Dental abnormalities in rats after a single large dose of cyclophosphamide

Delayed drug-related mortality in rats treated with a single high dose (75 mg/kg) of cyclophosphamide complicated experiments using this drug treatment. We observed that this delayed mortality was due to dental abnormalities including broken teeth, absent teeth, extra long teeth, and/or supernumerary teeth. These dental abnormalities developed about 140 days after treatment and, if left untreated, interfered with eating. Eventually, the untreated rats starved. Clipping their long teeth and feeding the rats powdered chow eliminated the deaths. Researchers should be aware that high doses of cyclophosphamide may result in dental abnormalities several months after the treatment.