Drug Interaction Report

MONITOR CLOSELY: Coadministration of baricitinib with other immuno- or myelosuppressive agents may potentiate the risk of infections as well as lymphoma and other malignancies. Serious and sometimes fatal infections due to bacterial, mycobacterial, invasive fungal, viral, or other opportunistic pathogens have been reported in patients receiving baricitinib, most of whom were taking concomitant immunosuppressants such as methotrexate or corticosteroids. The most common serious infections reported with baricitinib treatment include pneumonia, herpes zoster, and urinary tract infection. Opportunistic infections include tuberculosis, multidermatomal herpes zoster, esophageal candidiasis, pneumocystosis, acute histoplasmosis, cryptococcosis, cytomegalovirus, and BK virus. Lymphoma and other malignancies have also been observed with baricitinib use, with or without concomitant immunosuppressants.

MANAGEMENT: Close monitoring for the development of infection is recommended if baricitinib is used in combination with other immuno- or myelosuppressive agents, including the possible development of tuberculosis in patients who tested negative for latent tuberculosis infection prior to initiating therapy. Lymphocyte and neutrophil counts as well as hemoglobin should be evaluated at baseline and regularly during therapy, and baricitinib dosage adjusted as necessary in accordance with the product labeling. Patients should be advised to contact their physician if they develop signs and symptoms of infection such as fever, chills, diarrhea, sore throat, muscle aches, shortness of breath, blood in phlegm, weight loss, red or inflamed skin, body sores, and pain or burning during urination. If a serious infection, an opportunistic infection, or sepsis develops, baricitinib should be interrupted until the infection is controlled.

Food may have variable effects on the oral bioavailability of zidovudine. Fatty foods have been reported to decrease the rate and extent of zidovudine absorption following oral administration. In a study of 13 AIDS patients, mean peak plasma concentration (Cmax) and area under the concentration-time curve (AUC) of zidovudine were 2.8 and 1.4 times higher, respectively, in fasting patients than in those administered the medication with breakfast. In addition, variations in plasma zidovudine concentrations were increased when administered in the fed state. In another study of eight patients, the time to reach peak concentration (Tmax) was increased from 0.68 to 1.95 hours, and Cmax was reduced by 50% when zidovudine was administered with a liquid high-fat meal relative to fasting. Protein meals can also delay the absorption and reduce the Cmax of zidovudine, although the extent of absorption is not significantly affected. The clinical significance of these alterations, if any, is unknown. The product labeling states that zidovudine may be taken with or without food.