Patients with hypertension, coronary artery disease, atrial fibrillation, and hyperlipidemia should pay close attention to what follows if they are considering starting the drug as they likely will need to stop or modify their cardiac medications and monitor their blood pressure and heart rates closely while taking it.
Paxlovid contains ritonavir-boosted nirmatrelvir.
Ritonavir has long been used to increase the levels of anti-HIV medications by strongly inhibiting the cytochrome P450 (CYP) 3A system which metabolizes many cardiac (and non-cardiac) drugs including nirmatrelvir, the active anti-SARS-CoV2 antiviral.
The EUA for Paxlovid makes it clear how important it is for patients and physicians to be aware of these powerful drug interactions:
Clinicians who are not experienced in prescribing ritonavir-boosted drugs should refer to resources such as the EUA fact sheet for ritonavir-boosted nirmatrelvir (Paxlovid) and the Liverpool COVID-19 Drug Interactions website for additional guidance. Consultation with an expert (e.g., clinical pharmacist, HIV specialist, and/or the patient’s specialist provider[s], if applicable) should also be considered.
Since it’s not mentioned elsewhere, there’s a good article from the Skeptical Cardiologist on paxlovid drug interactions. A lengthy quote:
https://theskepticalcardiologist.com/2022/01/07/the-new-covid-19-pill-paxlovid-interacts-with-many-medications-cardiac-patients-take-note/