Storage And Handling Practice Test

A 71-year-old woman (55 kg) brings in her levothyroxine tablets and says she keeps the bottle on a sunny kitchen windowsill to remember her morning dose. She reports feeling more fatigued over the past month. How does improper storage affect medication efficacy?

A 72-year-old man (76 kg) receives a multi-dose vial of insulin regular (U-100) for subcutaneous use and says he has been using the same vial for "about 3 months" and sometimes leaves the needle in the vial between doses. He reports occasional cloudiness in the vial and mild redness at injection sites. Which handling practice is incorrect for this medication?