Taking too little of a drug won't be effective whereas too much can cause adverse side effects. For example, low doses of anti-seizure medication might not prevent a seizure and expired antibiotics might not eliminate an infection. In some cases, the chemical make-up of the medication actually changes over time. The acetylsalicylic acid in aspirin, for example, turns into acetic acid, the main ingredient in vinegar. To ensure the shelf life of medications, don't put them in your bathroom medicine cabinet, says Tsourounis.
Bathrooms tend to have high levels of humidity, which can decrease a drug's potency.
Another bad place is the glove compartment of your car, as heat can destroy a drug's strength as well. She also stresses the importance of keeping medication in the containers they came in. Amber-colored containers protect drugs from light and glass vials keep out oxygen, elements that can decompose the active ingredients. It's fine to use a weekly pill organizer because of the short duration of time the medication is improperly stored, says Tsourounis. Nitroglycerin tablets are the exception, since they must be kept in their original glass container.