In a bioassay for carcinogenicity, rats and mice of both sexes were treated with tolazamide for 103 weeks at low and high doses. No evidence of carcinogenicity was found.
Pregnancy Category C
Tolazamide, administered to pregnant rats at ten times the human dose, decreased litter size but did not produce teratogenic effects in the offspring. In rats treated at a daily dose of 14 mg/kg no reproductive aberrations or drug related fetal anomalies were noted. At an elevated dose of 100 mg/kg per day there was a reduction in the number of pups born and an increased perinatal mortality. There are, however, no adequate and well-controlled studies in pregnant women. Because animal reproduction studies are not always predictive of human response, tolazamide is not recommended for the treatment of the pregnant diabetic patient. Serious consideration should also be given to the possible hazards of the use of tolazamide in women of child bearing age and in those who might become pregnant while using the drug.
Because recent information suggests that abnormal blood glucose levels during pregnancy are associated with a higher incidence of congenital abnormalities, many experts recommend that insulin be used during pregnancy to maintain blood glucose levels as close to normal as possible.