Abstract
Nirmatrelvir-ritonavir (Paxlovid) is a brand-new oral antiviral medication for treating mild to severe COVID-19. The Food and Drug Administration (FDA) issued an Emergency Use Authorization (EUA) for ritonavir-nirmatrelvir on December 22, 2021, to treat COVID-19. We describe a case of mild COVID-19 infection who developed severe hyponatremia following the administration of Paxlovid. Clinical and laboratory evaluations suggest SIADH, likely secondary to Paxlovid. The potential side effects of this medication still require further study.