With temperatures in San Diego County expected to soar between 90 and 115 degrees starting Wednesday, pharmacists are raising red flags about the safety of mail-order medications.
Millions of people across the country rely on mail delivery for prescriptions. While pharmacies like CVS said they use weather-adaptive packaging to keep medications safe during transit, drugs left in hot trucks or sitting on doorsteps can be exposed to extreme heat posing serious risks.
“Many of the injectables are just very small proteins that can be completely inactivated by high temperatures,” said Candis Morello, a professor at UC San Diego’s Skaggs School of Pharmacy.
Common medications like insulin, EpiPens, and inhalers are particularly vulnerable, she said.
“While mail-order medications are very convenient, we really need to help make people aware that these high temperatures can destroy the active ingredients in several of these injectable agents, or in inhaled agents as well,” Morello said.
Heat-damaged medication may look normal, but signs like reduced effectiveness, color changes, or unusual texture can signal it’s no longer safe to use.
Even with insulated packaging, Morello warned that heat damage isn’t always obvious, until the medication stops working.
“They might stay outside for 12 or 18 hours, and then if the patient uses the insulin, if it's not effective, the glucoses will just rise. That’s when I get a call: ‘My insulin is not working,’” she said.
In some cases, she said the consequences have sent patients to the emergency room.
Inland areas of San Diego County where summer temperatures often climb above 100 degrees are especially high-risk, Morello said. Vulnerable patients include the elderly, people who live alone and those who are immobile.
She recommends arranging for someone to pick up the medication immediately upon delivery and storing it in the refrigerator right away.
“If you’re unsure how to store your medication, talk to your pharmacist,” she said.
The U.S. Postal Service does not offer refrigerated delivery, according to spokesperson John Hyatt. Cold-sensitive prescriptions can be sent with insulated packaging, but that’s done at the sender’s own risk, he said.
