Liver Function Test Monitoring for Paxlovid Treatment

Patient Assessment and Monitoring

For outpatient COVID-19 patients without known liver disease, baseline liver function tests (LFTs) are not mandatory before starting Paxlovid, as the urgency of early antiviral treatment typically outweighs the need for pre-treatment laboratory work, according to the Clinical and Molecular Hepatology guidelines 1, 2, 4
The American Association for the Study of Liver Diseases recommends that hospitalized patients or those with risk factors should obtain baseline LFTs as part of standard COVID-19 assessment, and screen for hepatitis B surface antigen if corticosteroids or immunosuppressants will be used for ≥7 days 5, 4
The European Association for the Study of the Liver suggests monitoring LFTs twice weekly in patients on potentially hepatotoxic medications, and increasing monitoring frequency if abnormal liver function develops 5, 4

For mild elevations (ALT/AST <5× upper limit of normal), the Clinical and Molecular Hepatology guidelines recommend continuing Paxlovid with close monitoring, investigating alternative causes, and considering drug-drug interactions with other medications 1, 3, 2, 5, 4
For moderate-to-severe elevations (≥5× upper limit of normal), the guidelines suggest evaluating for other causes, considering discontinuation if ALT/AST >5× ULN with symptoms or jaundice, and investigating for hepatitis B or C reactivation with serological testing 1, 3, 2, 6

Patients with chronic liver disease require baseline and serial LFT monitoring, and have a higher risk of severe COVID-19 and mortality, according to the Lancet Gastroenterology and Hepatology guidelines 5, 4
Patients with hepatitis B should be screened for HBsAg before initiating immunosuppressive COVID-19 therapies, and antiviral therapy should be initiated or continued to prevent reactivation 5, 4

Delaying Paxlovid initiation in outpatients waiting for LFT results can reduce treatment efficacy, and attributing all LFT abnormalities to medication can overlook COVID-19 itself as a cause of hepatic dysfunction, as noted by the Clinical and Molecular Hepatology guidelines 1, 2
Withholding treatment based solely on abnormal baseline LFTs is not recommended unless there is moderate-to-severe liver injury, according to the Clinical and Molecular Hepatology guidelines 1, 3, 2