Nirmatrelvir/ritonavir (Paxlovid) has been a game changer for high-risk patients with early COVID-19 symptoms but has significant interactions with commonly used cardiovascular medications, a new paper cautions.

COVID-19 patients with cardiovascular disease (CVD) or risk factors such as diabetes, hypertension, and chronic kidney disease are at high risk of severe disease and account for the lion’s share of those receiving Paxlovid. Data from the initial EPIC-HR trial and recent real-world data also suggest they’re among the most likely to benefit from the oral antiviral, regardless of their COVID-19 vaccination status.

“But at the same time, it unfortunately interacts with many very commonly prescribed cardiovascular medications and with many of them in a very clinically meaningful way, which may lead to serious adverse consequences,” senior author Sarju Ganatra, MD, said in an interview. “So, while it’s being prescribed with a good intention to help these people, we may actually end up doing more harm than good.

“We don’t want to deter people from getting their necessary COVID-19 treatment, which is excellent for the most part these days as an outpatient,” he added. “So, we felt the need to make a comprehensive list of cardiac medications and level of interactions with Paxlovid and also to help the clinicians and prescribers at the point of care to make the clinical decision of what modifications they may need to do.”

The paper, published online in the Journal of the American College of Cardiology, details drug-drug interactions with some 80 cardiovascular (CV) medications including statins, antihypertensive agents, heart failure therapies, and antiplatelet/anticoagulants.

It also includes a color-coded figure denoting whether a drug is safe to coadminister with Paxlovid, may potentially interact and require a dose adjustment or temporary discontinuation, or is contraindicated.

Among the commonly used blood thinners, for example, the paper notes that Paxlovid significantly increases drug levels of the direct oral anticoagulants (DOACs) apixaban, rivaroxaban, edoxaban, and dabigatran and, thus, increases the risk of bleeding.

“It can still be administered, if it’s necessary, but the dose of the DOAC either needs to be reduced or held depending on what they are getting it for, whether they’re getting it for pulmonary embolism or atrial fibrillation, and we adjust for all those things in the table in the paper,” said Ganatra, from Lahey Hospital and Medical Center, Burlington, Massachusetts.

When the DOAC can’t be interrupted or dose adjusted, however, Paxlovid should not be given, the experts say. The antiviral is safe to use with enoxaparin, a low-molecular weight heparin, but can increase or decrease levels of warfarin and should be used with close International Normalized Ratio monitoring.

For patients on antiplatelet agents, clinicians are advised to avoid prescribing nirmatrelvir/ritonavir to those on ticagrelor or clopidogrel unless the agents can be replaced by prasugrel.