Excessive Heat Can Harm Medications

SATURDAY, Aug. 20 -- Medications can be harmed by high temperatures, say pharmacists.

Although just a handful of drugs have been tested at temperatures above 86F, all medications could be altered by extreme heat, they warn.

According to Dr. Amy Peak, clinical pharmacist and director of Drug Information Services at Butler University, several medications have been tested at high temperatures. She outlined some of the changes the researchers found:

• Albuterol inhalers: The container could burst at temperatures above 120F. Moreover, when stored at high temperatures, there may be a decrease in the amount of medication inhaled.
• Concentrated epinephrine: Cyclical heating could reduce 64 percent of the medication's potency.
• Diazepam: Concentration of this drug dropped 25 percent when stored at 98.6F.
• Formoterol (capsules that are placed in inhalers): Following four hours of exposure to 158F heat, the amount released from the capsules was less than half the normal amount.
• Lorazepam: When stored at 98F, concentration decreased 75 percent.
• Mometasone (formoterol inhalers): Temperatures above 120F may cause the container to burst.

Peak says several more medications may be susceptible to excessive heat, including:

• Insulin: Excessive heat could make the insulinless effective. It could also cause the insulin vials to explode.
• Thyroid hormones: Thyroid hormones could be altered by excessively high temperatures, resulting in inconsistent doses.
• Any medications in aerosolized canisters could burst when exposed to temperatures above 120F.

Although the United States Pharmacopeia Convention Inc. recommends that medications be protected from excessive heat, only a few drugs are actually tested at temperatures above 86F, Peak pointed out.

Nevertheless, she noted there are a number of steps people can take to ensure the quality of their medications during heat waves, including:

• Be aware that temperatures inside cars can top 160 F. When driving, be sure to keep medications out of the trunk and in the climate-controlled passenger compartment.
• Never leave medications in a parked car.
• During heat waves, have medications shipped overnight in special cooled containers.
• Request a one-time replacement from your insurance company or drug manufacturer for any medication that may have been affected by excessive heat.

More information

The National Institutes of Health provides more information on storing medicine safely.

Posted: August 2011