MUCINEX D
Clinical safety rating
cautionComprehensive clinical and safety monograph for MUCINEX D (MUCINEX D).
Mucinex D contains guaifenesin, which is an expectorant that increases respiratory tract fluid secretions to reduce mucus viscosity and enhance mucus clearance, and pseudoephedrine, a sympathomimetic amine that acts as a decongestant via alpha-adrenergic receptor agonism in the nasal mucosa, causing vasoconstriction and reducing nasal congestion.
| Metabolism | Guaifenesin is metabolized primarily by oxidation to beta-(2-methoxyphenoxy)lactic acid. Pseudoephedrine is partially hepatic via N-demethylation to norpseudoephedrine. Both are excreted renally. |
| Excretion | Guaifenesin: Renal (primarily as metabolites, <5% unchanged). Pseudoephedrine: Renal (70-90% unchanged, dependent on urine pH) |
| Half-life | Guaifenesin: 1 hour (short t½, requires frequent dosing). Pseudoephedrine: 5-8 hours (prolonged with alkaline urine) |
| Protein binding | Guaifenesin: <10% (minimal binding). Pseudoephedrine: <5% (negligible binding to plasma proteins) |
| Volume of Distribution | Guaifenesin: ~1.0 L/kg (distributes into total body water). Pseudoephedrine: ~2.6 L/kg (extensive tissue distribution) |
| Bioavailability | Guaifenesin: ~95% (oral, well absorbed). Pseudoephedrine: ~100% (oral, complete absorption) |
| Onset of Action | Oral: Guaifenesin ~30 minutes; Pseudoephedrine ~30 minutes |
| Duration of Action | Guaifenesin: 4-6 hours. Pseudoephedrine: 4-6 hours (extended-release formulations up to 12 hours) |
| Molecular Weight | Pseudophedrine HCl: 201.69 Da; Guaifenesin: 198.22 Da; combination product = 399.91 Da (sum of free bases). |
Mucinex D contains guaifenesin 600 mg and pseudoephedrine 60 mg per extended-release tablet. Usual adult dose: 1 tablet orally every 12 hours, not to exceed 2 tablets in 24 hours.
| Dosage form | TABLET, EXTENDED RELEASE |
| Renal impairment | For pseudoephedrine: CrCl 30-59 mL/min: administer every 24 hours; CrCl <30 mL/min: not recommended. Guaifenesin: no specific adjustment but caution in severe renal impairment. |
| Liver impairment | Child-Pugh Class A or B: no adjustment needed. Child-Pugh Class C: insufficient data; use with caution due to potential accumulation of pseudoephedrine. |
| Pediatric use | Not recommended for children under 12 years. For children 12 years and older: same as adult dosing (1 tablet every 12 hours). |
| Geriatric use | Start at lower end of dosing; consider CrCl <30 mL/min: avoid use. Monitor for hypertension and CNS effects due to pseudoephedrine. |
| 1st trimester | Avoid. Pseudophedrine may cause vasoconstriction and reduce uterine blood flow; guaifenesin safety not established in first trimester. Use only if benefit outweighs risk. |
| 2nd trimester | Caution. Pseudophedrine may cause fetal tachycardia; guaifenesin generally safe but data limited. Use lowest effective dose for shortest duration. |
| 3rd trimester | Avoid near term. Pseudophedrine may induce uterine contractions and cause neonatal irritability; guaifenesin may increase risk of bleeding if used near delivery. |
Clinical note
Comprehensive clinical and safety monograph for MUCINEX D (MUCINEX D).
| Placental transfer | Pseudophedrine crosses placenta via passive diffusion; guaifenesin also crosses but to a lesser extent. Fetal exposure is confirmed. |
| Breastfeeding | Pseudophedrine is excreted into breast milk and may cause irritability and disturbed sleep in nursing infants; it may also reduce milk production. Guaifenesin is likely safe but limited data. Avoid or use lowest dose for shortest duration. |
| Lactation Rating | L3 (Moderately Safe) - Pseudophedrine; Guaifenesin: L1 (Safe) but combination product rated based on pseudoephedrine. |
| Teratogenic Risk | Mucinex D contains guaifenesin and pseudoephedrine. Guaifenesin: Limited human data; animal studies show no teratogenicity at therapeutic doses. Pseudoephedrine: Possible association with gastroschisis in first trimester; avoid use during first trimester. Second and third trimester: Use only if benefit outweighs risk; may cause uterine vasoconstriction and reduced placental perfusion. |
| Fetal Monitoring | Monitor maternal blood pressure and heart rate due to pseudoephedrine; assess fetal heart rate and uterine activity if used near term. Watch for signs of reduced placental perfusion (e.g., decreased fetal movements). |
| Fertility Effects | No known significant effects on fertility with standard doses. Pseudoephedrine may cause reversible sperm motility reduction in males. |
■ FDA Black Box Warning
None
| Serious Effects |
Hypersensitivity to pseudoephedrine or guaifenesinSevere hypertensionCoronary artery diseaseUse within 14 days of MAOI therapyNarrow-angle glaucomaUrinary retentionPheochromocytomaConcurrent use of other sympathomimetics
| Precautions | Use with caution in patients with hypertension, cardiovascular disease, hyperthyroidism, diabetes, prostatic hypertrophy, or glaucoma. Avoid in patients with severe hepatic or renal impairment. May cause dizziness, nervousness, or insomnia. Do not exceed recommended dose. Do not use with other sympathomimetics. Contraindicated with MAOIs or within 14 days of stopping them. |
| Food/Dietary | Avoid caffeine (coffee, tea, cola, chocolate) as it may increase CNS stimulation. High-tyramine foods (aged cheese, cured meats, soy sauce) are generally not contraindicated with pseudoephedrine alone, but caution if patient is also taking MAOIs (contraindicated). Alcohol may worsen certain side effects or increase risk of dizziness; limit or avoid. |
| Clinical Pearls | Mucinex D combines guaifenesin (expectorant) and pseudoephedrine (decongestant). Avoid in patients with hypertension, severe coronary artery disease, or MAOI use within 14 days. Monitor for CNS stimulation and insomnia. Use caution in BPH, glaucoma, and hyperthyroidism. Maximum pseudoephedrine dose is 240 mg/day immediate-release or 240 mg/day extended-release. Guaifenesin maximal dose is 2.4 g/day. Do not crush or chew extended-release tablets. |
| Patient Advice | Do not take within 14 days of MAO inhibitors. · Avoid taking with other cold medications containing decongestants or cough suppressants. · Take exactly as directed; do not exceed recommended dose. · Drink plenty of fluids to help loosen mucus. · Do not crush or chew extended-release tablets; swallow whole. · Discontinue and consult doctor if you experience rapid pulse, dizziness, or nervousness. · May cause difficulty sleeping; take last dose early evening. · Not for use in children under 12 unless directed by doctor. · Do not use for longer than 7 days. |
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