Doctors Warn Pfizer COVID Treatment Paxlovid Can Interact With Common Medications

A Pfizer technician handles the company's COVID-19 pill, known as Paxlovid, in a file photograph. Pfizer via AP

The COVID-19 drug Paxlovid can have dangerous interactions with common medications used to treat cardiovascular disease, including certain statins, warned doctors in a new review paper.

A paper published Wednesday in the Journal of the American College of Cardiology shows the combination of nirmatrelvir and ritonavir, or Pfizer’s Paxlovid, can interact with a number of commonly prescribed cardiovascular medications. Ritonavir, first approved to treat HIV in 1996, impacts the CYP450 pathway that’s involved in metabolizing a number of medications—as well as the P-glycoprotein drug efflux pump, according to the paper.

“Co-administration of [Paxlovid] with medications commonly used to manage cardiovascular conditions can potentially cause significant drug-drug interactions and may lead to severe adverse effects,” said an abstract. “It is crucial to be aware of such interactions and take appropriate measures to avoid them.”

The review paper said interactions between Paxlovid and some blood thinners can cause a higher risk of bleeding, and interactions between Paxlovid and cholesterol medications, like statins, can be toxic, according to CNN, citing the research paper. Researchers also warned that certain blood pressure medications combined with Paxlovid can lead to adverse reactions.

“Awareness of the presence of drug-drug interactions of Paxlovid with common cardiovascular drugs is key. System-level interventions by integrating drug-drug interactions into electronic medical records could help avoid related adverse events,” Sarju Ganatra, MD, with Lahey Hospital and Medical Center in Burlington, Massachusetts, and the senior author of the review, told news outlets.

Ganatra added that “Paxlovid could be incorporated into an order set, which allows physicians, whether it be primary care physicians or cardiology providers, to consciously rule out any contraindications to the co-administration of Paxlovid.,” but he said there needs to be “consultation” with health care providers and pharmacists.

“A health care provider’s fundamental understanding of the drug-drug interactions with cardiovascular medications is key,” he said.

Drug Interactions

A U.S. Food and Drug Administration (FDA) fact sheet (pdf) of Paxlovid for health care providers goes into detail about possible drug interactions that can prompt life-threatening reactions.

The medications include but aren’t limited to anti-seizure medications, drugs for irregular heart rhythms, drugs for high blood pressure and high cholesterol, antidepressants and anti-anxiety medications, antidepressants and anti-anxiety medications, steroids, HIV treatments, blood thinners, and erectile dysfunction medications.

“The importance of medication reconciliation before initiation of nirmatrelvir/ritonavir cannot be overemphasized to avoid serious drug-drug interactions,” the authors of the paper wrote Wednesday, referring to Paxlovid.

National Institute of Allergy and Infectious Diseases Director Dr. Anthony Fauci (R) beckons to President Joe Biden in Bethesda, Maryland, on Feb. 11, 2021. Carlos Barria/Reuters

The FDA gave Paxlovid emergency use authorization in late 2021 for the treatment of symptomatic, non-hospitalized adults who have mild to moderate COVID-19 and who are at risk of developing severe symptoms.

But months later, the Centers for Disease Control and Prevention issued an alert saying that health care providers should be on the lookout for a rebound of symptoms, known as “COVID rebound,” after a patient takes Paxlovid, tests negative, and then returns a positive test.

Several high-profile individuals developed “COVID rebound,” including President Joe Biden and White House medical adviser Anthony Fauci, after they took Paxlovid. Both are fully vaccinated and have received booster doses.

When Biden started a course of Paxlovid in July, White House Dr. Kevin O’Connor temporarily took him off Crestor and Eliquis, two heart drugs, so as to not develop an adverse reaction.

Pfizer has not returned a request for comment.