What are the common side effects of Paxlovid (nirmatrelvir and ritonavir)?

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Last updated: June 14, 2025View editorial policy

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From the Guidelines

Paxlovid (nirmatrelvir and ritonavir) is associated with several common side effects, including altered taste, diarrhea, muscle aches, high blood pressure, and abdominal pain, which are typically mild to moderate and resolve after completing the standard 5-day treatment course. These side effects are well-documented in recent studies, such as the one published in the Annals of Internal Medicine in 2024 1. The most common side effects include:

  • Altered taste (dysgeusia), affecting about 6% of patients
  • Diarrhea, occurring in approximately 3% of patients
  • Muscle aches, high blood pressure, and abdominal pain, each affecting about 1% of patients
  • Nausea, feeling generally unwell, or headaches, which may also occur in some patients The altered taste sensation is thought to occur because the medication is partially excreted in saliva, directly affecting taste receptors. Gastrointestinal side effects like diarrhea and abdominal pain result from the medication's effects on the digestive system. It's essential to note that Paxlovid can interact with many other medications due to ritonavir's strong inhibition of liver enzymes that metabolize drugs, so patients should always inform their healthcare provider about all medications they're taking before starting Paxlovid. Despite these side effects, Paxlovid remains an effective treatment for COVID-19 in high-risk patients, significantly reducing the risk of hospitalization and death, as supported by recent guidelines from the American College of Physicians 1 and the World Health Organization 1.

From the FDA Drug Label

PAXLOVID may cause serious side effects, including: • Allergic reactions, including severe allergic reactions (anaphylaxis) have happened during treatment with PAXLOVID • Liver problems The most common side effects of PAXLOVID include: • altered sense of taste • diarrhea Other possible side effects include: • headache • vomiting • abdominal pain • nausea • high blood pressure • feeling generally unwell

The common side effects of Paxlovid (nirmatrelvir and ritonavir) include altered sense of taste and diarrhea. Other possible side effects are:

  • headache
  • vomiting
  • abdominal pain
  • nausea
  • high blood pressure
  • feeling generally unwell Paxlovid may also cause serious side effects, including allergic reactions and liver problems 2.

From the Research

Common Side Effects of Paxlovid

The common side effects of Paxlovid (nirmatrelvir and ritonavir) include:

  • Dysgeusia (altered taste) 3
  • Diarrhea 3 Other side effects may occur, but the provided studies do not give a comprehensive list of all possible side effects.

Serious Side Effects

Serious adverse events occurred in 1.6% of patients taking nirmatrelvir plus ritonavir, compared to 6.6% of patients taking placebo 3. Adverse events leading to discontinuation of the drugs or placebo occurred in 2.1% of patients taking nirmatrelvir plus ritonavir, compared to 4.2% of patients taking placebo 3.

Efficacy and Safety

Paxlovid has been shown to be effective in reducing the risk of hospitalization and death in patients with COVID-19 4, 5, 6, 3. The efficacy of Paxlovid has been demonstrated in both clinical trials and real-world settings 4, 5, 6. Paxlovid is generally well tolerated, with most adverse events being of mild or moderate severity 5.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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