness; avoid driving or operating heavy machinery until you know how it affects you.,Store securely out of reach of others, especially children, as misuse can cause overdose and death.,Do not stop abruptly; withdrawal may occur. Taper under medical supervision.,Contact emergency if you experience trouble breathing, extreme drowsiness, or signs of allergic reaction.,Report any history of substance abuse, as this medication has abuse potential.
Take this medication by mouth with or without food, usually every 12 hours.,Swallow the tablet whole; do not crush, chew, or break it.,Do not take more than 2 tablets in 24 hours.,Avoid taking at bedtime to prevent difficulty sleeping.,Do not take with other products containing pseudoephedrine or other decongestants.,Stop use and ask a doctor if symptoms do not improve within 7 days or are accompanied by fever.,Keep out of reach of children.
"Hydrocodone, an opioid agonist, and scopolamine, an anticholinergic agent, both exhibit central nervous system (CNS) depressant effects. When co-administered, their combined activity can lead to additive CNS depression, resulting in enhanced sedation, respiratory depression, and cognitive impairment. This interaction may also increase the risk of constipation and urinary retention due to additive anticholinergic effects from both drugs."
"Pargyline, a monoamine oxidase inhibitor (MAOI), irreversibly inhibits the metabolism of amines, leading to increased intraneuronal stores of norepinephrine. Hydrocodone, a semisynthetic opioid, can release these stored catecholamines, potentially causing a hypertensive crisis, serotonin syndrome, or CNS excitation. Coadministration may also result in excessive sedation and respiratory depression due to additive CNS depressant effects, requiring immediate clinical attention."
"Hydrocodone, an opioid agonist, and oxprenolol, a non-selective beta-adrenoceptor antagonist, are both central nervous system (CNS) depressants. Their combined use can lead to additive CNS depression, resulting in excessive sedation, respiratory depression, hypotension, and bradycardia. This interaction is particularly dangerous in patients with compromised cardiac or respiratory function, potentially leading to coma or death."
No interactions on record
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about ACETAMINOPHEN AND HYDROCODONE BITARTRATE vs ALLEGRA-D 12 HOUR ALLERGY AND CONGESTION, answered by our medical review team.
ACETAMINOPHEN AND HYDROCODONE BITARTRATE is a Opioid Agonist that works by Acetaminophen: analgesic and antipyretic effects via inhibition of cyclooxygenase (COX) and activation of descending serotonergic pathways; central action. Hydrocodone: mu-opioid receptor agonist; activates G-protein coupled receptors to modulate pain perception and emotional response.. ALLEGRA-D 12 HOUR ALLERGY AND CONGESTION is a Antihistamine-Decongestant Combination that works by Fexofenadine is a selective peripheral H1-receptor antagonist; pseudoephedrine is a sympathomimetic amine that directly stimulates alpha-adrenergic receptors, causing vasoconstriction and decongestion.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between ACETAMINOPHEN AND HYDROCODONE BITARTRATE and ALLEGRA-D 12 HOUR ALLERGY AND CONGESTION 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 HYDROCODONE BITARTRATE is: 1-2 tablets (containing 5-10 mg hydrocodone and 300-325 mg acetaminophen) orally every 4-6 hours as needed for pain; maximum 8 tablets per day.. The standard adult dose of ALLEGRA-D 12 HOUR ALLERGY AND CONGESTION is: Adults and children 12 years and older: 1 tablet (fexofenadine 60 mg/pseudoephedrine 120 mg) orally every 12 hours with water. Do not exceed 2 tablets in 24 hours.. 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 HYDROCODONE BITARTRATE and ALLEGRA-D 12 HOUR ALLERGY AND CONGESTION 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 HYDROCODONE BITARTRATE is classified as Category D/X. First trimester: Acetaminophen considered low risk; hydrocodone is a pregnancy category C drug. Data from retrospective studies suggest a small increased risk of certain congenital. ALLEGRA-D 12 HOUR ALLERGY AND CONGESTION is classified as Category C. FDA Pregnancy Category C. First trimester: Animal studies show teratogenic effects at high doses of fexofenadine; pseudoephedrine may cause reduced uterine blood flow. Second and t. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.