Nirmatrelvir 150 mg & Ritonavir 100 mg

Description

Nirmatrelvir 150 mg & Ritonavir 100 mg (Paxlovid) – COVID-19 Treatment, Dosage, Side Effects
1. Composition:
Nirmatrelvir 150 mg Ritonavir 100 mg about Nirmatrelvir 150 mg: A SARS-CoV-2 main protease (Mpro, also known as 3CLpro) inhibitor.
Ritonavir 100 mg: Originally developed for HIV, used here as a pharmacokinetic booster (it inhibits the enzyme that metabolizes nirmatrelvir, increasing its levels in the blood).
2. Indications:
Treatment of mild-to-moderate COVID-19 in adults and pediatric patients (12 years and older, weighing at least 40 kg) who are at high risk for progression to severe COVID-19, including hospitalization or death.
Must be started within 5 days of symptom onset.
3. Mechanism of Action:
• Nirmatrelvir:
Inhibits the main protease (Mpro) of SARS-CoV-2, an enzyme essential for viral replication.
By blocking this enzyme, it prevents the virus from processing polyproteins needed for its replication.
• Ritonavir:
It does not act directly on SARS-CoV-2 but inhibits CYP3A4, an enzyme that metabolizes many drugs including nirmatrelvir.
This inhibition boosts the concentration and effectiveness of nirmatrelvir.
4. Dosage:
300 mg of Nirmatrelvir (two 150 mg tablets) + 100 mg of Ritonavir (one tablet) taken together twice daily for 5 days.
Total of 6 tablets per day (3 in the morning, 3 in the evening).
Note: Dose adjustments may be needed in patients with moderate renal impairment. Not recommended in severe renal or hepatic impairment.
5. Common Side Effects:
Altered taste (dysgeusia)
Diarrhea
High blood pressure
Muscle aches
Liver enzyme elevations
Allergic reactions (rare)
6. Contraindications:
Severe liver or kidney disease
Concomitant use with drugs that are highly dependent on CYP3A for clearance and for which elevated concentrations are associated with serious reactions (e.g., certain antiarrhythmics, sedatives, ergot alkaloids).
Ritonavir has many drug interactions, including with:
Antiarrhythmics
Anticonvulsants
Statins (simvastatin, lovastatin)
Some antipsychotics
St. John’s Wort
7. Use in Special Populations:
Pregnancy: Limited data; use only if potential benefit outweighs risk.
Breastfeeding: Unknown if nirmatrelvir is excreted in human milk.
Children under 12: Not authorized.
Elderly: No dose adjustment solely based on age, but monitor for renal function.
8. Storage:
Store below 25°C (77°F) in the original packaging to protect from moisture.