Acetylcysteine is used for its mucolytic activity in respiratory disorders associated with acute cough. It can be given by nebulisation of 3 to 5mL of 20 % solution or 6 to 10mL of a 10 % solution through a face mask or mouthepiece 3 or 4 times daily.

Acetylcysteine has been given by mouth in doses of 200mg two or three times daily as granules or effervescent dissolved in 30mL of water.

Children aged 1 month to 2 years may be given 100mg twice daily, and those aged 2 to 7 years 200mg twice daily.

Acetylcysteine is given by intravenous infusion or by mouth in the treatment of paracetamol poisoning.

If given intravenously: 150mg/kg of acetylcysteine in 200mL of glucose 5 % is given initially over 15 minutes, followed by infusion of 50mg/kg in 500mL of glucose 5 % over the next 4 hours and then 100mg/kg in one litre of glucose 5 % over the next 16 hours. Sodium chloride 0.9 % may be used where glucose 5 % is unsuitable.

Burns, children with inhalation injury who are treated with aerolised heparin 5000 units alternating with 3mL of 20 % acetylcysteine solution, inhaled every 2 hours for the 1st 7 days after injury, appeared to have significantly reduced mortality and reintubation rates compared with historical control.