MUCINEX 12HR COLD & FEVER MULTI-SYMPTOM
Clinical safety rating: caution
Comprehensive clinical and safety monograph for MUCINEX 12HR COLD & FEVER MULTI-SYMPTOM (MUCINEX 12HR COLD & FEVER MULTI-SYMPTOM).
Guaifenesin: expectorant - increases respiratory tract fluid output to reduce mucus viscosity. Pseudoephedrine: sympathomimetic - vasoconstrictor via alpha-adrenergic receptors. Acetaminophen: analgesic/antipyretic - inhibits cyclooxygenase (COX) and central prostaglandin synthesis.
| Metabolism | Guaifenesin: metabolized by oxidation and demethylation. Pseudoephedrine: partially hepatic metabolism (N-demethylation). Acetaminophen: hepatic via CYP2E1, CYP1A2, CYP3A4; glucuronidation and sulfation. |
| Excretion | Acetaminophen: renal elimination of metabolites (glucuronide 45-55%, sulfate 20-30%, cysteine/mercapturate 15-20%) and 2-5% unchanged; Dextromethorphan: renal (<1% unchanged, primarily metabolites); Guaifenesin: renal (metabolites, ~0.6% unchanged); Phenylephrine: renal (primarily metabolites, 2-5% unchanged). |
| Half-life | Acetaminophen: 2-3 hours (prolonged in hepatic impairment, up to 6-8 hours in overdose); Dextromethorphan: 3-6 hours (CYP2D6 poor metabolizers: 15-40 hours); Guaifenesin: 1-2 hours; Phenylephrine: 2-3 hours (oral). |
| Protein binding | Acetaminophen: 10-25% (albumin); Dextromethorphan: ~60% (albumin); Guaifenesin: <10%; Phenylephrine: ~95% (albumin). |
| Volume of Distribution | Acetaminophen: 0.9-1.0 L/kg; Dextromethorphan: 5-9 L/kg; Guaifenesin: 1-2 L/kg; Phenylephrine: 2-5 L/kg. |
| Bioavailability | Acetaminophen: 85-98% (oral); Dextromethorphan: 11-66% (oral, first-pass metabolism; CYP2D6 poor metabolizers: up to 80%); Guaifenesin: ~90% (oral); Phenylephrine: 38-50% (oral, extensive first-pass metabolism by MAO). |
| Onset of Action | Acetaminophen: 30-60 min (oral); Dextromethorphan: 15-30 min (oral); Guaifenesin: 30-60 min (oral); Phenylephrine: 15-30 min (oral). |
| Duration of Action | Acetaminophen: 4-6 hours (analgesic/antipyretic); Dextromethorphan: 4-6 hours; Guaifenesin: 4-6 hours; Phenylephrine: 4-6 hours (oral). Dosing interval: every 12 hours. |
2 tablets (each containing: acetaminophen 650 mg, guaifenesin 600 mg, phenylephrine HCl 10 mg) orally every 12 hours; maximum 4 tablets per 24 hours. Avoid exceeding 4 doses (8 tablets) of acetaminophen per day.
| Dosage form | TABLET, EXTENDED RELEASE |
| Renal impairment | Not recommended if CrCl <30 mL/min. For CrCl 30-50 mL/min, extend dosing interval to every 12-24 hours based on response and tolerability. Avoid if severe renal impairment. |
| Liver impairment | Contraindicated in severe hepatic impairment (Child-Pugh class C). Caution in moderate impairment (Child-Pugh B): reduce dose by 50% or extend interval; limit acetaminophen to <2000 mg/day. Mild impairment (Child-Pugh A): no adjustment necessary. |
| Pediatric use | Not recommended for children under 12 years. For ages 12 and older, use adult dose. Weight-based: not established; alternative products with weight-based dosing should be used for those under 13 years. |
| Geriatric use | Caution due to increased sensitivity to anticholinergic effects of phenylephrine (e.g., hypertension, urinary retention). Start with lower doses: 1 tablet every 12 hours. Monitor for adverse effects, especially cardiovascular and renal. Consider avoiding phenylephrine in elderly with hypertension or prostate disorders. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for MUCINEX 12HR COLD & FEVER MULTI-SYMPTOM (MUCINEX 12HR COLD & FEVER MULTI-SYMPTOM).
| Breastfeeding | Guaifenesin: Excreted in milk in small amounts, no reported adverse effects in infants. Acetaminophen: M/P ratio ~1.0, low risk at recommended doses. Phenylephrine: Poor oral bioavailability, minimal excretion in milk. Generally compatible with breastfeeding; monitor infant for irritability or sedation. |
| Teratogenic Risk | FDA Pregnancy Category C. First trimester: Guaifenesin crosses placenta, limited data show possible small increased risk of neural tube defects; acetaminophen and phenylephrine generally considered low risk at recommended doses. Second and third trimesters: Acetaminophen safe in standard doses; phenylephrine may reduce uterine blood flow; guaifenesin lacks adequate studies. Avoid prolonged high-dose acetaminophen due to potential maternal hepatotoxicity. |
■ FDA Black Box Warning
No FDA boxed warning.
| Serious Effects |
Hypersensitivity to any component. Concomitant use with MAOIs or within 14 days of MAOI use. Severe hypertension or coronary artery disease (pseudoephedrine).
| Precautions | Do not exceed recommended dose; avoid use with other acetaminophen-containing products due to risk of hepatotoxicity. Caution in hypertension, cardiovascular disease, diabetes, hyperthyroidism, closed-angle glaucoma, prostatic hypertrophy. Avoid in severe hepatic impairment. May cause dizziness or drowsiness. |
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| Fetal Monitoring | Monitor maternal blood pressure (due to phenylephrine) and liver function tests if prolonged high-dose acetaminophen. Assess fetal growth if used chronically. Watch for signs of premature labor if high-dose guaifenesin used. |
| Fertility Effects | No known significant effects on fertility. Animal studies for guaifenesin and phenylephrine show no impairment. Acetaminophen at high doses may affect ovulation (prostaglandin inhibition). |