NAC in COVID Dosing

Inpatient protocol = 150 mg/kg/day divided q4hrs (25 mg/kg q4hrs rounded up to nearest 600 mg)

Why 150 mg/kg/day:

• NAC dosing calculations based on replacing glutathione (GSH) turnover in patients with acetaminophen (APAP) toxicity = 6 mg/kg/hr = NAC 144 mg/kg/day (Rumack & Bateman 2012)

  • • FDA "safety factor" wanting NAC to increase PO protocol for APAP toxicity to PO NAC 420 mg/kg/day x 3 days (Rumack & Bateman 2012); IV protocol 300 mg/kg/day x 1 day

• case report of adjuvant treatment of H1N1 pneumonia with NAC 100 mg/kg/day (Lai et al 2010)

Why rounded up to nearest 600 mg

• ready availability of 600 mg capsules of acetylcysteine

Why q4hrs:

• half-life of NAC ~5.5 hrs

70 kg patient receives 1800 mg q4hr = 10,800 mg/day

Outpatient protocol = 2400 mg x 1; then 1200 mg PO BID x 2 weeks

Reasoning

• Dosing for attenuation of influenza symptoms = NAC 600 mg BID given prophylactically/longterm prior to contracting illness (De Flora et al 1997)

• Dosing for longterm management of COPD/exacerbations = NAC 600 mg BID (Sanguetti 2016)

• Increased dose to account for patients already being symptomatic; adjusted for inpatient calculations above

• ready availability of 600 mg capsules of acetylcysteine

Outpatients take 1200 mg BID = 2400 mg/day