Generic
Nirmatrelvir + Ritonavir
5 brands available in the market
At a glance
Nirmatrelvir + Ritonavir is an antiviral for mild-to-moderate COVID-19. Nirmatrelvir inhibits SARS-CoV-2 main protease (Mpro) and Ritonavir is a CYP3A inhibitor that increases nirmatrelvir plasma concentrations.
Description
Nirmatrelvir is a Peptidomimetic inhibitor of SARS-CoV-2 main protease (Mpro/3CLpro/nsp5 protease). Inhibition prevents processing of viral polyprotein precursors, stopping viral replication. Ritonavir is an HIV-1 protease inhibitor but is not active against SARS-CoV-2 Mpro; it inhibits CYP3A-mediated metabolism of nirmatrelvir to increase its plasma concentrations.
Indications
- Mild-to-moderate COVID-19 in adults and pediatric patients (12 years+, ≥40 kg) with positive SARS-CoV-2 test and at high risk for progression to severe COVID-19
Therapeutic class
Anti-viral Drugs
Pharmacological class
SARS-CoV-2 Main Protease Inhibitor + CYP3A Inhibitor
Pharmacology
Nirmatrelvir binds to SARS-CoV-2 Mpro enzyme to inhibit viral polyprotein processing, stopping viral replication. Ritonavir inhibits CYP3A enzyme to increase nirmatrelvir plasma concentrations.
Mechanism of action
Treats COVID-19 by inhibiting SARS-CoV-2 viral replication.
Dosage
Adults and Children (12 years+, ≥40 kg):
- 300 mg Nirmatrelvir (2 x 150 mg) + 100 mg Ritonavir (1 tablet), taken together twice daily for 5 days
Moderate Renal Impairment (eGFR ≥30-<60 mL/min):
- 150 mg Nirmatrelvir (1 tablet) + 100 mg Ritonavir, twice daily for 5 days
Administration
- May take with or without food
- Take all tablets together
- Start as soon as possible after diagnosis and within 5 days of symptom onset
Missed dose
If you miss a dose, take at next scheduled time; do not take additional dose.
Side effects
Side Effects (>1%):
- Dysgeusia (taste alteration)
- Diarrhea
- Hypertension
- Myalgia
Precautions & warnings
- Potential for drug interactions; review concomitant medications
- Ritonavir may cause hepatic transaminase elevations, clinical hepatitis and jaundice
- Risk of HIV-1 drug resistance in uncontrolled or undiagnosed HIV-1 infection
Contraindications
- Hypersensitivity
- Concurrent use with CYP3A-dependent drugs (where elevated concentrations are serious/life-threatening)
- Concurrent use with potent CYP3A inducers
- Severe renal impairment (eGFR <30 mL/min)
- Severe hepatic impairment (Child-Pugh Class C)
Drug interactions
- Interactions with CYP3A-dependent drugs
- Potent CYP3A inducers may significantly reduce plasma concentrations
Food interactions
Food does not affect absorption.
Use in pregnancy
Use in Pregnancy: No human data on nirmatrelvir in pregnancy; observational studies on ritonavir have not shown increased risk of major birth defects.
Pregnancy Category: C — always consult a doctor before taking during pregnancy.
Use in lactation
Use in Lactation: No data on presence of nirmatrelvir in human or animal milk; consider benefits and risks of breastfeeding.
Pediatric use
Indicated for children 12 years+ and ≥40 kg.
Geriatric use
Elderly may require dose adjustment.
Renal / hepatic impairment
Renal Impairment: eGFR ≥30-<60 mL/min: Dose reduction; eGFR <30 mL/min: Not recommended.
Hepatic Impairment: Severe (Child-Pugh Class C): Not recommended.
Overdose effects
Limited information on overdose; symptomatic treatment.
Storage conditions
Do not store above 30°C; keep in a dry place, protect from light; keep out of reach of children.
Chemical structure
Nirmatrelvir + Ritonavir