Therapeutic Window (Therapeutic Index)

The therapeutic window is also known as the therapeutic index (TI), safety window, or therapeutic ratio. It is a research comparison of the range of a therapeutic agent from the level that causes the therapeutic effect to the level that causes toxicity.

Basically, it is a measurement of the range between the smallest amount of a medication that is effective in treating the condition that it is aimed at to the point where the medication becomes toxic and dangerous to the subject. This is used to identify the therapeutic levels of a medication for use and to identify at what level of dosage the therapeutic agent becomes dangerous and toxic.