Is it Safe to Take Paxlovid with My Other Medications?

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In December 2021, the FDA granted emergency use authorization for Paxlovid, which is a combination medication containing nirmatrelvir and ritonavir. It is currently authorized to treat individuals with mild to moderate COVID-19 infection who are at risk for developing severe disease. This includes older adults and people with medical conditions such as heart or lung disease, diabetes, or an abnormal immune system. Paxlovid is an oral medication that is taken twice a day for 5 days.

Nirmatrelvir works by preventing replication of the COVID-19 virus after it enters human cells, but nirmatrelvir is quickly broken down by the body. Ritonavir is a medication that slows the breakdown of nirmatrelvir so the body can do its job. Ritonavir has been used in a similar way to prevent the breakdown of antiviral medications used to treat HIV infection. Ritonavir has no known activity against the COVID-19 virus itself. Paxlovid is well tolerated by most individuals, and the most commonly reported adverse effects include a bad taste in the mouth, diarrhea, high blood pressure, and body aches. As an oral medication, Paxlovid is easier to administer than other treatments, such as monoclonal antibodies, that can only be given by injection.

While Paxlovid is a promising medication for the treatment of COVID-19, there is concern that it interacts with multiple commonly used medications. This is because the ritonavir component of Paxlovid does not only prevent the breakdown of nirmatrelvir, but it also prevents the breakdown of other medications. Increased levels of these other medications may develop, causing toxic effects. Paxlovid can cause serious drug interactions with medications for abnormal heart rhythm, psychiatric medications, blood thinners, gout medications, chemotherapy drugs, blood pressure medications, HIV medications, cholesterol medications, and certain herbal supplements. Depending on the medication involved, drug interactions can cause people to develop abnormal heart rhythms, low blood pressure, bleeding, or other unwanted symptoms.

Prior to taking Paxlovid, tell your doctor about any medications you are taking, including prescription and over-the-counter (OTC) medicines, and any herbal or dietary supplements. Depending on the medications you are taking, your doctor will weigh the risks and benefits of prescribing Paxlovid. Your doctor may decide to lower the dose of your regular medication or have you stop taking it altogether. In some cases, your doctor may decide to prescribe another treatment, such as monoclonal antibodies, as a safer option. Lowering the dose of Paxlovid is not recommended because it will be less effective in treating COVID-19 infection.

Take Paxlovid exactly as prescribed. If you suspect someone has taken Paxlovid inappropriately or is having an adverse effect to the medication, do not make the person vomit. Get an immediate personalized recommendation online or call Poison Control at 1-800-222-1222. Both options are free, confidential, and available 24 hours a day.

Maryann Amirshahi, PharmD, MD, MPH, PhD
Medical Toxicologist