Nirmatrelvir, a potent and highly specific inhibitor targeting the main protease of SARS-CoV-2, in conjunction with ritonavir—a Cytochrome P450 3A4 (CYP3A4) inhibitor employed as a pharmacokinetic enhancer—constitutes an orally bioavailable antiviral agent (PAXLOVIDTM; Pfizer Inc., Tokyo, Japan) and has attained Emergency Use Authorization (EUA) in the United States for the treatment of COVID-19 [17]. The gene discussed is CYP3A4; the disease is COVID-19.