Pharmaceutical companies share a duty to ensure that their drugs are kept in an environment that maintains their efficacy. Although USP sets standards for the proper storage and distribution of medicines, many state boards of pharmacy follow these guidelines erratically. Since many drugs become unstable at high temperatures, keeping them within the proper “cool” or “cold” range is essential.
“Cold” Has No Absolute Value
Labels often state that medications should be stored in a “cold” or “cool” place; however, these terms are subject to interpretation. USP defines “cool” as any temperature between 8°C and 15°C. Consequently, USP defines “cold” as any temperature between 2°C and 8°C.
The majority of state boards of pharmacy comply with the USP guidelines, but not all. Boards that don’t explicitly provide these temperature range guidelines typically follow the medical label’s requirements for storing drugs. Yet these requirements are based on the manufacturer’s own operating procedures, which are not standardized.
Drug Stability at Room Temperature
Like “cold” and “cool,” “room temperature” is also subject to interpretation. When a medication is labeled for refrigeration, the duration it can remain stable at room temperature is highly variable—from months to only hours. Thus, continually monitoring refrigerator temperatures to track drug temperatures is essential across the cold chain.
Drug Stability at High Temperatures
According to a study in the Journal of the Royal Society of Medicine, exposing medicines to high temperatures in storage or in transit can reduce their efficacy. For example, the capsules of certain brands of antibiotic degraded more rapidly in hot conditions, which caused “serious fluctuations” in absorption. The study concludes that manufacturers need to offer more drug stability data in relation to temperature and should consider arrangements for cooling.
Using Automatic Devices to Monitor Temperature
Although not required, continuous monitoring systems for temperature are more reliable than manual systems. In fact, an alarm system is highly recommended—one that indicates when temperature falls below or exceeds the desired range. CDC recommends that systems using an automatic data logger should download the temperature recordings at least once per week, always at the same time.
Better Safe Than Sorry
Many drugs can be used after temperature stress of limited duration. Nevertheless, The Journal of Travel Medicine recommends that they are replaced at least once per year or after exposure to extreme heat (in most cases temperatures exceeding 25°C). Otherwise, if not monitored carefully, a drug’s pharmacokinetic properties at high temperatures will differ adversely from those at normal administration.