Ambroxol for Dry Cough: Mechanism, Dosing & Evidence

Ambroxol is a mucoactive agent (mucolytic + secretolytic) widely used for productive and dry cough associated with viscous mucus.

Mechanisms of Action

• Stimulates surfactant synthesis (type II pneumocytes) → reduces mucus viscosity & surface tension.
• Increases ciliary beat frequency → enhances mucociliary clearance.
• Antioxidant & anti‑inflammatory: Inhibits ROS, NF‑κB, cytokine release.
• Local anesthetic effect: Blocks Na⁺ channels → reduces cough reflex sensitivity.

Dosing (Adults)

• Tablet/syrup: 30 mg TID (range 15–30 mg TID).
• Extended‑release: 75 mg once daily.
• Duration: Typically 5–14 days; not for chronic use without review.

Evidence Summary

• Cochrane reviews: Modest benefit in acute bronchitis (reduces cough frequency/severity at day 7).
• Superior to placebo for mucus viscosity reduction.
• Well tolerated; GI upset most common AE.

Precautions

• Rare hypersensitivity (rash, angioedema).
• Use cautiously in gastric ulcer (may increase gastric mucus but theoretical).
• Pregnancy: Category B (animal data only); avoid 1st trimester unless benefit > risk.
• Pediatric: Dosed by weight; syrup available.

When to Re‑Evaluate

Cough >3 weeks, hemoptysis, weight loss, fever, dyspnea → investigate (CXR, spirometry, etc.).