Mutagenicity examination of several non-steroidal anti-inflammatory drugs in bacterial systems.

The mutagenicity of 6 marketed non-steroidal anti-inflammatory drugs (aspirin, flufenamic acid, diclofenac sodium, indomethacin, naproxen and chloroquine) as well as 2 new anti-inflammatory drugs (tenoxicam and carprofen) was examined by using in vitro bacterial systems (repair test and reversion test). None of them was mutagenic on Ames' reversion test. However, they differed in their responses to repair tests. Tenoxicam, carprofen, aspirin, flufenamic acid and naproxen were not mutagenic in either rec- or pol-assays, whereas chloroquine only showed positive results in the pol-assay system. Indomethacin and diclofenac sodium exhibited a slightly stronger inhibitory activity against B. subtilis rec- mutant than against its rec+ counterpart in rec-assay, which was much weaker than AF-2. Thus their mutagenicity was questionable. These results confirm the usefulness of DNA-repair assays as a complementary endpoint to gene mutation in assessing the genotoxic potential of environmental compounds.