Temperature control
Manufacturers guarantee efficacy when medicine is stored at 68 to 77 degrees, but 58 to 86 degrees is usually fine, Chan says. Outside that range, medications can start to degrade. Biologics, increasingly used to treat arthritis, and hormone-containing drugs, such as thyroid or birth control pills, are especially likely to break down in heat. Insulin is destroyed by both freezing and overheating.

Chan points out that one of the biggest mistakes people make is leaving
medications in a parked car, which can become scorching or frigid in a matter of minutes. "Make the drugstore your last stop of the day," he advises.

At home, be sure to refrigerate drugs that need it. The shelf life of Enbrel vials, for example, is less than seven days at room temperature but significantly longer under refrigeration. The same is true for most drugs that require cold storage.

Chan stresses that glucose meters and diagnostic testing strips are as sensitive to heat, cold, and moisture as medications are. "If these devices are exposed to extreme temperatures, you're not going to get an accurate reading," he says.

Drugs in transit
In summer, the interior of a mailbox can reach more than 130 degrees; in winter, it's an industrial-strength freezer. If you mail order drugs, choose overnight shipping, and if possible, have them sent to your office.

When traveling, always put medications in your carry-on luggage. Baggage can get lost, and baggage holds on airplanes aren't temperature controlled; checked bags can sizzle or freeze on the tarmac. Many manufacturers provide no-cost travel packs for refrigerated medicines.

If the worst happens
Sometimes it's obvious when a pill is altered – the color, texture, or shape has changed – but not always.

If you have any doubts about a medication, contact your pharmacist. As for refrigerated medicine left out for an extended period, contact the manufacturer or discard it and get a new supply.

In the long run, Chan says, the challenge is balancing safe storage with ease of use. "A medication is no help if people can't find it or forget to take it," he says.