Each effervescent tablet contains: Acetylcysteine USP 600 mg, Excipients q.s.
Pharmacology: Acetylcysteine reduces the viscosity of mucus and other secretions, in vitro. It is thought to act by reducing disulfide bonds in proteins and altering their configuration to improve flow characteristics. It is readily converted to cysteine in vivo; and by stimulating hepatic glutathione synthesis, it effectively prevents acute acetaminophen-induced hepatotoxicity. By virtue of its free thiol group, acetylcysteine can form stable thiolates with heavy metals and has had limited use in the treatment of poisoning with these agents. As a nucleophile, it can protect against the effects of ionizing radiation and the toxicity of agents such as alkylating cytotoxic drugs and some halogenated hydrocarbons. Inorganic nitrates deplete vascular thiols, and this probably explains the development of tolerance to their hemodynamic effects. Acetylcysteine potentiates the vasodilator action of nitroglycerin and can reverse tolerance to nitrates.
Pharmacokinetics: Acetylcysteine is rapidly absorbed from the gastrointestinal tract and peak plasma concentrations occur about 0.5 to 1 hour after oral doses of 200 to 600 mg. Some studies indicate dose-dependent pharmacokinetics with peak concentrations, the time taken to reach peak concentrations, and bioavailability increasing with increasing doses. Acetylcysteine may be present in plasma as the parent compound or as various oxidized metabolites such as N-acetylcysteine, N,N-diacetylcysteine, and cysteine either free or bound to plasma proteins by labile disulfide bonds or as a fraction incorporated into protein peptide chains. In a study, about 50% was in a covalently protein-bound from 4 hours after a dose. Oral bioavailability is low and mean values have ranged from 4 to 10% depending on whether total acetylcysteine or just the reduced forms are measured. It has been suggested that acetylcysteine's low oral bioavailability may be due to metabolism in the gut wall and first-pass metabolism in the liver. Renal clearance may account for about 30% of total body clearance. On intravenous dosage, mean terminal half-lives have been calculated to be 1.95 and 5.58 hours for reduced and total acetylcysteine, respectively; the terminal half-life of total acetylcysteine was 6.25 hours after oral doses.
For the respiratory infections characterised by thick and viscous hypersecretions such as acute bronchitis, chronic bronchitis and its exacerbation, pulmonary emphysema, mucoviscidosis and bronchiectasis.
For the prevention or lessening of hepatic injury which may occur following the ingestion of a potentially hepatotoxic quantity of acetaminophen. It is essential to initiate treatment as soon as possible after the overdose and, in any case, within 24 hours of ingestion.
Acetylcysteine given orally as effervescent tablets dissolved in water, in a usual dose of 600 mg daily as a single dose or in 3 divided doses.
In case of overdosage, the treatment should be symptomatic.
As an Antidote for Acetaminophen Overdose: As a loading dose of 140 mg/kg orally, followed by 70 mg/kg orally for every 4 hours for 17 additional doses is the standard protocol.
Acetylcysteine (Mucocystein) is contraindicated in patients with hypersensitivity or previous anaphylactoid reactions to acetylcysteine or any components in the preparation.
Acetylcysteine should be used with caution in asthmatic patients. It should also be used with caution in patients with a history of peptic ulcer disease, both because drug-induced nausea and vomiting may increase the risk of gastrointestinal hemorrhage in patients predisposed to the condition, and because of a theoretical risk that mucolytics may disrupt the gastric mucosal barrier.
Use in Pregnancy: Category B. No evidence of impaired fertility or harm to the fetus due to acetylcysteine. There are, however, no adequate and well-controlled studies in pregnant women. Because animal reproduction studies may not always be predictive of human response, this drug should be used during pregnancy only if clearly needed.
Use in Lactation: It is not known whether this drug is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when acetylcysteine is administered to a nursing woman.
Hypersensitivity reactions have been reported in patients receiving acetylcysteine, including bronchospasm, angioedema, rashes and pruritus, edema, urticaria; hypotension, or occasionally hypertension, may occur. Other adverse effects reported with acetylcysteine including flushing, nausea and vomiting, fever, syncope, sweating, arthralgia, blurred vision, disturbances of liver function, acidosis, convulsions, and cardiac or respiratory arrest. Haemoptysis, rhinorrhoea, and stomatitis have been associated with inhalation of acetylcysteine.
Drug stability and safety of acetylcysteine when mixed with other drugs have not been established.
Store at temperatures not exceeding 30°C. Protect from light.
R05CB01 - acetylcysteine ; Belongs to the class of mucolytics. Used in the treatment of wet cough.
Effervescent tab 600 mg x 20's.