Core pharmacology

Class Group

Antidote

Legacy Cicm Level

Level 3

Indications Uses

- paracetamol overdose
- non-paracetamol induced fulminant hepatic failure
- prevention of contrast nephropathy
- mucolytic therapy

Chemical Pharmaceutics

Synthetic derivative of cysteine

Presentation

IV or oral formulation
200mg/mL
compatible with 5% dextrose

Main Action

antioxidant and glutathione inducer

Mechanism of action

- Metabolized to cysteine → Regeneration of sulphydril groups and glutathione
- acting as an alternate substrate for conjugation
- reduces disulfide bonds in mucoproteins

Onset Peak Duration

Duration: short

Physiological effects

- Reduces hepatotoxicity
- mucolytic

Adverse Effects Toxicity

usually in 1st hr:
- rash around infusion site
- angiooedema
- bronchospasm
- hypo/hyper tension

Mx: stop, give antihistamine, then restart at slowest infusion rate

Absorption

PO: BA low

Protein binding

66-97%
Albumin

Volume of distribution

0.5 L/kg

Metabolism

Liver
Deacetylated to cysteine -> normal metabolism (Rapid)

Excretion

Unchanged: 40% urine, 3% feces

Half-life

5.5 hrs

Route And Dose

IV, PO, Neb (inhaled)

IV:
1st : 150mg/kg in 200ml dextrose over 15mins
2nd : 50mg/kg in 500ml over 4hrs
3rd : 100mg/kg in 1l over 16hrs