A comparative study on the cytogenetic activity of three benzodiazepines in vitro

Even though benzodiazepines (BDZs) possess a leading place among drugs used as anxiolytics, sedatives, muscle relaxants, and anticonvulsants, their cytogenetic effects have not been widely studied in humans. Alprazolam (AZ), bromazepam (BZ), diazepam, and lorazepam (LZ) are some of the most commonly prescribed BDZs. Previous positive findings on diazepam's cytogenetic effects in human lymphocytes suggested additional investigation. In the present research, we explored the cytogenetic potential of AZ, BZ, and LZ in human lymphocyte cultures, using an expanded sample set, administering the under-investigation medications at final concentrations equivalent to oral dosage. As a biomarker of genotoxicity we used sister chromatid exchanges, one of the most sensitive methods reflecting DNA damage and/or subsequent DNA repair, and as a marker of cytostaticity we estimated the proliferation rate index. After 72 h of incubation in the cultures, all three BDZs caused a concentration-dependent, statistically significant increase of sister chromatid exchange frequency (p < 0.001) followed by a statistically significant decrease of proliferation rate index (p < 0.001) of lymphocytes. Our conclusive results suggest that AZ, BZ, and LZ, at concentrations equivalent to oral doses, exhibit statistically significant genotoxicity in human lymphocyte cultures.