Acetylcysteine

It is a mucolytic agent. It is also referred to as N-acetyl, l-cysteine. Here l-cysteine is used as a mucolytic agent that reduces the viscosity of mucus secretions and is a sulfhydryl donor.


Action:
This reduces the viscosity of the festering or non-festering pulmonary secretions and makes it easy for their removal by coughing, postural drainage, or mechanical means.

Its mucolytic effect is thought to be done by free sulfhydryl group which through two way traffic reduce disulfide linkages resulting in a mixed disulfide. This action is effective at pH 7-9.

Therapeutic uses:
1. It is used in the treatment of cough.
2. It is used as antidote for acetaminophen over dosage. Acetylcysteine may protect the liver by maintaining or restoring glutathione levels so that it can metabolize the intermediate metabolite, which is thought to be responsible for liver necrosis.
3. It can also be used in acute and chronic bronchitis.
4. It is used in the prevention of acute renal failure associated with radiographic contrast media. It is thought that this media may reduce anti-oxidant activity. As acetylceyteine is a thiol containing anti-oxidant, so it may increase this activity and helpful in this respect.

Administration and dosage:
Acetylcysteine may be given by nebulization, direct application or intratracheal instillation. The dosage varies according to the dosage form and disease.

Pharmacokinetics:
Orally, Acetylcysteine is absorbed from the GI tract.

Most of the administered drug participates in sulfhydryl disulfide reaction and the remainder is absorbed by the pulmonary epithelium.

It is deacetylated by the liver and subsequently metabolized.

Adverse Effects:
This drug may cause stomatitis, nausea, vomiting, drowsiness or fever. Sometimes GI symptoms may appear.