Ibudilast inhibits doxorubicin‐induced cytotoxicity in RAW264.7 macrophage cell line. (a) Schematic flow chart of the high‐throughput screening to identify compounds that can attenuate cytotoxicity caused by doxorubicin treatment. (b) Results of cytoprotection screen. (c) Effect of ibudilast on doxorubicin‐induced cytotoxicity. RAW 264.7 cells were pretreated with or without ibudilast (10 μM) for 30 min before the addition of doxorubicin at 1, 3, 10, and 30 μM. The number of living cells was counted 12 hr after doxorubicin treatment (n = 5). Scale bar: 50 μm. (d) Effect of cAMP analogues (10 μM) on doxorubicin‐induced cytotoxicity in RAW 264.7 cells (n = 5). (e–g) Effect of ibudilast on cisplatin‐induced cytotoxicity (e, n = 6), mitomycin‐induced cytotoxicity (f, n = 6), and methotrexate‐induced cytotoxicity (g, n = 6) in RAW 264.7 cells. Data are shown as the mean ± SEM. *P < .05, significantly different as indicated; one‐way ANOVA with Tukey's comparison test (d) or two‐way ANOVA with Sidak's comparison test (c, e, f, and g)