Prazoles demonstrate minimal toxicity. CLIX-FZ BL (A) and A549 (B) cells were exposed to DMSO, doxycycline (Dox [A]), or Dox plus prazoles (T, tenatoprazole; I, ilaprazole; R, rabeprazole) and harvested 24 h later for assessment of viability using the WST-1 assay. NS, not significant. Error bars show SEM for technical triplicates. The experiment was performed twice.