What Are the Side Effects of Paxlovid?

The use of Paxlovid is strongly recommended by the World Health Organization (WHO) for those with the highest risk of hospital admission due to COVID-19. It has the ability to reduce the risk of hospitalization or death among unvaccinated individuals, immunocompromised people, and those above the age of 65 by almost 90%. 

However, this lifesaving drug might not be recommended to certain individuals who qualify for a prescription due to its potential drug interactions and side effects. Here’s what you should know before taking Paxlovid.

Side Effects of Paxlovid

Like any other medication, Paxlovid may cause some side effects that differ from one individual to another.

Paxlovid is a combination of two different medications—nirmatrelvir and ritonavir—which has few concerning side effects, Lewis Nelson, MD, chair of the department of emergency medicine at Rutgers New Jersey Medical School, told Verywell.

Some of the possible side effects of Paxlovid include the following:

• Allergic reactions
• Liver problems
• Resistance to HIV medicines
• Diarrhea
• Muscle aches
• Altered sense of taste
• High blood pressure

There are anecdotal reports of people experiencing a relapse of COVID-19 symptoms after taking Paxlovid. However, these have yet to be studied further.

“Symptom recurrence is a poorly defined phenomenon that does not appear to be more common than in those who did not take the medication,” Nelson said. “This suggests it is not Paxlovid-related, but more likely COVID-related. It has been suggested that starting the medication too early prevents an adequate immune system response, heightening the possibility of disease recurrence.”

Right now, more research is needed to know if potential cases of symptom recurrence are caused by the timing of Paxlovid intake, high viral load, a poor immune system that was unable to clear the virus, or some other factors.

“We are beginning to see rebounding of symptoms after a five-day course of Paxlovid, but it is still effective for reducing hospitalization and death due to COVID-19,” Mahdee Sobhanie, MD, infectious diseases physician at The Ohio State University Wexner Medical Center, told Verywell. “The rebound symptoms are something we will have to keep a close eye on and try to figure out how to interpret these symptoms.”

Which Medications Interfere With Paxlovid?

The primary concerns with Paxlovid are the potential drug interactions, experts said. Taking Paxlovid with certain medications may cause life-threatening side effects, increase or decrease drug effectiveness, or change the way one or both drugs work.

“It’s important to let your doctor know what other medications you are taking, because the ritonavir component of nirmatrelvir will affect the levels of your home medication in your body,” Sobhanie said.

There are numerous medications that may interact with Paxlovid, including:

• Colchicine
• Alfuzosin
• Carbamazepine
• Ranolazine
• Lovastatin
• Triazolam
• Apalutamide
• Sildenafil
• Dihydroergotamine
• Rifampin

The National Institutes of Health (NIH) has a more comprehensive list of medications that are expected to have drug-drug interactions with Paxlovid. In cases where the risks of the drug interaction outweigh the potential benefits, alternative COVID-19 therapy must be prescribed. If it is clinically appropriate, the medication you’re taking may be temporarily withheld or adjusted.

“There are many medications that are metabolized by a liver enzyme called CYP3A that is inhibited by one of the components of Paxlovid,” Nelson said. “Inhibition of medication metabolism can lead to unpredictable and potentially dangerous blood levels of these other medications.”

Who Should Not Take Paxlovid?

According to Nelson, the following individuals are not recommended to take Paxlovid:

• Individuals without appropriate indications for Paxlovid use
• Those with a known allergy to either component of the combination medication, nirmatrelvir or ritonavir
• Patients with severe liver or kidney disease
  

The WHO also recommends against the use of Paxlovid among patients at lower risk of hospitalization because the benefits of the drug are negligible.

“[Paxlovid] is certainly not a benign medication,” Karen Lin, MD, MS, assistant dean for Global Health and professor in the Department of family medicine and community health at Rutgers Robert Wood Johnson Medical School, told VeryWell. “I usually discuss extensively with patients who might meet criteria, and after discussion, some patients chose not to get it.”

To understand how Paxlovid may affect you, make sure to tell your healthcare provider if you:

• Have a potential drug interaction
• Are pregnant or planning to get pregnant
• Are breastfeeding
• Have liver or kidney disease
• Are taking combined hormonal contraceptives 
• Have untreated HIV infection

It’s crucial that you discuss your medical history with a qualified health professional so they can provide optimal health care and keep you well-informed about the potential impacts of Paxlovid.

“There is still much to learn about COVID, specifically with treatment,” Sobhanie said. “But we are in a better position than we were two years ago due to the use of vaccines, monoclonal antibodies, and antivirals.”

The information in this article is current as of the date listed, which means newer information may be available when you read this. For the most recent updates on COVID-19, visit our coronavirus news page.