Medication Storage in the EMS Environment: Understanding the Science and Meeting the Standards

It’s the middle of winter, and you’ve been dispatched to a “possible heart attack” at a local assisted-living facility. As you and your partner drive toward the location, the ambulance heater barely keeps the cab warm, and you’re both shivering when you arrive on scene. As you walk into the building’s lobby, you’re shocked to see two things: Someone is actually doing CPR, and the victim appears to be relatively young—maybe 35 or 40 years old. A quick look reveals ventricular fibrillation, and you administer three defibrillations without response. Your partner intubates the patient, you start an IV and administer epinephrine, and—with assistance from a second unit—you continue through the entire ACLS algorithm, transporting the patient to the nearest emergency department. Unfortunately, the patient never regains a pulse.

It’s the middle of summer, and you’ve been dispatched to a “possible asthma attack” at a nearby playground. As you and your partner drive toward the park, the ambulance’s air conditioner can barely cool the cab, and you’re both sweating profusely before you even arrive on scene. Once there, you find a 15- year-old girl in severe respiratory distress. You apply oxygen and begin to administer breathing treatments, but she doesn’t get better. En route to the hospital, you start an IV and continue the nebulizers, but there’s still no response. At the emergency department, she is placed on continuous nebulizer therapy and begins to improve. She is eventually admitted to the hospital, but she does not require intubation and is discharged the next day.

Neither of these scenarios is particularly uncommon. Sometimes, prehospital interventions simply don’t work and, although that’s always disappointing, usually nobody thinks there’s anything more to it. But is there?

Medication Storage Standards

In the United States, standards for medicines are set by the United States Pharmacopeial Convention Inc. (USP), a nongovernment entity that establishes standards intended to ensure the quality of medicines and other healthcare technologies.1 The role of USP and its “National Formulary” (USP-NF) is recognized in federal law under the Federal Food, Drug and Cosmetic Act.2,3 Among other things, the USP-NF prescribes the packaging, storage and distribution of medications.

Most of the medications commonly used by EMS are intended for storage at “controlled room temperature.” The USP has the following very specific and technical definition for controlled room temperature:

“A temperature maintained thermostatically that encompasses the usual and customary working environment of 20°–25°C (68°–77°F); that results in a mean kinetic temperature calculated to be not more than 25°C; and that allows for excursions between 15°–30°C (59°–86°F) that are experienced in pharmacies, hospitals and warehouses. Provided the mean kinetic temperature remains in the allowed range, transient spikes up to 40°C are permitted, as long as they do not exceed 24 hours. Spikes above 40° may be permitted if the manufacturer so instructs. Articles may be labeled for storage at ‘controlled room temperature’ or at ‘up to 25°C,’ or other wording based on the same mean kinetic temperature. The mean kinetic temperature is a calculated value that may be used as an isothermal storage temperature that simulates the nonisothermal effects of storage temperature variations. (See also Stability under Pharmaceutical Dosage Forms .)”4

Table I lists some common EMS medications and the temperature-related storage directions on the package label (the package label may also address light and humidity, among other things). Clearly, the official definition for storage conditions is much more complex than what appears on a medication package. When a medication package says “store between 59°–86°F,” that really means “store at controlled room temperature.” When a medication package says, “store at 25°C,” that also means “store at controlled room temperature.” Further, medications are supposed to be stored in a manner that’s compliant with the entire definition of controlled room temperature, so simply measuring the range of temperatures at which medications are stored, or the maximum temperature, or even the average temperature doesn’t actually address whether medications are appropriately stored.