therapeutic window

noun

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 effective

—Genesis Report-RX