Discuss the term therapeutic window. Your answer should include its meaning, a quantitative description and an explanation of wide and narrow therapeutic windows.

measure of the relative margin of safety of a drug (for a particular treatment for a typical population) / measure for safe effective treatment;

\(\frac{{{\text{lethal dose (L}}{{\text{D}}_{{\text{50}}}}{\text{)}}}}{{{\text{therapeutic or effective dose (E}}{{\text{D}}_{{\text{50}}}}{\text{)}}}}\) /

ratio of the lethal dose \({\text{(L}}{{\text{D}}_{{\text{50}}}}{\text{)}}\) to the therapeutic or effective dose \({\text{(E}}{{\text{D}}_{{\text{50}}}}{\text{)}}\) / the range of dosage of a drug/its concentration in a bodily system/blood;

Definition of LD₅₀ and ED₅₀ not required for mark.

wide therapeutic window exists for small effective dose and larger lethal dose / toxicity occurs at much higher concentrations than for successful treatment / a big difference between effective and lethal dose / drugs with wide therapeutic window are safer;

narrow therapeutic window requires small doses as lethal dose is not large / OWTTE;

Most candidates gave the description of a therapeutic window, but it was clear that many candidates did not really understand what it means and some confused wide and narrow therapeutic window with wide and narrow spectrum antibiotics.