Drug Interaction Report

MONITOR: Concomitant use of remdesivir with other agents that are known to induce hepatotoxicity may theoretically increase the risk of liver injury. Data from investigational use and clinical studies suggest that remdesivir may be associated with transaminase elevations. Transient treatment-emergent Grade 1 or Grade 2 elevations in alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were observed during multiple-dose Phase 1 studies in healthy volunteers. The mechanism of potential hepatotoxicity is unknown and the contribution of remdesivir is difficult to determine, as transaminase elevations have also been reported as a component of COVID-19, including in patients receiving placebo in clinical trials of remdesivir.

MANAGEMENT: Caution and increased monitoring may be required if remdesivir is given concurrently with other agents associated with liver injury. Hepatic function should be evaluated prior to starting remdesivir and during treatment as clinically appropriate. The manufacturer of remdesivir recommends considering discontinuation of remdesivir if ALT levels increase to greater than 10 times the upper limit of normal. Additionally, the manufacturer recommends discontinuing remdesivir if ALT elevation is accompanied by signs or symptoms of liver inflammation. The labeling of the other agent(s) involved should also be consulted as they may contain dose adjustment or discontinuation recommendations for those agent(s) in the event of hepatotoxicity.

Grapefruit juice may delay the gastrointestinal absorption of clarithromycin but does not appear to affect the overall extent of absorption or inhibit the metabolism of clarithromycin. The mechanism of interaction is unknown but may be related to competition for intestinal CYP450 3A4 and/or absorptive sites. In an open-label, randomized, crossover study consisting of 12 healthy subjects, coadministration with grapefruit juice increased the time to reach peak plasma concentration (Tmax) of both clarithromycin and 14-hydroxyclarithromycin (the active metabolite) by 80% and 104%, respectively, compared to water. Other pharmacokinetic parameters were not significantly altered. This interaction is unlikely to be of clinical significance.