Mucinex - Drug Monograph

Introduction

Mucinex is a widely used over-the-counter expectorant medication containing guaifenesin as its active ingredient. It is primarily indicated for symptomatic relief of respiratory conditions characterized by thick, tenacious mucus. First approved by the FDA in 2002, Mucinex has become a mainstay in the management of chest congestion associated with various respiratory tract conditions.

Mechanism of Action

Guaifenesin, the active component of Mucinex, works as an expectorant by increasing the volume and reducing the viscosity of respiratory tract secretions. It acts on the gastric mucosa to produce vagally-mediated stimulation of respiratory secretions, thereby enhancing the output of lower respiratory tract fluid. This action facilitates the removal of mucus from the airways through improved ciliary clearance and more productive coughing.

Indications

• Temporary relief of chest congestion due to common cold, bronchitis, and other respiratory infections
• Symptomatic management of mucus in the respiratory tract
• Adjunctive therapy in conditions where thick mucus impedes respiratory function

Dosage and Administration

• Immediate-release: 200-400 mg every 4 hours
• Extended-release: 600-1200 mg every 12 hours
• Maximum daily dose: 2400 mg

• 100-200 mg every 4 hours
• Maximum daily dose: 1200 mg

• Renal impairment: Use with caution; consider reduced dosing
• Hepatic impairment: No specific dosage adjustment recommended
• Elderly: No dosage adjustment typically required
• Pregnancy: Category C - use only if potential benefit justifies potential risk

Pharmacokinetics

Contraindications

• Hypersensitivity to guaifenesin or any product components
• Patients with known hypersensitivity reactions to related compounds
• Use in children under 6 years of age (unless specifically directed by healthcare provider)

Warnings and Precautions

• Use with caution in patients with chronic cough or cough accompanied by excessive secretions
• Not recommended for prolonged use (>7 days) without medical supervision
• Caution in patients with renal impairment due to potential metabolite accumulation
• Patients with phenylketonuria should avoid formulations containing aspartame
• May cause drowsiness or dizziness in some patients

Drug Interactions

• Minimal clinically significant drug interactions reported
• Theoretical potential to enhance effects of other CNS depressants
• No known interactions with cytochrome P450 enzyme system
• May potentially affect absorption of other medications if taken simultaneously

Adverse Effects

• Nausea
• Vomiting
• Gastrointestinal discomfort
• Dizziness
• Headache

• Drowsiness
• Rash
• Diarrhea

• Anaphylactic reactions (very rare)
• Severe dermatological reactions

Monitoring Parameters

• Respiratory symptom improvement
• Sputum characteristics and volume
• Cough frequency and productivity
• Adverse effect profile
• Hydration status (especially in elderly patients)

Patient Education

• Take with a full glass of water to enhance expectorant effect
• Maintain adequate hydration to help loosen mucus
• Do not crush or chew extended-release tablets
• Do not use for more than 7 days without medical advice
• Seek medical attention if symptoms worsen or persist beyond 7 days
• Be aware that product may cause drowsiness; use caution when operating machinery
• Store at room temperature away from moisture and heat

References

1. FDA Drug Approval Package: Mucinex (guaifenesin) NDA #21-282 2. AHFS Drug Information®: Guaifenesin Monograph 3. Micromedex® Healthcare Series: Guaifenesin 4. Rowe RC, et al. Handbook of Pharmaceutical Excipients. 7th ed. London: Pharmaceutical Press; 2012 5. MedlinePlus: Guaifenesin. U.S. National Library of Medicine 6. Product labeling: Mucinex® (guaifenesin) extended-release tablets 7. Ziment I. Respiratory Pharmacology and Therapeutics. Philadelphia: WB Saunders; 1988 8. American Pharmacists Association. Handbook of Nonprescription Drugs. 19th ed. Washington, DC: APHA; 2017