Acetylcysteine
Prescription status is set country by country — the label where you live is the one that applies.
Beta: the medication section is still being tested, and its data may contain errors. Do not rely on it for a decision about your own treatment.
Acetylcysteine is a mucolytic: it breaks the disulfide bonds that hold thick mucus together, making secretions thinner and easier to clear from the airways. It is also a precursor of glutathione, the body's main detoxifying antioxidant, which is why it is used for liver support as well as for a productive cough.
A usual adult range, not a national label — the dose and the timing differ by country and by product.
Approved uses differ by country — some of these may be off-label or unapproved where you live.
Where an oral mucolytic form is sold, it is taken with food and usually in the morning, and it works only if fluid intake is adequate — thinned mucus still has to be coughed out, and water is what keeps it moving. In Japan the PMDA has approved only an inhalation solution and an oral antidote for paracetamol overdose, so no such cough preparation exists there. It should be separated from antibiotics by a couple of hours, because the two can interact in the stomach and reduce how much antibiotic is absorbed. The taste and the sulfur smell are normal for the molecule; mild stomach upset is the most common complaint.
A cough that keeps getting worse rather than looser, fever, breathlessness or wheeze after a dose, or a rash means it is time to see a doctor rather than continue on one's own.
Reference information, not medical advice. Discuss any change with your doctor.