1998 Volume 23 Issue SupplementI Pages 37-49
A 2-week toxicity study of magnesium sulfate administered by a 24-hr intravenous infusion at the dosage levels of 0, 12.5, 50, 100 and 200 mg/kg/hr in female beagle dogs was conducted, with 2-week follow-up observation after drug withdrawal. One of 2 animals in the 200 mg/kg/hr group died approx. 32 hr after the start of infusion. At the same time, the remaining 1 animal of the same group was sacrificed in a moribund state. Changes attributable to the treatment of magnesium sulfate were decreased food consumption and body weight gain, anemia, mild prolongation of conduction time in electrocardiogram and tubular basophilia in the kidneys in the animals treated with 100 mg/kg/hr. Furthermore, decreased calcium level was recorded in the animals treated with 50 mg/kg/hr or more. However, these changes disappeared after drug withdrawal, and reversibility was suggested. Judging from the mode of occurrence, since the change in calcium level observed in the group treated with 50 mg/kg/hr was slight, it was considered to be toxicologically insignificant. In conclusion, the nontoxic dosage level of magnesium sulfate was judged to be 50 mg/kg/hr under the condition of the present study.
