Paxlovid

What is Paxlovid?

Paxlovid is a prescription-only oral antiviral medication used to treat COVID-19. It combines two drugs[1]: 

• Nirmatrelvir, which blocks the virus from replicating 

• Ritonavir, which slows the breakdown of nirmatrelvir in the body, boosting its effect 

Taken early in the infection, Paxlovid helps reduce the severity of symptoms and lowers the risk of hospitalisation or serious illness[1]. 

What is Paxlovid used for?

Paxlovid is used to treat early COVID-19 infection in people at high risk of developing severe illness. It helps prevent complications, including hospitalisation and death, especially in those with underlying health conditions[1]. 

How does Paxlovid work?

Paxlovid contains two components that work together to stop the virus from multiplying[1]: 

• Nirmatrelvir blocks a key enzyme the virus needs to replicate 

• Ritonavir slows down the breakdown of nirmatrelvir, allowing it to remain active in the body for longer 

Together, they help limit the spread of the virus within the body. 

Who can take Paxlovid?

Most adults aged 18 years and older can take Paxlovid, but it is typically offered to people in high-risk groups, such as[1]: 

• Individuals with weakened immune systems (e.g., sickle cell disease, organ transplant recipients, HIV, AIDS, autoimmune and inflammatory conditions) 

• People with chromosomal conditions (e.g., Down’s syndrome) 

• People with chronic health conditions (e.g., diabetes, kidney, lung, or liver disease) 

• People with brain or nervous system conditions 

• Elderly individuals 

To be effective, treatment must begin within five days of the first COVID-19 symptoms and after a confirmed positive test. 

You may not be able to take Paxlovid if you[1]: 

• Are pregnant, trying to get pregnant, or breastfeeding 

• Have ever had an allergic reaction to Paxlovid 

• Have liver or kidney problems 

• Are intolerant to lactose or galactose 

• Have a lactase deficiency or glucose-galactose malabsorption 

The lists above are a summary and do not cover every high-risk situation or condition. Please tell your doctor or pharmacist about any conditions you may have or medication you take before you start treatment, and always follow the instructions in the Patient Information Leaflet[2].  

How do you take Paxlovid?

You should take Paxlovid exactly as prescribed by your doctor, but you should always[1]: 

• Take all three tablets together – two nirmatrelvir and one ritonavir 

• Swallow them whole with water 

• Take your doses 12 hours apart (e.g. 8am and 8pm) 

• Complete the entire five-day course, even if you start feeling better early 

What is the typical dosage of Paxlovid?

Nirmatrelvir comes as 150mg tablets and ritonavir comes as 100mg tablets. Paxlovid is taken twice a day for five days. Each dose consists of[1]: 

• Two tablets of nirmatrelvir (300mg) 

• One tablet of ritonavir (100mg) 

These should be taken together every morning and evening for the full five-day course. 

Can you stop taking Paxlovid?

No, it’s important to finish the full five-day course. Stopping early could allow the virus to rebound and increase the risk of resistance developing[1]. 

What do you do if you take too much Paxlovid?

If you take more than the prescribed amount[1]: 

• Contact NHS 111, your GP, or go to A&E 

• Take the medication packaging with you for reference 

What do you do if you forget to take Paxlovid?

If you miss a dose[1]: 

• Take it as soon as you remember, as long as it’s within 8 hours of the scheduled time 

• If more than 8 hours have passed, skip the missed dose and take the next one at the usual time 

• Do not double up to make up for a missed dose 

What medicines can’t you take with Paxlovid?

Paxlovid can interact with many other medications, which may increase the risk of side effects or reduce effectiveness. Common examples include[1]: 

• Medicines for heart rhythm problems (e.g. amiodarone, flecainide, digoxin) 

• Blood thinners (e.g. apixaban, rivaroxaban, warfarin) 

• Statins used to lower cholesterol (e.g. simvastatin, atorvastatin) 

• Certain antibiotics (e.g. clarithromycin, rifampicin, erythromycin) 

• Antifungals (e.g. itraconazole, ketoconazole) 

• Cancer treatments (e.g. dasatinib, nilotinib) 

• Immunosuppressants (e.g. ciclosporin, tacrolimus) 

• Epilepsy medications (e.g. carbamazepine, phenytoin) 

• Medicines for mental health (e.g. clozapine, quetiapine) 

• Sedatives (e.g. midazolam, zolpidem) 

• Erectile dysfunction medicines (e.g. sildenafil, tadalafil) 

• Steroids used for inflammation (e.g. fluticasone, budesonide, dexamethasone) 

• Colchicine which is used for gout 

• St John's wart, a herbal medication used for low mood 

This is not a full list and so always inform your doctor or pharmacist about all medications and supplements you take before you start a new medicine, and follow the instructions in the Patient Information Leaflet[2]. 

What are the side effects of Paxlovid?

Like all medications, Paxlovid can cause side effects. Most are mild and short-lived. Common ones include[1]: 

• Diarrhoea 

• Vomiting or nausea 

• Altered or metallic taste 

You should contact your GP if you experience any of these symptoms. In rare cases, the medicine may cause a serious allergic reaction (anaphylaxis). You should call 999 or visit A&E immediately if you believe this is happening[1]. 

Symptoms of anaphylaxis include[1]:  

• Difficulty breathing  

• Tightness in throat and chest  

• Swelling of the tongue or throat  

• Feeling faint or dizzy  

• Blue/grey skin or lips  

• Loss of consciousness 

If you experience any side effects, including those not listed, you are encouraged to report them via the Yellow Card Scheme or contact your doctor, pharmacist, or nurse. This information is intended as a summary for general awareness and does not replace professional medical advice. 

The information provided in the side effects section is not a comprehensive list of all possible side effects associated with this medication. For a complete list of side effects, please refer to the Patient Information Leaflet (PIL) provided with your medication or consult your healthcare professional[2]. 

Frequently asked questions about Paxlovid

Can I take Paxlovid if I’m pregnant or breastfeeding? 
Speak to your doctor or pharmacist – treatment decisions are made case by case[1]. 

Can children take Paxlovid? 
It is not generally recommended for use in children[1]. 

Does Paxlovid cure COVID-19? 
No, but it significantly reduces severity and the risk of hospitalisation[1]. 

Can I drink alcohol while taking Paxlovid? 
It’s best to avoid alcohol due to potential interactions[1]. 

For the official NHS guide to Paxlovid, visit their website.