Acetaminophen interactions with immune checkpoint inhibitors: guilt by association?

Recent studies suggest that acetaminophen may be linked to poorer long-term outcomes in patients receiving immune checkpoint inhibitors. Since acetaminophen is a widely used and essential medication for many patients with cancer, it is important to carefully evaluate the clinical significance of these findings. Using the WHO Causality Assessment and the Drug Interaction Probability Score to evaluate the available evidence, however, it seems unlikely or doubtful that there is a clinically significant interaction between acetaminophen and immune checkpoint inhibitor. We recommend that acetaminophen should not be restricted when used with checkpoint inhibitors until more robust evidence is available.