Nirmatrelvir-ritonavir

Background

• Indicated for mild to moderate COVID-19 infection
• Combination medication includes: nirmatrelvir, a protease inhibitor that interferes with viral replication, and ritonavir, which boosts levels of nirmatrelvir by interfering with CYP3A-mediated drug metabolism

Dosing

• Mild-to-moderate COVID-19 (within 5 days of symptom onset): nirmatrelvir/ritonavir 300 mg/100 mg p.o. bid for 5 days

Renal Dosing

• eGFR ≥60 mL/min: no adjustment
• eGFR 30-59 mL/min: 150 mg/100 mg p.o. bid
• eGFR <30 mL/min: 300 mg/100 mg load on day 1, followed by 150 mg/100 mg p.o daily for 4 more days
• Dialysis:
  • Weight ≥40 kg: 300 mg/100 mg load on day 1, followed by 150 mg/100 mg p.o daily for 4 more days
  • Weight <40 kg: 150 mg/100 mg every 48 hours for 3 doses
  • Give after dialysis on dialysis days

Hepatic Dosing

• Child-Pugh class C: contraindicated

Safety

Contraindications

• Hypersensitivity reaction
• Severe liver disease (Child-Pugh Class C)
• Drug-drug interactions (check Liverpool site)