Nirmatrelvir-Ritonavir (Paxlovid): uses, side effects & brands

Written & medically reviewed by Dr. Sanjay Anbu, MBBS · Last reviewed 5 November 2026

Paxlovid is an oral antiviral for early COVID-19; it has many drug interactions. It belongs to the COVID-19 antiviral group. These reduce the severity of COVID-19, working best when started early in high-risk people.

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Drug type — dosing is set by your doctor

Measure	Range
Drug class	COVID-19 antiviral
Type	Prescription
Dose	Individual — ask your doctor or pharmacist

What it is used for

Mild-to-moderate COVID-19 in people at high risk of severe illness
Reducing the risk of hospital admission and death from COVID-19
Started within the first few days of symptoms

Common brand names

India: Paxista, Primovir
Worldwide: Paxlovid

Common side effects

Altered or metallic taste
Diarrhoea
Nausea or vomiting
Headache

Before taking it — precautions

Many drug interactions: tell your doctor about every medicine, including statins, blood thinners, heart-rhythm, seizure and herbal medicines such as St John's wort
Kidney disease changes the dose, and it is not used in severe liver disease
It can make hormonal birth-control pills less reliable; use an extra method such as condoms

When to see a doctor urgently

Severe allergic reaction or severe skin rash (urgent)
Yellow skin or eyes, dark urine, or pain in the upper right belly
Worsening breathlessness (urgent; needs hospital care)

Not a prescription — no dose shown. The right dose of nirmatrelvir-ritonavir depends on age, weight, kidney/liver function and the condition, so MedDroid does not show a dose here. Always get your dose from a doctor or pharmacist and the leaflet inside the pack. General educational information only.

Frequently asked questions

Why does Paxlovid interact with so many medicines?

It contains ritonavir, which slows the liver's clearing of many drugs. Your doctor may pause or adjust some of your medicines during the course.

What is Paxlovid rebound?

In some people, symptoms or a positive test return a few days after finishing. It is usually mild, but follow isolation advice and tell your doctor.

Is the bad taste normal?

Yes, a bitter or metallic taste is common and goes away after the course ends.

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Sources & further reading

Reviewed by Dr. Sanjay Anbu, MBBS. MedDroid is an AI medical assistant and can make mistakes. It provides general health information, not a diagnosis or medical advice — always consult a qualified clinician. In an emergency, contact your local emergency number immediately.