How long should i take diphenhydramine (sleep aid) before discontinuing use? what are the impacts on my health if i do not stop taking?

Keep the dose small.: Diphenhydramine (brand name Benadryl) is an OTC medication generally considered quite safe except for the drowsiness. When used in appropriate doses it is generally without significant adverse reactions. Remember, any drug used to aid in sleep issues should be used only for a short-term. Using this drug occasionally, i.e. 1-2/week should be fine. If taken occasionally there should be no ill-effect