Paxlovid ^*

Paxlovid (generic name: nirmatrelvir and ritonavir) is an oral antiviral medicine developed for the treatment of mild to moderate COVID-19 in adults at increased risk of progressing to severe illness. The treatment combines two active components: nirmatrelvir, which directly targets the SARS-CoV-2 main protease (M^pro) essential for viral replication, and ritonavir, a long-established protease inhibitor that acts as a pharmacokinetic enhancer. Ritonavir slows the breakdown of nirmatrelvir in the liver, ensuring sustained drug exposure and effective plasma levels. Together, these agents limit viral multiplication, reduce viral load, and give the body’s immune system a greater chance to overcome the infection before it worsens. COVID-19, caused by the novel coronavirus SARS-CoV-2, can range from mild symptoms to life-threatening pneumonia, organ failure, or death, particularly in those with underlying conditions such as diabetes, cardiovascular disease, obesity, or compromised immunity. By suppressing the virus early in its lifecycle, Paxlovid helps prevent disease escalation and lowers the risk of hospitalization and mortality. Treatment initiation should occur promptly, ideally within five days of symptom onset, to maximize its therapeutic effect. Clinical studies demonstrated that Paxlovid substantially reduced hospitalization rates in high-risk, non-hospitalized patients when administered in the early stages of infection. Pharmacologically, Paxlovid belongs to the class of antiviral protease inhibitors. Nirmatrelvir works by binding to the viral main protease enzyme, lowering the presence of functional components needed for replication. Without this process, the virus cannot complete its life cycle. Ritonavir, although originally developed as part of HIV therapy, does not contribute direct activity against SARS-CoV-2 at the doses included in Paxlovid. Instead, its role is to slow down metabolism of nirmatrelvir and thereby prolonging its action. Clinicians prescribe Paxlovid only for those who meet defined risk criteria, since many younger and healthier adults recover from COVID-19 without specific antiviral intervention. The medication is not intended as a preventive agent and should not be used in individuals already requiring hospitalization for severe disease. While it has shown effectiveness against circulating variants of SARS-CoV-2, continued monitoring is ongoing to track resistance patterns and variant susceptibility. The decision to prescribe Paxlovid balances expected benefits against possible risks, particularly given its significant potential for drug–drug interactions through ritonavir’s metabolic effects. Overall, Paxlovid represents an important therapeutic option in the management of COVID-19, particularly for those vulnerable to severe outcomes. Its dual mechanism of direct viral inhibition combined with boosted systemic exposure offers a targeted approach to early antiviral intervention.

Dosage

Follow the prescribing doctor’s dosage instructions which are printed on the label. Check with a doctor or pharmacist if there are any doubts regarding the proper dosage and treatment regimen. Paxlovid treatment lasts for 5 days. Tablets should be swallowed whole and may be taken with or without food. The regimen depends on kidney function:

• No kidney disease or mild kidney disease: 2 nirmatrelvir tablets (150 mg each) + 1 ritonavir tablet (100 mg), taken by mouth twice daily (morning and evening).
• Moderate kidney disease: 1 nirmatrelvir (150 mg) + 1 ritonavir (100 mg), taken twice daily.
• Severe kidney disease: Day 1: 2 nirmatrelvir (150 mg each) + 1 ritonavir (100 mg) once daily; Days 2–5: 1 nirmatrelvir + 1 ritonavir once daily.

If a dose is missed and remembered within 8 hours, take it immediately. If more than 8 hours have passed, skip the missed dose and continue with the next scheduled dose. Do not take two doses at once.

Storage

• Keep out of the sight and reach of children.
• Do not use after the expiry date printed on the carton or blister (last day of the stated month).
• No special storage conditions are required; store at normal room temperature.
• Keep tablets in their original packaging until use and dispose of unused medicines appropriately.