JAK inhibitors carry a black box warning for which events?

• A. Cardiovascular events (MI, stroke, VTE)
• B. Liver toxicity
• C. GI bleeding
• D. Renal failure

Answer: (A)

JAK inhibitors carry a boxed warning because they can increase the risk of serious cardiovascular events and venous thromboembolism. Blocking the JAK-STAT pathway reduces inflammatory signaling, but it also appears to affect clotting and vascular risk in susceptible patients. In clinical trials and postmarketing experience, signals emerged for myocardial infarction, stroke, and DVT/PE, especially in older patients or those with cardiovascular risk factors. Because of this, clinicians carefully assess cardiovascular risk before starting therapy, monitor patients for signs of heart attack, stroke, or clots, and discuss these risks with patients. Liver toxicity, GI bleeding, and renal failure are not the primary boxed-warning concerns for this class, though liver enzymes and other adverse effects are monitored as part of routine safety.