How much and how often should you use the product?
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 mouthpiece 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 liter of glucose 5 % over the next 16 hours. Sodium chloride 0.9 % may be used where glucose 5 % is unsuitable.
Children with inhalation injury who are treated with aerosolized 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.
Mechanism of actions:
A number of possible mechanisms for the mucolytic activity of acetylcysteine have been proposed. Acetylcysteine’s sulfhydryl groups may hydrolize disulfide bonds within mucin, breaking down the oligomers, and making the mucin less viscous. Acetylcysteine has also been shown to reduce mucin secretion in rat models. It is an antioxidant in its own right but is also deacetylated to cysteine, which participates in the synthesis of the antioxidant glutathione. The antioxidant activity may also alter intracellular redox reactions, decreasing phosphorylation of EGFR and MAPK, which decrease transcription of the gene MUC5AC which produces mucin.
In the case of acetaminophen overdoses, a portion of the drug is metabolized by CYP2E1 to form the potentially toxic metabolite N-acetyl-p-benzoquinone imine (NAPQI). The amount of NAPQI produced in an overdose saturates and depletes glutathione stores. The free NAPQI promiscuously binds to proteins in hepatocytes, leading to cellular necrosis. Acetylcysteine can directly conjugate NAPQI or provide cysteine for glutathione production and NAPQI conjugation.
