Mutagenicity tests with phenylbutazone in mammals

The ability of phenylbutazone to induce chromosome aberrations in mammals has been tested in the somatic and germ cells of male BALB/c mice. Induction of chromosomal aberrations was studied in bone marrow cells, 1, 2, 4 and 8 days after i.p. dosing of 400 mg kg phenylbutazone and polychromatic erythrocytes were examined for the presence of micronuclei 30 h after injection. The production of chromosome aberrations in germ cells was tested by the dominant lethality produced in the postmeiotic germ cell stages and the reciprocal translocations induced in the premeiotic one. All the tests yielded negative results. The in vitro observations reported in the literature as well some in vivo studies performed on humans suggest, however, that administration of this compound during long periods of time could result in the induction of chromosome anomalies.