Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
TYLENOL W/ CODEINE NO. 4 vs HYDROCODONE BITARTRATE
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: June 2026 · OpiCalc Medical Review Team
Codeine is a prodrug that undergoes O-demethylation by CYP2D6 to morphine, which acts as a μ-opioid receptor agonist, inhibiting adenylate cyclase and modulating neurotransmitter release in the CNS. Acetaminophen inhibits cyclooxygenase (COX) enzymes, primarily in the CNS, reducing prostaglandin synthesis and modulating pain perception.
Hydrocodone is an opioid agonist that binds to mu-opioid receptors in the central nervous system, inhibiting ascending pain pathways and altering pain perception.
Management of mild to moderate pain where an opioid analgesic is needed
Management of severe pain requiring an opioid analgesic,Cough suppression (off-label)
One or 2 tablets (acetaminophen 300 mg-codeine 60 mg per tablet) orally every 4 hours as needed for pain; maximum 12 tablets per day.
Adults: 5-10 mg orally every 4-6 hours as needed for pain; maximum 60 mg/day.
Codeine: Terminal half-life of 2.5-3.5 hours; however, its active metabolite morphine has a half-life of 1.5-2 hours, and morphine-6-glucuronide (M6G) has a half-life of 2-4 hours. Acetaminophen: Terminal half-life of 2-3 hours in adults; prolonged in hepatic impairment (up to 4-5 hours) or overdose (4-12 hours). Clinically, duration of analgesic effect is approximately 4-6 hours.
Terminal elimination half-life is approximately 3.5-4 hours in healthy adults. In patients with hepatic impairment (Child-Pugh Class B), half-life may be prolonged to ~6 hours. In renal impairment (Cr Cl <30 m L/min), half-life may be extended by 30-50%.
e GFR 30-50 m L/min: use with caution, reduce dose by 25%. e GFR <30 m L/min: not recommended due to risk of accumulation and respiratory depression.
e GFR 30-50 m L/min: reduce dose by 25%; e GFR 15-29 m L/min: reduce dose by 50%; e GFR <15 m L/min: avoid use or use with extreme caution, consider alternative.
WARNING: ADDICTION, ABUSE, AND MISUSE; LIFE-THREATENING RESPIRATORY DEPRESSION; ACCIDENTAL INGESTION; ULTRA-RAPID METABOLISM OF CODEINE AND OTHER RISK FACTORS FOR LIFE-THREATENING RESPIRATORY DEPRESSION IN CHILDREN; NEONATAL OPIOID WITHDRAWAL SYNDROME; HEPATOTOXICITY; INTERACTION WITH ALCOHOL; RISKS FROM CONCOMITANT USE WITH BENZODIAZEPINES OR OTHER CNS DEPRESSANTS; RISK OF MEDICATION ERRORS.
Pregnancy Category C prior to 2015; current data insufficient for definitive risk. Acetaminophen: no consistent evidence of major malformations; codeine: opioid use in first trimester associated with small increased risk of neural tube defects (OR 1.1-1.3); third trimester use may cause neonatal opioid withdrawal syndrome (NOWS) and respiratory depression at delivery.
First trimester: Limited data; association with neural tube defects and other malformations in some studies but not confirmed. Second and third trimesters: Prolonged use can cause neonatal opioid withdrawal syndrome; high doses near term may lead to respiratory depression in the neonate. Avoid chronic use; use lowest effective dose for shortest duration.
Each tablet contains acetaminophen 300 mg and codeine phosphate 60 mg. Maximum acetaminophen dose: 4 g/day; avoid other acetaminophen-containing products. Codeine is a prodrug; CYP2D6 poor metabolizers may have reduced efficacy, while ultra-rapid metabolizers risk toxicity. Monitor for respiratory depression, especially in opioid-naive patients. Use with caution in patients with liver impairment or G6PD deficiency.
Hydrocodone bitartrate is a semisynthetic opioid agonist with antitussive properties. Use with extreme caution in patients with respiratory compromise, head injury, or COPD. Metabolism primarily via CYP3A4 and CYP2D6; coadministration with CYP3A4 inhibitors (e.g., ketoconazole) or inducers (e.g., rifampin) significantly alters serum levels. Consider QT prolongation risk at high doses. Naloxone should be available for overdose reversal. Avoid in patients with paralytic ileus or known hypersensitivity.
No interactions on record
No interactions on record
Common clinical questions about TYLENOL W/ CODEINE NO. 4 vs HYDROCODONE BITARTRATE, answered by our medical review team.
TYLENOL W/ CODEINE NO. 4 is a Opioid Agonist that works by Codeine is a prodrug that undergoes O-demethylation by CYP2D6 to morphine, which acts as a μ-opioid receptor agonist, inhibiting adenylate cyclase and modulating neurotransmitter release in the CNS. Acetaminophen inhibits cyclooxygenase (COX) enzymes, primarily in the CNS, reducing prostaglandin synthesis and modulating pain perception.. HYDROCODONE BITARTRATE is a Opioid Agonist that works by Hydrocodone is an opioid agonist that binds to mu-opioid receptors in the central nervous system, inhibiting ascending pain pathways and altering pain perception.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between TYLENOL W/ CODEINE NO. 4 and HYDROCODONE BITARTRATE 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 TYLENOL W/ CODEINE NO. 4 is: One or 2 tablets (acetaminophen 300 mg-codeine 60 mg per tablet) orally every 4 hours as needed for pain; maximum 12 tablets per day.. The standard adult dose of HYDROCODONE BITARTRATE is: Adults: 5-10 mg orally every 4-6 hours as needed for pain; maximum 60 mg/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 TYLENOL W/ CODEINE NO. 4 and HYDROCODONE BITARTRATE 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. TYLENOL W/ CODEINE NO. 4 is classified as Category D/X. Pregnancy Category C prior to 2015; current data insufficient for definitive risk. Acetaminophen: no consistent evidence of major malformations; codeine: opioid use in first trimes. HYDROCODONE BITARTRATE is classified as Category D/X. First trimester: Limited data; association with neural tube defects and other malformations in some studies but not confirmed. Second and third trimesters: Prolonged use can cause . Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.
Codeine: metabolized by CYP2D6 to morphine (active), CYP3A4 to norcodeine, and glucuronidation. Acetaminophen: extensively metabolized in the liver via conjugation (glucuronidation, sulfation) and minor oxidation by CYP2E1 to N-acetyl-p-benzoquinone imine (NAPQI), which is detoxified by glutathione.
Primarily metabolized by CYP2D6 and CYP3A4 to hydromorphone and other metabolites; undergoes O-demethylation and N-demethylation.
Codeine and its metabolites (including morphine, morphine-6-glucuronide, and norcodeine) are primarily excreted renally. Approximately 90% of a codeine dose is excreted in urine within 24 hours, with 5-15% as free codeine, 5-13% as free morphine, 40-60% as codeine conjugates, and 5-10% as morphine conjugates. Fecal excretion accounts for less than 5%. Acetaminophen is primarily metabolized in the liver to glucuronide and sulfate conjugates; about 85% of a dose is excreted renally as conjugates within 24 hours, with 2-4% excreted unchanged. Minor biliary/fecal elimination occurs for both drugs.
Renal excretion of metabolites (primarily hydromorphone and norhydrocodone) accounts for approximately 99% of elimination, with less than 1% excreted unchanged. Biliary/fecal elimination is negligible.
Codeine: Approximately 20-40% bound to plasma proteins (primarily albumin). Morphine: 20-35% bound. Acetaminophen: 10-25% bound to albumin. Binding is minimal and generally not clinically significant.
Approximately 20-30% bound to plasma proteins, primarily albumin.
Codeine: Vd approximately 3-4 L/kg (range 2.5-5 L/kg). Acetaminophen: Vd approximately 0.9 L/kg (range 0.7-1.0 L/kg). Codeine's larger Vd indicates extensive tissue distribution; acetaminophen distributes evenly throughout body fluids.
Approximately 3-4 L/kg, indicating extensive extravascular distribution. Higher Vd in women and elderly due to increased body fat.
Oral: Codeine bioavailability is approximately 50-60% (first-pass metabolism). Acetaminophen bioavailability is 70-90% (absorbed rapidly from GI tract; first-pass metabolism minimal). Rectal bioavailability of acetaminophen is approximately 80-90% of oral.
Oral bioavailability is approximately 70% (range 60-80%). Intranasal bioavailability is comparable to oral. Rectal and sublingual routes have not been well characterized.
Child-Pugh class A: caution, maximum 2 tablets per dose; class B or C: contraindicated.
Child-Pugh Class A: no adjustment necessary; Child-Pugh Class B: reduce dose by 50%; Child-Pugh Class C: avoid use.
Not recommended for children under 12 years. For ages 12-18: weight-based codeine dosing 0.5-1 mg/kg/dose every 4-6 hours (max 60 mg/dose); acetaminophen 15 mg/kg/dose every 4-6 hours (max 75 mg/kg/day). Use lowest effective dose.
Children ≥2 years: 0.1-0.2 mg/kg/dose every 4-6 hours as needed; maximum single dose 10 mg; maximum daily dose 40 mg. Not recommended for children <2 years.
Initiate at half the adult dose (1 tablet) every 4 hours due to increased sensitivity to opioids and acetaminophen hepatotoxicity; maximum 8 tablets per day. Monitor renal and hepatic function closely.
Initiate at lowest effective dose, typically 2.5-5 mg every 6 hours; monitor for respiratory depression and constipation; titrate cautiously due to increased sensitivity and potential for renal impairment.
Addiction, abuse, and misuse; respiratory depression; neonatal opioid withdrawal syndrome; risks from concomitant use with benzodiazepines or other CNS depressants.
Avoid alcohol and foods containing alcohol (e.g., desserts, sauces) due to increased risk of hepatotoxicity and CNS depression. No specific food restrictions otherwise.
Avoid grapefruit and grapefruit juice as they inhibit CYP3A4 and may increase hydrocodone levels. High-fat meals may delay absorption of immediate-release formulations. No significant interaction with other foods.
Acetaminophen is compatible (low levels in milk). Codeine is present in milk; M/P ratio approximately 2:1 (morphine). Caution: ultra-rapid CYP2D6 metabolizers may produce high morphine levels leading to infant toxicity. Use lowest effective dose for shortest duration; monitor infant for drowsiness, difficulty breathing.
Hydrocodone is excreted into breast milk; M/P ratio approximately 2:1 based on limited data. Relative infant dose estimated at 2-3% of maternal weight-adjusted dose. Monitor infant for drowsiness, respiratory depression, and constipation. Benefit of breastfeeding should outweigh potential risk; consider alternative analgesics with better safety profile.
No specific dose adjustment recommended for acetaminophen; codeine pharmacokinetics altered in pregnancy (increased clearance, decreased half-life). Avoid codeine in pregnancy if possible; if used, lowest effective dose for shortest duration. Consider alternative analgesics (e.g., acetaminophen alone). Postpartum: resume standard dosing.
Pharmacokinetic changes in pregnancy include increased renal clearance and volume of distribution, potentially reducing serum levels. However, no established dose adjustment guidelines; use lowest effective dose and monitor for efficacy/withdrawal. Avoid sustained-release formulations; use immediate-release for shortest duration.
Do not exceed 12 tablets in 24 hours due to acetaminophen content.,Avoid alcohol while taking this medication.,This drug may cause drowsiness; do not drive or operate machinery until you know how it affects you.,Contact your doctor if you experience signs of allergic reaction (rash, difficulty breathing) or liver injury (yellowing of skin/eyes, dark urine).,Do not take with other products containing acetaminophen (e.g., Tylenol, cold medicines).,Codeine can be habit-forming; use only as prescribed.,Women who are breastfeeding should consult their doctor; codeine can pass into breast milk.
Take exactly as prescribed; do not increase dose or frequency without consulting your doctor.,Avoid alcohol and other central nervous system depressants (e.g., benzodiazepines) as this may cause severe sedation or respiratory depression.,Do not crush, chew, or break extended-release tablets; swallow whole.,Store securely out of reach of children and pets; dispose of unused medication via take-back programs.,May cause constipation; increase fluid and fiber intake; consider stool softeners if needed.,Report any difficulty breathing, severe drowsiness, or signs of allergic reaction (rash, swelling) immediately.,Do not suddenly stop taking this medication without medical supervision to avoid withdrawal symptoms.