Maximum tolerated dose

The maximum tolerated dose (MTD) is commonly estimated to be the maximum dose that can be administered for the duration of a defined period that will not compromise the survival of the animals by causes other than carcinogenicity. Most commonly this is based on a single/one day administration. If the MTD has been chosen appropriately, there should be no adverse effect on survival, only a modest decrement in body weight gain and minimal overt signs of toxicity. The MTD has been exceeded if there is increased mortality, severe body weight decrement, or marked signs of toxicity. It should be noted that another meaning for MTD has sometimes been ‘minimum toxic dose.’