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Can extremely cold conditions make your medication less effective?

February 11, 2019; 10:13 AM

Most people are aware of the various impacts that cold weather conditions could have on their health. However, experts say that extreme temperatures, whether low or high, can also affect the efficacy of the medications used to treat certain conditions.

How much a medication can be impacted by exposure to conditions that are far warmer or cooler than what is recommended by the manufacturer tend to vary depending on the medication, according to Jeff Pilz, a specialty practice pharmacist at The Ohio State University Wexner Medical Center.

"Both extreme cold as well as extreme heat that we see in the summertime, or when people have their medication delivered and [the medication is left] inside a truck, a car or a mailbox, certainly can lead to further degradation of the product from what we normally see, or an increased rate of degradation beyond what the manufacturer's expiration date is accounting for," Pilz told AccuWeather.

Capsules - Pixabay image

"This can potentially lead to loss of potency or reduced efficacy of that specific medication," Pilz added.

The types of medications that can become damaged and rendered ineffective if frozen are those that are commonly referred to as 'biologicals,' which are large molecules given by injection, according to Craig K. Svensson, Pharm.D., Ph.D., dean emeritus and professor of medicinal chemistry and molecular pharmacology at the Purdue University College of Pharmacy.

"When a biological like insulin is frozen, the complex structure of the drug changes, which can reduce its effectiveness," Svensson said. "The consequence is that the medication will not control the patient's disease; for example, a diabetic using ineffective insulin will not achieve the control of their blood glucose that is desired."

Unopened insulin is best stored and refrigerated at temperatures between 36 and 46 degrees Fahrenheit, according to Consumer Med Safety. Experts say that insulin that has been frozen should not be used, even after it thaws out.

"Insulin is a protein, and freezing can affect the stability of the protein, thus making it not as effective if it were to freeze," said Jason Reed, Pharm.D., an expert in pharmacy benefit management and health information technology.

Similar impacts can occur in frozen vaccines, according to Svensson.

"Frozen vaccines can fail to create immunity in a patient for the disease for which the vaccine is given, [but] it is highly unlikely that, if used, such a frozen medication would produce a specific adverse effect," Svensson said.

Unfortunately, there is no way to visibly tell if a vial of insulin or other frozen drug has been damaged enough to render it ineffective.

"If a vial of medication like insulin is frozen, it should be replaced, and patients whose medication is unexpectedly frozen should contact their pharmacist to determine if it is safe to use," Svensson advised.


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"As pharmacies see more of these specialty companies that do mail order services or insurance companies that are moving to the mail-order practice model, it means large networks of the supply chain are moving these medications not just from manufacturers to a warehouse or to pharmacies for distribution, but back out to the patients," Pilz said. "So, it increases the amount of time that medication is exposed to some of those temperature extremes."

As there isn't a way that every mail order company or pharmacy service will package medications consistently in order to protect them, patients may not always see the same level of care with regards to ensuring that the product is maintained at an ideal temperature for storage, depending on which company is managing a patient's prescription, according to Pilz.

"Usually, we tell patients that if anything looks damaged or it doesn't seem like it was protected well, or maybe they were gone on vacation and they come back and find that it was outside for an extended period of time, definitely reach out to the pharmacist and see if there is a problem with using that medication, especially during those cold periods," he said.

Pilz recommended that if patients know that a package of medication is on its way, make sure that it is brought indoors or to a safe temperature as soon as possible.

For more safety and preparedness tips, visit AccuWeather.com/Ready.

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