Although its mechanism of action has yet to be completely elucidated; secretolytic and secretomotor effects have been found in various investigations, however. On average, action following oral administration commences after 30 minutes and persists for 6-12 hours depending on the extent of the single dose.

In preclinical investigations, it increases the proportion of serous bronchial secretion. The transport of mucus is thought to be promoted by the reduction of viscosity and the activation of the ciliated epithelium. Ambroxol induces activation of the surfactant system by acting directly on the type II pneumocytes of the alveoles and the Clara cells in the region of the small airways. It promotes the formation and outward transfer of surface-active material in the alveolar and bronchial region of lungs. These effects have been demonstrated in cell cultures and in vivo on various species.

Acetylcysteine undergose rapid deacetylation in vivo to yield cysteine or oxidation to yield diacetylcystine. Acetylcysteine is a potent mucolytic agent. The mucolytic action of Acetylcysteine is probably due to the opening of disulfide bonds in the mucus mucoproteins by Acetylcysteine’s sulfydryl group. Acetylcysteine acts as surfactant to expel mucus. Exerts synergistic action due to Ambroxol & Acetylcysteine. Acetylcysteine also control cellular damage in pulmonary diseases.

During acute exacerbations of bronchitis it should be given with the appropriate antibiotic. Respiratory- tract disorders associated with increased or viscous mucus. Reducing mucus and helping with breathing in various lung conditions like cystic fibrosis.

Elevated serum transaminase levels were temporally associated with acetylcysteine (the active ingredient contained in NAC) administration in a patient with cystic fibrosis.

Patient should not take acetylcysteine at the same time as antibiotics. Antibiotics can however be taken at least two hours after acetylcysteine.

Dosage adjustment is necessary in patients with moderate or severe renal impairment. There have been very few reports of severe skin lesion such as Stevens-Johnson Syndrome and toxic epidermal necrolysis (TEN)in temporal association with the administration of expectorants such as ambroxil hydrochloride. Do not use before bedtime.

Concomitant use with antitussive agents, e.g. codeine should be avoided, because they may inhibit cough reflex. Nitroglycerin interacts with acaetylcysteine. Nitroglycerine can dilate blood vessels and increase blood flow. Taking acetylcysteine seems to increase the effects including headache, dizziness, and light headednesss.

Activated charcoal interacts with acetylcysteine. Activated charcoal sometimes used to prevent poisoning in people who take too much acetaminophen and other medications. Activated charcoal can bind up these medications in the stomach and prevent them from being absorbed by the body.

In analogy to preclinical examinations, increased salivation, retching, vomiting and a drop in blood pressure may occur following extreme overdose. Acute measures such as instituting vomiting and gastric lavage are not generally indicated and are only to be considered following extreme overdose. A symptomatic therapy is recommended.

Brief restlessness and diarrhoea have been reported. Ambroxol has been tolerated well on oral administration up to a dosage of 25mg/kg/day.