MUCINEX D

Clinical safety rating: caution

Comprehensive clinical and safety monograph for MUCINEX D (MUCINEX D).

How it works

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.

What the body does with it

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)

Classification & Brands

Dosing & administration

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.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for MUCINEX D (MUCINEX D).

Breastfeeding	Guaifenesin: Excreted into breast milk in small amounts; considered compatible with breastfeeding. Pseudoephedrine: Concentrated in breast milk (M/P ratio approximately 3.5); may cause irritability and decreased milk production. Use with caution; monitor infant for agitation and feeding difficulties.
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.

Warnings & precautions

■ FDA Black Box Warning

None

Side Effect Profile

Serious Effects

Absolute Contraindications

Hypersensitivity to any ingredient, severe hypertension, severe coronary artery disease, narrow-angle glaucoma, urinary retention, concurrent MAOI therapy or within 14 days of stopping an MAOI.

Clinical Precautions

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.

Clinical Tips & Counseling

Drug interactions

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MUCINEX D

Clinical safety rating: caution

Comprehensive clinical and safety monograph for MUCINEX D (MUCINEX D).

How it works

What the body does with it

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)

Classification & Brands

Dosing & administration

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.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for MUCINEX D (MUCINEX D).

Breastfeeding	Guaifenesin: Excreted into breast milk in small amounts; considered compatible with breastfeeding. Pseudoephedrine: Concentrated in breast milk (M/P ratio approximately 3.5); may cause irritability and decreased milk production. Use with caution; monitor infant for agitation and feeding difficulties.
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.

Warnings & precautions

■ FDA Black Box Warning

None

Side Effect Profile

Serious Effects

Absolute Contraindications

Hypersensitivity to any ingredient, severe hypertension, severe coronary artery disease, narrow-angle glaucoma, urinary retention, concurrent MAOI therapy or within 14 days of stopping an MAOI.