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 FARESTON
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.
Selective estrogen receptor modulator (SERM) that competitively binds to estrogen receptors, exerting antiestrogenic effects in breast tissue.
Moderate to moderately severe pain,Cough suppression (hydrocodone; off-label)
FDA-approved for the treatment of metastatic breast cancer in postmenopausal women with estrogen receptor-positive tumors,Off-label: treatment of advanced breast cancer in premenopausal women in combination with ovarian suppression
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.
60 mg orally once daily.
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.
The terminal elimination half-life of toremifene is approximately 5 days (range 2-10 days). The half-life of its main metabolite, N-desmethyltoremifene, is about 11 days. This long half-life supports once-daily dosing.
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).
Primarily hepatic via CYP3A4 and CYP1A2; undergoes glucuronidation; active metabolite N-desmethyltoremifene
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.
FARESTON (toremifene) is extensively metabolized in the liver. Excretion is primarily fecal (approximately 70%) with renal excretion accounting for less than 10% of the dose as unchanged drug and metabolites.
Acetaminophen: 10-25% bound, nonspecific binding to albumin. Hydrocodone: 25-50% bound, primarily to albumin and alpha-1-acid glycoprotein.
Toremifene is >99% bound to plasma proteins, primarily albumin.
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.
The apparent volume of distribution (Vd) is approximately 580 L (about 8 L/kg for a 70 kg individual), indicating extensive tissue distribution.
Acetaminophen: oral bioavailability 85-95% (first-pass metabolism minimal). Hydrocodone: oral bioavailability about 25-45% due to first-pass hepatic metabolism; significant interindividual variability.
Oral bioavailability of toremifene is not precisely determined but is estimated to be nearly 100% based on absorption and first-pass metabolism studies.
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.
No dose adjustment required for GFR ≥30 m L/min; insufficient data for GFR <30 m L/min.
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.
Contraindicated in Child-Pugh class C; use with caution in class A or B without specific dose reduction guidelines.
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.
Safety and efficacy not established; no recommended dose.
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.
No specific dose adjustment; monitor renal function and electrolyte balance.
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.
QT interval prolongation,Hypercalcemia in patients with bone metastases,Endometrial hyperplasia/cancer risk,Thromboembolic events,Ocular toxicity (dose-dependent retinopathy),Tumor flare
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 toremifene or any excipients,History of thromboembolic disease,Pre-existing endometrial hyperplasia,Patients with long QT syndrome or concurrent use of QT-prolonging drugs
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 grapefruit and grapefruit juice due to CYP3A4 inhibition, which can increase toremifene levels and risk of adverse effects. No other significant food interactions known. Take with or without food.
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.
Pregnancy Category D. First trimester: Risk of fetal harm, including spontaneous abortion and congenital malformations (e.g., craniofacial, cardiac). Second and third trimesters: Potential for fetal hypothalamic-pituitary-gonadal axis disruption, ambiguous genitalia in female fetuses, and other adverse effects based on animal studies.
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.
Not recommended during breastfeeding. Toremifene may be excreted in human milk; M/P ratio not established. Potential for serious adverse reactions in nursing infants, including hormonal disruption.
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 established dose adjustments; use contraindicated in pregnancy. Pharmacokinetic changes (increased volume of distribution, altered clearance) may require empirical dose reduction if used inadvertently, but no specific guidelines exist. Avoid use.
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.
FARESTON (toremifene) is a selective estrogen receptor modulator (SERM) used for metastatic breast cancer in postmenopausal women with estrogen receptor-positive tumors. Unlike tamoxifen, toremifene has a longer half-life (about 5 days) and may have a lower risk of thromboembolic events. Monitor liver function tests regularly due to potential hepatotoxicity. Prolongation of QT interval has been reported; avoid in patients with pre-existing QTc prolongation or with other QT-prolonging drugs. Use with caution in patients with endometrial hyperplasia or history of thromboembolic disease.
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 exactly as prescribed, usually once daily with or without food.,You may experience hot flashes, nausea, or sweating; these are common and usually manageable.,Report any unusual vaginal bleeding, discharge, or pelvic pain to your doctor immediately.,Watch for signs of blood clots such as leg pain/swelling, sudden chest pain, or shortness of breath.,Avoid grapefruit and grapefruit juice while on this medication as they may increase side effects.,Use non-hormonal contraception if you are still able to become pregnant; toremifene can harm a fetus.,Do not stop or change your dose without consulting your healthcare provider.
"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 FARESTON, 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.. FARESTON is a Selective Estrogen Receptor Modulator that works by Selective estrogen receptor modulator (SERM) that competitively binds to estrogen receptors, exerting antiestrogenic effects in breast tissue.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between ACETAMINOPHEN AND HYDROCODONE BITARTRATE and FARESTON 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 FARESTON is: 60 mg orally once daily.. 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 FARESTON 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. FARESTON is classified as Category C. Pregnancy Category D. First trimester: Risk of fetal harm, including spontaneous abortion and congenital malformations (e.g., craniofacial, cardiac). Second and third trimesters: P. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.