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

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Last updated: February 20, 2025View editorial policy

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From the Guidelines

Paxlovid can cause several side effects, with the most common being an altered sense of taste (dysgeusia), diarrhea, muscle aches, and high blood pressure, as reported in recent studies 1. The altered taste, often described as a metallic or bitter taste, is the most frequently reported side effect and typically resolves after completing the medication course. Gastrointestinal issues like diarrhea, nausea, and vomiting can occur. Muscle aches and headaches are also possible. Less common but potential side effects include allergic reactions, liver problems, and interactions with other medications. It's crucial to inform your healthcare provider about all medications you're taking, as Paxlovid can interact with many common drugs.

Key Side Effects

  • Altered sense of taste (dysgeusia)
  • Diarrhea
  • Muscle aches
  • High blood pressure
  • Allergic reactions
  • Liver problems
  • Interactions with other medications The standard Paxlovid regimen is two tablets of nirmatrelvir and one tablet of ritonavir taken together twice daily for five days. Always complete the full course as prescribed, even if symptoms improve. These side effects occur because Paxlovid affects viral replication and interacts with liver enzymes. The altered taste is likely due to the medication's excretion in saliva. Most side effects are temporary and resolve after completing treatment. If you experience severe side effects or signs of an allergic reaction (such as difficulty breathing or swelling), seek medical attention immediately. According to recent guidelines 1, the benefits of using Paxlovid in outpatient treatment of adults with confirmed COVID-19 at high risk for progressing to severe disease outweigh the potential risks.

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 side effects of Paxlovid (nirmatrelvir/ritonavir) include allergic reactions, liver problems, altered sense of taste, and diarrhea. Other possible side effects are:

  • headache
  • vomiting
  • abdominal pain
  • nausea
  • high blood pressure
  • feeling generally unwell 2

From the Research

Side Effects of Paxlovid (nirmatrelvir/ritonavir)

The provided studies do not directly discuss the side effects of Paxlovid (nirmatrelvir/ritonavir) in detail. However, some information can be gathered from the studies:

  • One study 3 mentions that there were no significant differences in reported adverse events of neurological disease, liver injury, or kidney injury between patients treated with Paxlovid within 5 days of COVID-19 onset and those treated more than 5 days after onset.
  • Another study 4 notes that Paxlovid interacts with many commonly used drugs, which could be a disadvantage.
  • The same study 4 also mentions that molnupiravir, another antiviral drug, has the potential to mutate host DNA and cause the virus to mutate into variants with new features, but this is not directly related to Paxlovid.

Key Points

  • The studies primarily focus on the effectiveness of Paxlovid in reducing hospitalization and mortality rates among COVID-19 patients, rather than its side effects.
  • Some studies mention the potential interactions of Paxlovid with other drugs, but do not provide a comprehensive list of side effects.
  • Further research is needed to fully understand the side effects of Paxlovid.

Relevant Findings

  • A study 5 found that patients older than 65 years had a significantly higher risk of achieving excessive plasma trough concentrations of nirmatrelvir and ritonavir, which could potentially lead to increased side effects.
  • However, this study does not provide specific information on the side effects experienced by these patients.

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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