Mucolytic agent
ATC code: R05CB03 (Carbocisteine)
An L-cysteine amino acid derivative. Activates sialyltransferase in bronchial goblet cells and normalizes the ratio of acidic to neutral sialomucins in secretions, reducing sputum viscosity. Unlike acetylcysteine, it does not break mucopolysaccharide disulfide bonds. Half-life 2 hours, dosed 2–3 times daily. Widely used in Spain under the Pectox brand.
Adjunct
Used in cough with hard-to-clear sputum in acute bronchitis, chronic obstructive lung disease, and bronchiectasis. Adult dose 750 mg three times daily. In COPD, long-term use (over 6 months) modestly reduces exacerbation frequency per the Cochrane 2019 meta-analysis (RR 0.75, 95% CI 0.68–0.84). In acute bronchitis in otherwise healthy adults, effect is modest – not a preferred choice in international guidelines.
Sources
The drug is promoted for these uses outside international guidelines. Each entry below is analyzed against AEMPS, FDA, EMA, Cochrane and major RCTs.
Not recommended
Carbocisteine is a mucolytic. It is prescribed for chronic respiratory diseases with thick sputum. For acute viral infections in children, carbocisteine is prescribed at the first signs of a cold and to enhance the immune response. The Cochrane review by Chalumeau 2013 and the PRAC restricted carbocisteine use in children under 2 due to risk of paradoxical worsening of breathing. The drug carries specific risks: allergic reactions and GI disturbances. If carbocisteine was prescribed to a child for an ordinary cold, consider seeking a second opinion.
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Contraindicated in T1. T2 and T3 use is acceptable when indicated.
Limited data. Use with caution during lactation.
Reference information, not a clinical decision. Discuss feeding pauses or changes with your physician or an IBCLC.
Carbocisteine is evaluated for the following indications with varying evidence strength: Productive cough (evidence tier C), Immune support and respiratory infection care (evidence tier F). See the full indication matrix with dosing and citations above on this page.
Common side effects of Carbocisteine (≥ 1 in 100): Nausea, vomiting, Diarrhea, Epigastric pain, Headache, Skin rash. See the Safety section for uncommon and serious reactions.
FDA category C. Contraindicated in T1. T2 and T3 use is acceptable when indicated.
Limited data. Use with caution during lactation.
Carbocisteine is contraindicated in: Carbocisteine hypersensitivity; Active peptic ulcer; Age under 2; Severe hepatic or renal impairment; T1 of pregnancy. Full list in the Safety section.