Introduction
Mucolytics are medicines that reduce the thickness and stickiness of sputum (thick mucus) in the respiratory tract. By breaking down mucus bonds, these drugs make the secretions thinner and easier to cough out. They are especially useful in conditions where mucus becomes thick, tenacious or forms plugs.
Common mucolytics: Acetylcysteine, Bromhexine, Ambroxol, Carbocisteine.
Acetylcysteine
Acetylcysteine is a derivative of the amino acid cysteine. It reduces mucus viscosity by breaking the disulphide bonds present in mucoproteins. This results in thinning of mucus and easier expectoration.
Additional Important Action
Acetylcysteine is also used as an antidote in paracetamol (acetaminophen) poisoning. In toxic doses, paracetamol depletes liver glutathione and forms harmful metabolites. Acetylcysteine provides an alternate binding substrate, helping protect the liver and prevent serious toxicity.
Dosage Form and Administration
It can be given as an aerosol spray or instilled directly into the respiratory tract.
Preparations
- MUCOTAB 600 mg tablet
- FLUIMUCIL 200 mg, 600 mg effervescent tablets
- MUCOMIX 200 mg/ml injection (1, 2, 5 ml ampoules)
Adverse Reactions
- Bronchospasm
- Fever
- Nausea and vomiting
- Possible irritation of gastric mucosal barrier when taken orally
Bromhexine
Bromhexine is derived from the plant alkaloid vasicine (from the Vasaka plant). It reduces sputum viscosity by depolymerizing mucopolysaccharides and releasing lysosomal enzymes.
Adverse Reactions
- Rhinorrhoea (watery nasal discharge)
- Lacrimation (watery eyes)
- Gastric irritation
- Allergic reactions
Preparations
- Bromhexine 8 mg tablet
- 4 mg/5 ml elixir
Ambroxol
Ambroxol is an active metabolite of bromhexine. It has similar mucolytic properties but often offers better tolerance and improved effectiveness.
Dosage
Adult dose: 15–30 mg, three times daily.
Preparations
- AMBRIL, AMBROLITE, AMBRODIL, MUCOLITE 30 mg tablets
- 30 mg/5 ml liquid
- 7.5 mg/ml drops
- ACOCONTIN 75 mg controlled-release tablets
Uses and Adverse Effects
Similar to bromhexine; well tolerated and widely used in both adults and children.
Carbocisteine
Carbocisteine liquefies thick mucus in a similar way to acetylcysteine. It is taken orally and has shown good response in chronic bronchitis and respiratory conditions with thick secretions.
Dose
250–750 mg three times daily.
Adverse Reactions
- Gastric discomfort
- Skin rashes
Important Contraindication
It may disrupt the gastric mucus barrier, so it should be avoided in patients with peptic ulcer.
Preparations
- MUCODYNE 375 mg capsules; 250 mg/5 ml syrup
- Combination formulations with antibiotics such as amoxicillin and cephalexin:
- CARBOMOX (Carbocisteine + Amoxicillin)
- CARBICEF (Carbocisteine + Cephalexin)
Uses of Mucolytics
Mucolytics are especially helpful in conditions where mucus becomes very thick or sticky:
- Asthmatic bronchitis
- Chronic bronchitis
- Bronchiectasis
- Cystic fibrosis
- Tracheostomy patients (to avoid mucus plugs)
Detailed Notes:
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