Nirmatrelvir (Paxovir)

Each combipack contains-

• 4 Nirmatrelvir Tablets (each tablet contains Nirmatrelvir INN 150 mg) and
• 2 Ritonavir Tablets (each tablet contains Ritonavir USP 100 mg)

Indicated for mild-to-moderate COVID-19 positive adult and pediatric patients (12 years of age and older weighing at least 40 kg), who are at high risk for progression to severe COVID-19, including hospitalization or death.

This inhibits the main protease (Mpro) of the SARS-CoV-2. This main protease (Mpro) is also referred as 3C-like protease (3CLpro) or nsp5 protease. This inhibition of Mpro hampers the peptidomimetic activity of SARS-CoV-2. Ritonavir is an HIV-1 protease inhibitor but is not active against SARS-CoV-2 Mpro. Ritonavir inhibits the CYP3A mediated metabolism of Nirmatrelvir, resulting in increased plasma concentrations of Nirmatrelvir

Nirmatrelvir must be co-administered with Ritonavir. Initiate this treatment as soon as possible after diagnosis of COVID-19 and within 3-5 days of symptom onset. Administer orally with or without food.

Dosage: 300 mg Nirmatrelvir (two 150 mg tablets) with 100 mg Ritonavir (one 100 mg tablet), with all three tablets taken together twice daily for 5 days.

Missed Dose: If the patient misses a dose of this within 8 hours of the time it is usually taken, the patient should take it as soon as possible and resume the normal dosing schedule. If the patient misses a dose by more than 8 hours, the patient should not take the missed dose and instead take the next dose at the regularly scheduled time. The patient should not double the dose to make up for a missed dose.

Co-administration of this tablet with drugs highly dependent on CYP3A for clearance and for which elevated plasma concentrations are associated with serious and/or life-threatening events is contraindicated. Co-administration with other CYP3A substrates may require a dose adjustment or additional monitoring. Nirmatrelvir and Ritonavir are CYP3A substrates; therefore, drugs that induce CYP3A may decrease Nirmatrelvir and Ritonavir plasma concentrations and reduce this tablet therapeutic effect.

• History of clinically significant hypersensitivity reactions to the active ingredients (Nirmatrelvir or Ritonavir) or any other components.
• Co-administration with drugs highly dependent on CYP3A for clearance and for which elevated concentrations are associated with serious and/or life-threatening reactions.
• Co-administration with potent CYP3A inducers where significantly reduced Nirmatrelvir or Ritonavir plasma concentrations may be associated with the potential for loss of virologic response and possible resistance.

Adverse events (incidence >1% and subject difference) were dysgeusia, diarrhea, hypertension, and myalgia.

This is not recommended during pregnancy and in people who can become pregnant and who are not using contraception. Breastfeeding should be interrupted during treatment. These recommendations are because laboratory studies in animals suggest that high doses of this may impact the growth of the fetus. This drug should be used during pregnancy only if clearly needed and the benefit outweighs the risk to the fetus; use of oral solution is not recommended.

The concomitant use of this tablet and certain other drugs may result in potentially significant drug interactions. Consult the full prescribing information prior to and during treatment for potential drug interactions.

Hepatotoxicity: Hepatic transaminase elevations, clinical hepatitis, and jaundice have occurred in patients receiving Ritonavir.

HIV-1 Drug Resistance: This tablet use may lead to a risk of HIV-1 developing resistance to HIV protease inhibitors in individuals with uncontrolled or undiagnosed HIV-1 infection.

Pediatric Use: This tablet is not authorized for use in pediatric patients younger than 12 years of age or weighing less than 40 kg. The safety and effectiveness of this tablet have not been established in pediatric patients.

Geriatric Use: Clinical studies of this tablet include subjects 65 years of age and older and their data contributes to the overall assessment of safety and efficacy.

Renal Impairment: No dosage adjustment is needed in patients with mild renal impairment. In patients with moderate renal impairment (eGFR >30 to <60 mL/min), reduce the dose of This tablet to 150 mg Nirmatrelvir and 100 mg Ritonavir twice daily for 5 days. This tablet is not recommended in patients with severe renal impairment (eGFR <30 mL/min).

Hepatic Impairment: No dosage adjustment of this tablet is needed for patients with either mild (Child-Pugh Class A) or moderate (Child-Pugh Class B) hepatic impairment. This tablet is not recommended in patients with severe hepatic impairment (Child-Pugh Class C).

Treatment of an overdose of this tablet should consist of general supportive measures including monitoring of vital signs and observation of the clinical status of the patient. There is no specific antidote for overdose with this tablet.

Do not store above 30°C. Keep in a dry place. Protect from light and keep out of the reach of children.