therapeutic window

noun

Medical Definition of therapeutic window

1 : the range of dosage of a drug or of its concentration in a bodily system that provides safe effective therapy the narrow therapeutic window…the effect may go from therapeutic to toxic with an increase of just 10 micrograms per milliliter [in] blood concentration— Lisa Davis
2 : a usually short time interval (as after a precipitating event) during which a particular therapy can be given safely and effectively has a narrow therapeutic window: the drug must be given within three hours of a stroke in order to be effectiveGenesis Report-RX