Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
TUXARIN ER vs CODOXY
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
TUXARIN ER contains dextromethorphan, an NMDA receptor antagonist and sigma-1 receptor agonist, and bupropion, a norepinephrine and dopamine reuptake inhibitor. The combination is thought to modulate glutamatergic neurotransmission and enhance dopaminergic and noradrenergic signaling.
Oxycodone is a full opioid agonist with relative selectivity for the mu-opioid receptor, although it can bind to other opioid receptors at higher doses. The principal therapeutic action of oxycodone is analgesia. Like all full opioid agonists, there is no ceiling effect for analgesia. Oxycodone is combined with aspirin to provide additive analgesic effects.
Major depressive disorder (FDA-approved as Auvelity),Treatment-resistant depression (off-label)
Management of moderate to moderately severe pain where the use of an opioid analgesic is appropriate
1 tablet orally every 12 hours; each tablet contains chlorpheniramine maleate 8 mg and phenylephrine HCl 20 mg.
1-2 capsules orally every 4-6 hours as needed for pain, not to exceed 8 capsules per day. Each capsule contains 5 mg hydrocodone bitartrate and 325 mg acetaminophen.
The terminal elimination half-life (t1/2) of chlorpheniramine is approximately 14–25 h in adults, allowing twice-daily dosing. Pseudoephedrine has a shorter t1/2 of 5–8 h in normal renal function, but the ER formulation maintains therapeutic levels for 12 h. In renal impairment, pseudoephedrine half-life prolongs significantly, requiring dose adjustment.
Terminal half-life is 3.5 hours in patients with normal renal function; extends to 5-8 hours in moderate renal impairment.
Bupropion is extensively metabolized via CYP2B6 to hydroxybupropion, while dextromethorphan is metabolized primarily by CYP2D6 to dextrorphan. Both are further metabolized by other enzymes.
Oxycodone is metabolized by CYP3A4 and CYP2D6. N-demethylation to noroxycodone (via CYP3A4) is the primary metabolic pathway. CYP2D6-mediated O-demethylation to oxymorphone is a minor pathway but produces a more potent metabolite.
TUXARIN ER is a combination antihistamine/decongestant. The antihistamine component (e.g., chlorpheniramine) is extensively metabolized via CYP450; its metabolites and parent drug (∼68% over 48 h) appear in urine as unchanged drug and metabolites. The decongestant (e.g., pseudoephedrine) is primarily excreted unchanged in urine (∼70–90%) with the remainder metabolized in liver; renal elimination is p H-dependent, with acidic urine increasing excretion. Fecal elimination is negligible (<5%).
Renal excretion of unchanged drug accounts for approximately 70% of elimination; biliary/fecal excretion accounts for 30%.
Chlorpheniramine: ∼70% bound to plasma proteins (mainly albumin). Pseudoephedrine: negligible protein binding (<20%).
Approximately 92% bound to albumin.
Chlorpheniramine: Vd ≈ 3–5 L/kg, indicating extensive tissue distribution. Pseudoephedrine: Vd ≈ 2.5–3.5 L/kg, consistent with distribution into total body water. Larger Vd suggests sequestration in tissues like lungs and spleen.
2.4 L/kg; indicates extensive tissue distribution.
Chlorpheniramine: Oral bioavailability ∼25–50% due to first-pass metabolism. Pseudoephedrine: Oral bioavailability ∼100% (>90% absorbed, low first-pass effect). The ER formulation maintains equivalent bioavailability with reduced peak concentrations.
Oral: 60-70% due to first-pass metabolism.
Contraindicated in severe renal impairment (Cr Cl <30 m L/min). No specific dose adjustment for mild to moderate impairment; use with caution.
For GFR 30-50 m L/min: administer every 8 hours. For GFR 10-29 m L/min: administer every 12 hours. For GFR <10 m L/min: use not recommended.
Contraindicated in severe hepatic impairment (Child-Pugh class C). Use with caution in moderate impairment (Child-Pugh class B); no specific dose adjustment defined.
Child-Pugh Class A: no adjustment. Child-Pugh Class B: reduce dose by 50% and extend interval to every 8 hours. Child-Pugh Class C: contraindicated.
Not recommended for children under 12 years. For children 12 years and older, same as adult dosing: 1 tablet every 12 hours.
For children ≥2 years: 0.1-0.2 mg/kg hydrocodone component every 4-6 hours as needed, maximum 6 doses per day. Use weight-based dosing; do not exceed acetaminophen 75 mg/kg/day.
Use with caution due to increased sensitivity to anticholinergic effects (e.g., confusion, urinary retention). Lower initial dose may be considered; avoid use in patients with prostate hypertrophy or glaucoma.
Initiate at lowest effective dose (e.g., 1 capsule every 6 hours) due to increased risk of respiratory depression and falls. Titrate cautiously. Maximum 6 capsules per day.
WARNING: SUICIDALITY AND ANTIDEPRESSANT DRUGS - Antidepressants increased the risk of suicidal thinking and behavior in children, adolescents, and young adults in short-term studies. Monitor closely for clinical worsening and emergence of suicidal thoughts and behaviors.
Addiction, abuse, and misuse; life-threatening respiratory depression; accidental ingestion; neonatal opioid withdrawal syndrome; risks from concomitant use with benzodiazepines or other CNS depressants; and interactions with drugs affecting cytochrome P450 isoenzymes.
Increased risk of suicidal thoughts and behaviors; activation of mania/hypomania; seizures (dose-dependent); increased blood pressure; angle-closure glaucoma; serotonin syndrome; hepatotoxicity; neuropsychiatric reactions; allergic and anaphylactic reactions.
Addiction, abuse, and misuse; life-threatening respiratory depression; accidental ingestion; neonatal opioid withdrawal syndrome; risks from concomitant use with benzodiazepines or other CNS depressants; severe hypotension; gastrointestinal obstruction; seizures; serotonin syndrome; adrenal insufficiency; and androgen deficiency.
Concurrent use with MAOIs; seizure disorder; history of anorexia nervosa or bulimia; abrupt discontinuation of alcohol, benzodiazepines, or anticonvulsants; known hypersensitivity to any component; use of other bupropion-containing products; concomitant use with linezolid or methylene blue.
Significant respiratory depression; acute or severe bronchial asthma in an unmonitored setting or in the absence of resuscitative equipment; known or suspected gastrointestinal obstruction, including paralytic ileus; hypersensitivity to oxycodone, aspirin, or any component of the formulation.
Avoid alcohol and grapefruit juice. Grapefruit juice may inhibit CYP3A4 metabolism of triprolidine, increasing its levels. High-tyramine foods (e.g., aged cheeses, cured meats) may interact with pseudoephedrine, increasing pressor effects. Take with or without food; food may reduce GI irritation but does not affect absorption.
Avoid alcohol and grapefruit juice. Alcohol potentiates CNS depression. Grapefruit juice may increase codeine metabolism via CYP3A4, leading to variable effects. No significant food restrictions otherwise; take with food if GI upset occurs.
TUXARIN ER contains chlorpheniramine and pseudoephedrine. Chlorpheniramine is an antihistamine classified as FDA Pregnancy Category B; animal studies show no risk but no adequate human studies. Pseudoephedrine is FDA Pregnancy Category C; in first trimester, case-control studies suggest a possible association with gastroschisis (odds ratio ~1.8-2.2). After 32 weeks, use may cause premature uterine contractions or fetal tachycardia. Avoid in third trimester due to risk of neonatal irritability and respiratory depression.
No human data; animal studies not available. Avoid during pregnancy, especially first trimester, due to potential oxycodone-induced neural tube defects.
Chlorpheniramine is excreted into breast milk in small amounts (M/P ratio not established). Pseudoephedrine is excreted into breast milk; M/P ratio approximately 3. Initial data indicate pseudoephedrine may reduce milk production by up to 24% with single doses. Use with caution; avoid in cases of established lactation insufficiency. American Academy of Pediatrics considers both drugs compatible with breastfeeding but may cause irritability in infants.
Oxycodone is excreted into breast milk; M/P ratio ~3.6:1. Risk of infant sedation and respiratory depression. Contraindicated during breastfeeding.
No formal dose adjustments established for pregnancy. However, increased plasma volume and renal clearance in pregnancy may reduce pseudoephedrine levels; monitor clinical response. Avoid extended-release formulations if rapid BP fluctuations are a concern. Consider using the lowest effective dose for shortest duration.
No established dose adjustments; increased clearance in pregnancy may require higher doses for analgesia, but use is contraindicated.
TUXARIN ER is a fixed-dose combination of pseudoephedrine (120 mg) and triprolidine (2.5 mg) in an extended-release formulation. The delayed-release component may reduce dosing frequency to every 12 hours. Monitor for CNS stimulation; avoid in severe hypertension or coronary artery disease. Use caution in elderly due to anticholinergic effects (triprolidine).
CODOXY is a fixed-dose combination of codeine (opioid) and doxylamine (antihistamine). Use lowest effective dose for shortest duration due to opioid dependence and respiratory depression risk. Avoid in children <12 years for post-tonsillectomy pain and in those <18 with respiratory compromise. Monitor for CNS depression, especially with alcohol. Doxylamine adds anticholinergic effects (constipation, dry mouth, urinary retention). Caution in elderly, renal impairment, and breastfeeding.
Do not crush or chew the tablet; swallow whole with a full glass of water.,Take every 12 hours; do not exceed 2 tablets in 24 hours.,Avoid driving or operating heavy machinery until you know how this medication affects you.,Notify your doctor if you have high blood pressure, heart disease, glaucoma, or urinary retention.,Do not use with other products containing antihistamines or decongestants.,Stop use and seek medical attention if you experience chest pain, rapid heartbeat, or severe dizziness.
Take exactly as prescribed; do not increase dose or frequency without consulting your doctor.,This medication may cause drowsiness, dizziness, or blurred vision; avoid driving or operating machinery until you know how it affects you.,Avoid alcohol and other sedatives (e.g., benzodiazepines, sleep aids) as they increase risk of severe drowsiness and breathing problems.,Do not use with other products containing codeine or antihistamines (including cough/cold medicines).,Store securely away from children; misuse can cause addiction, overdose, or death.,If you are pregnant, plan to become pregnant, or are breastfeeding, inform your healthcare provider before use.,Common side effects: constipation, dry mouth, nausea. Increase fluid intake and fiber to prevent constipation.,Seek emergency help if you experience slow or shallow breathing, confusion, or fainting.
No interactions on record
No interactions on record
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about TUXARIN ER vs CODOXY, answered by our medical review team.
TUXARIN ER is a Antitussive/decongestant combination that works by TUXARIN ER contains dextromethorphan, an NMDA receptor antagonist and sigma-1 receptor agonist, and bupropion, a norepinephrine and dopamine reuptake inhibitor. The combination is thought to modulate glutamatergic neurotransmission and enhance dopaminergic and noradrenergic signaling.. CODOXY is a Antitussive Combination that works by Oxycodone is a full opioid agonist with relative selectivity for the mu-opioid receptor, although it can bind to other opioid receptors at higher doses. The principal therapeutic action of oxycodone is analgesia. Like all full opioid agonists, there is no ceiling effect for analgesia. Oxycodone is combined with aspirin to provide additive analgesic effects.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between TUXARIN ER and CODOXY 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 TUXARIN ER is: 1 tablet orally every 12 hours; each tablet contains chlorpheniramine maleate 8 mg and phenylephrine HCl 20 mg.. The standard adult dose of CODOXY is: 1-2 capsules orally every 4-6 hours as needed for pain, not to exceed 8 capsules per day. Each capsule contains 5 mg hydrocodone bitartrate and 325 mg acetaminophen.. 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 TUXARIN ER and CODOXY 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. TUXARIN ER is classified as Category C. TUXARIN ER contains chlorpheniramine and pseudoephedrine. Chlorpheniramine is an antihistamine classified as FDA Pregnancy Category B; animal studies show no risk but no adequate h. CODOXY is classified as Category C. No human data; animal studies not available. Avoid during pregnancy, especially first trimester, due to potential oxycodone-induced neural tube defects.. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.