Abstract
The pharmacokinetics and toxicity of intravenous lonidamine were investigated in dogs receiving four cycles of lonidamine (400 or 800 mg/m2) ± whole-body hyperthermia (WBH). Clearance and volume of distribution in dogs receiving lonidamine during WBH increased 1·6–2·3 and 1·9–3·5-fold respectively, relative to dogs receiving lonidamine under euthermic conditions (p < 0·02). In dogs receiving lonidamine under euthermic conditions or 400 mg/m2 + WBH, the area under the lonidamine concentration versus time curve (AUC) measured during the fourth treatment was 21–58% lower than the first treatment AUC. However, in dogs receiving 800 mg/m2 + WBH, the fourth treatment AUC was four-fold higher than the first treatment AUC (p < 0·02). This suggests repeated exposure to 800 mg/m2 lonidamine and WBH impairs lonidamine metabolism. Weakness, hypoglycaemia, and elevations in amylase, alanine aminotransferase, alkaline phosphatase and bilirubin were more severe or occurred exclusively in dogs receiving 800 mg/m2 + WBH. Since these changes were attributable to marked AUC increases, which occurred secondary to repeated exposure to 800 mg/m2 lonidamine during WBH, 400 mg/m2 was identified as the maximum tolerable dose to be administered intravenously to dogs during WBH.