Des Moines, IA (written by Tony Leys/Des Moines Register) -- Feeling a little under the weather? If so, it could be that the recent string of triple-digit temperatures gripping much of the country has weakened your medications or affected how your body reacts to them.
Extreme heat can take a toll on medications and on the people who use them, pharmacists say.
Most medicines are designed to be stored at normal room temperatures, which are roughly less than 80 degrees, Drake University pharmacy professor Geoff Wall said. Higher temperatures can change the chemical composition of many drugs.
"They're probably not going to turn into anything dangerous, but they may lose some of their effectiveness," said Wall, who also practices at Iowa Methodist Medical Center.
Wall said some medications are particularly susceptible to heat. Those include nitroglycerin, which is used to treat heart ailments, and insulin, which is for diabetes. Both tend to be carried constantly by patients, who need to take them when they suffer chest pains or high blood sugar. Some diabetics counter this by storing insulin in small coolers, Wall said. Pharmacists recommend that heart patients get new nitroglycerin pills every few months to make sure they're still potent.
Medications kept at home can be harmed by heat if residents lack air conditioning. Wall recommends keeping drugs in the coolest part of a home, as long as they're out of the reach of small children and pets.
Some medications are supposed to be refrigerated, but many are not. Refrigerators have high humidity, which can damage many medicines, said Mary Ross, assistant director of the pharmacy at University of Iowa Hospitals in Iowa City. She recommends refrigerating a drug only if the package says to do so.
Ross said one of the worst places to leave medications is in a closed car. "You wouldn't leave milk in the car -- or even a candy bar," she said. Drugs that are close to their expiration dates are most likely to lose their potency in the heat, she said. Some pills may change color or crumble as they degrade, and capsules may melt, she said. But the damage isn't always visible. People who are worried about possible problems should consult their pharmacist or drug manufacturer.
Ross also warned that problems can crop up when consumers receive medications via mail order. She said such customers should request that their orders be sent by an overnight service, and that they be delivered at a time when someone will be home to accept the package instead of letting it sit outside for hours. She said her hospital and other suppliers sometimes include dry ice or other measures in a package when shipping particularly susceptible medications, but such precautions aren't foolproof.
The heat also can cause trouble for patients taking some medicines. For example, Wall said common types of antihistamines, such as Benadryl, often lessen people's ability to sweat, making it harder for them to cope with summer's fury. Diuretics, such as Lasix or hydrochlorothiazide, cause people to urinate more. Those pills, given for conditions such as high blood pressure or kidney problems, can leave patients more susceptible to dehydration.
Ross noted that some other drugs, including some common antibiotics, can leave patients susceptible to sunburn. She urges patients to heed warnings about the side effects before exposing themselves to sun.
"If you're out there just a small amount of time, you can get burned really badly, with blisters and everything," she said.
Both experts emphasized that anyone with questions about medications should talk to their pharmacists. Before stopping or cutting down on a drug, patients should talk to their physicians.