Erdosteine Add-on Therapy in Mucus-Predominant COPD With Recurrent Symptoms: A 6-Month Case Report
Dr. Amit P Gawande *
Correspondence to: Dr. Amit P Gawande, Consultant Chest Physician, Critical Care Specialist, Mumbai.
Copyright
© 2026 Dr. Amit P Gawande. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Received: 03 June 2026
Published: 01 July 2026
DOI: https://doi.org/10.5281/zenodo.21065683
Introduction
COPD with chronic cough and sputum production remains a clinically important phenotype because mucus hypersecretion is associated with worse symptoms, impaired quality of life, and higher exacerbation burden. Among mucoactive agents, erdosteine has been studied as add-on treatment in chronic bronchitis and COPD because it can reduce mucus viscosity, facilitate expectoration, and exert antioxidant effects. A meta-analysis of 10 studies involving 1,278 patients found that erdosteine improved clinical scores, reduced the overall risk of chronic bronchitis/COPD exacerbations, reduced the risk of at least one exacerbation, prolonged time to first exacerbation, and lowered hospitalization risk. In the RESTORE trial, add-on erdosteine reduced the mean exacerbation rate by 47%, reduced mild exacerbations, shortened exacerbation duration, and increased exacerbation-free time in patients with moderate COPD and a history of exacerbations.
This report presents a clinically relevant outpatient case in which erdosteine appeared to play a crucial role in improving mucus-related symptoms and maintaining exacerbation-free stability over 6 months.
Patient Information
A 59-year-old man with previously diagnosed COPD presented with recurrent respiratory symptoms characterized predominantly by chronic cough and troublesome mucus production. Over the pre-enrollment period, he experienced recurrent symptomatic episodes suggestive of unstable chronic bronchitis disease, with 2 exacerbations last year for which he was hospitalized for one of them.
The patient has a history of smoking with a 10-pack year history. He was an office clerk and no other occupational exposure but he had had a history of allergies. He has 2 exacerbations a year with at least one hospitalization. His symptoms consist of recurrent cough with expectoration and dyspnea on exertion since 1 month. He was on regular therapy of formoterol and budesonide and did pulmonary rehabilitation but inconsistently. He was also a known case of hypertension.
Clinical Findings and Assessment
At baseline, the dominant clinical problem was persistent mucus production with recurrent symptoms despite standard COPD care. Baseline spirometry showed an FEV1 of 58% predicted with post BD predicted at 61%, consistent with airflow limitation in a patient already labeled as COPD. His FEV1/FVC ratio is 50%. On 6min min walk test he covered a distance of 500mts with change in spo2 was 4%. He had mMRC dyspnea grade 3, BMI was 27 and CAT score of 15. His baseline oxygen was 94%. His CBC showed an absolute eosinophil count of 580.
Therapeutic Intervention
The patient was started on tablet/capsule erdosteine 300 mg twice daily as add-on therapy together with triple inhalation therapy and structured pulmonary rehabilitation. A 300 mg twice-daily adult dose is consistent with standard product information for erdosteine. Triple inhaled therapy and pulmonary rehabilitation remained part of the background disease-modifying strategy throughout follow-up, which reflects current multidimensional COPD care emphasizing inhaled maintenance treatment, technique review, and rehabilitation where appropriate.
Follow-up and Outcomes
The patient was followed for 6 months after initiation of erdosteine. During this period, he reported marked improvement in daily respiratory symptoms, with only minimal residual symptoms by the end of follow-up, and he experienced no COPD exacerbation. Spirometry improved from an FEV1 of 58% predicted at baseline to 66% predicted after 6 months. His mMRC grade came to 2 and CAT score to 11. His symptoms improved and his mucus clearance improved.
Discussion
In this case, add-on erdosteine was associated with a clear clinical improvement in the patient’s mucus-predominant COPD symptoms, with reduction in cough, sputum burden, and day-to-day respiratory discomfort over the 6-month follow-up period. The most striking benefit was the absence of exacerbations during observation, suggesting that erdosteine may have helped stabilize the patient’s disease course beyond routine inhaled therapy and pulmonary rehabilitation alone. By improving mucus clearance and reducing airway irritation, erdosteine likely addressed a key treatable trait in this patient, which translated into fewer symptom flares, better functional status, and a more predictable daily routine. As symptoms became minimal and exacerbation-free follow-up was maintained, the patient’s overall quality of life also improved, particularly in terms of comfort, activity tolerance, and reduced treatment-related anxiety.
Conclusion
This case suggests that erdosteine can be a valuable add-on therapy in selected COPD patients with recurrent mucus production and symptom burden. In this patient, its use was associated with marked symptom relief, no exacerbations over 6 months, and an improved quality of life, supporting its role as an effective mucoactive agent in COPD management.