Acetylcysteine is a versatile active ingredient used primarily for its mucolytic properties.^1,2 

Initially developed as a treatment for acetaminophen overdose, acetylcysteine has found applications in respiratory conditions, particularly in managing symptoms associated with cough, cold, and sinusitis.^2,3 

PHARMACODYNAMICS OF ACETYLCYSTEINE 

Acetylcysteine works by breaking down disulfide bonds in mucoproteins, which are a component of mucus. This action reduces the viscosity of mucus, making it easier to expectorate. By enhancing mucus clearance, acetylcysteine improves airway function and alleviates congestion, a common symptom in respiratory infections.⁴ 

 Additionally, acetylcysteine acts as an antioxidant. It replenishes intracellular levels of glutathione, a critical antioxidant that protects cells from oxidative damage. This property is particularly beneficial in respiratory conditions where oxidative stress can exacerbate inflammation and tissue damage.³ 

THERAPEUTIC BENEFITS IN COUGH 

Coughing is a reflex that helps clear the airways of mucus and irritants.5 In conditions like chronic bronchitis or acute respiratory infections, excessive mucus production can lead to persistent and productive coughs.6 Acetylcysteine’s mucolytic action aids in liquefying thick mucus, facilitating its removal through coughing and improving respiratory function.⁴ 

Clinical studies have shown that acetylcysteine can reduce the frequency and severity of cough in patients with chronic obstructive pulmonary disease (COPD) and bronchitis. Its ability to modulate mucus production and enhance clearance makes it an effective adjunct therapy in managing chronic coughs associated with these conditions.^1,7 

ROLE IN COLD AND SINUSITIS 

The common cold, often caused by viral infections, leads to symptoms such as nasal congestion, runny nose, and cough.8 Sinusitis, the inflammation of the sinuses, can result from viral, bacterial, or fungal infections and often presents with similar symptoms, including facial pain and pressure.⁹ 

In these conditions, acetylcysteine's mucolytic properties help reduce nasal and sinus congestion by breaking down thick mucus, facilitating its drainage.1,2,9 This not only relieves congestion but also helps prevent secondary bacterial infections by promoting the clearance of mucus that can serve as a breeding ground for pathogens.⁹ 

Furthermore, acetylcysteine's antioxidant properties can mitigate the inflammatory response associated with viral infections,¹⁰ potentially reducing the duration and severity of cold and sinusitis symptoms. 

CLINICAL APPLICATIONS AND DOSAGE 

Acetylcysteine is available in various forms, including oral tablets, effervescent granules, and inhalation solutions. The appropriate form and dosage depend on the specific condition being treated and the patient's overall health status.^1,10 

SAFETY AND SIDE EFFECTS 

Acetylcysteine is generally well-tolerated, with a favourable safety profile. Common side effects include gastrointestinal disturbances such as nausea, vomiting, and diarrhoea. Rarely, allergic reactions and bronchospasm may occur, particularly in individuals with asthma.^1,2,3 

With its dual action as a mucolytic and antioxidant makes it effective in reducing mucus viscosity, improving clearance, and mitigating inflammation, acetylcysteine is a valuable agent in the management of cough, cold, and sinusitis. 

REFERENCES 

1. Raghu G, Berk M, Campochiaro PA, Jaeschke H, Marenzi G, Richeldi L, Wen FQ, Nicoletti F, Calverley PMA. The Multifaceted Therapeutic Role of N-Acetylcysteine (NAC) in Disorders Characterized by Oxidative Stress. Curr Neuropharmacol. 2021;19(8):1202-1224. doi: 10.2174/1570159X19666201230144109. PMID: 33380301; PMCID: PMC8719286. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8719286/ 
2. Tieu S, Charchoglyan A, Paulsen L, Wagter-Lesperance LC, Shandilya UK, Bridle BW, Mallard BA, Karrow NA. N-Acetylcysteine and Its Immunomodulatory Properties in Humans and Domesticated Animals. Antioxidants. 2023; 12(10):1867. Available from:  https://doi.org/10.3390/antiox12101867 
3. Schwaiger T. A Review of the Use of N-Acetyl-Cysteine (NAC) in Clinical Practice. Natural Medicine Journal. 6 October 2021. Available from: https://www.naturalmedicinejournal.com/journal/review-use-n-acetyl-cysteine-nac-clinical-practice 
4. Sadowska AM. N-Acetylcysteine mucolysis in the management of chronic obstructive pulmonary disease. Therapeutic Advances in Respiratory Disease. 2012;6(3):127-135. doi:10.1177/1753465812437563. Available from: https://journals.sagepub.com/doi/full/10.1177/1753465812437563 
5. Bakhtiar A, Juwita PM. Management of Cough. Jurnal Respirasi. 2020. p-ISSN: 2407-0831; e-ISSN: 2621-8372. DOI: 10.20473/jr.v7-I.2.2021.93-99. Available from: https://download.garuda.kemdikbud.go.id/article.php?article=2280769&val=15433&title=Management%20of%20Cough 
6. Matthew J. Martin, Tim W. Harrison. Causes of chronic productive cough: An approach to management. Respiratory Medicine. 2015;109(9):1105-1113. ISSN 0954-6111. Available from: https://doi.org/10.1016/j.rmed.2015.05.020. 
7. Calverley, P., Rogliani, P. & Papi, A. Safety of N-Acetylcysteine at High Doses in Chronic Respiratory Diseases: A Review. Drug Saf 2021;44:273–290. Available from: https://doi.org/10.1007/s40264-020-01026-y 
8. Pappas DE. The Common Cold. Principles and Practice of Pediatric Infectious Diseases. 2018:199–202.e1. doi: 10.1016/B978-0-323-40181-4.00026-8. Epub 2017 Jul 18. PMCID: PMC7152197. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7152197/ 
9. Leung AK, Hon KL, Chu WC. Acute bacterial sinusitis in children: an updated review. Drugs Context. 2020 Nov 23;9:2020-9-3. doi: 10.7573/dic.2020-9-3. PMID: 33281908; PMCID: PMC7685231. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7685231/ 
10. Tenório MCdS, Graciliano NG, Moura FA, Oliveira ACMd, Goulart MOF. N-Acetylcysteine (NAC): Impacts on Human Health. Antioxidants. 2021; 10(6):967. Available from: https://doi.org/10.3390/antiox10060967