Acetylcysteine is a synthetically produced modification (derivative) of the naturally occurring amino acid cysteine. Acetylcysteine is used as an expectorant in respiratory diseases and as an antidote in paracetamoline intoxication. Its effect as an expectorant has not been fully established. It is administered perorally, by inhalation or parenterally. Most forms of acetylcysteine do not require a prescription.
Pharmacodynamics
The mucolytic effect is apparently due to the cleavage of disulfide bridges present in mucopolysaccharides (a component of mucus). This makes the mucus thinner and easier to cough up. The effect as a paracetamol antidote comes from the metabolization of acetylcysteine to cysteine. Cysteine is required for the formation of glutathione, which plays a major role in the degradation of paracetamol into non-toxic metabolites.
Pharmacokinetics
The bioavailability of acetylcysteine is only 5-10%. This is due to its rapid metabolism to cysteine in the liver. Plasma protein binding is about 83%. The resulting cysteine is absorbed into the body's natural amino acid metabolism and thus metabolized. The half-life is about 5-6 hours.
Interactions
Acetylcysteine should not be taken together with cough suppressants as this inhibits coughing up. Acetylcysteine inactivates some antibiotics (penicillins, aminoglycosides, tetracycline). For this reason, they should be taken 2 hours apart from each other. Acetylcysteine can increase the effect of glycerol trinitrate, which can possibly lead to life-threatening side effects.
Side effects associated with the use of acetycysteine are occasional to rare.
These include:
LD50 (rat, oral): 5050 mg-kg-1
| ATC Code | R05CB01, S01XA08, V03AB23 |
| Formula | C5H9NO3S |
| Molar Mass (g·mol−1) | 163,20 |
| Physical State | solid |
| Melting Point (°C) | 106–108 |
| CAS Number | 616-91-1 |
| PUB Number | 581 |
| Drugbank ID | DB06151 |
Ad
