Why is Pharmacy Temperature Monitoring so Important?

If medications and vaccines are stored at the wrong temperature, several things can go wrong – rendering them less effective than intended or even chemically altered, causing inadvertent patient harm.  Because of this risk, pharmacy regulations are strict about how medications are to be manufactured, transported, and stored before they reach the patient.  

The ideal pharmacy room temperature range for most medications is between 68° and 77° Fahrenheit, however different medications and vaccines have different temperature requirements which must be followed continuously. Pharmaceutical manufacturers are held to strict quality control standards for manufacturing and delivering medicinal products under the right storage and transport conditions.  If the temperature ever deviates from the specified range, this is called a temperature excursion. 

How a temperature excursion is handled depends upon whether the temperature was above or below the prescribed range, and the manufacturer’s instructions. 

Products that are sensitive to high temperatures can be altered in the following ways:

• The active ingredient content is decreased because the components are degraded via oxidation, hydrolyzation, or other methods. Some of these ingredients can even become toxic. The longer the time and the higher the temperature of exposure to the out-of-range temperature, usually the higher the percentage of product is degraded.
• Properties of the specific formula can be altered as well.  For example, the color of the medication, the rate at which it is dissolved, or separation of emulsions.  

Products that are sensitive to low temperatures can be damaged by losing therapeutic properties, usually after a freeze/thaw cycle.  

• This changes the active ingredients’ physical structures permanently, rendering the medication ineffective.
• Some products lose physical usability after a freeze/thaw cycle. Examples would be creams or biologicals that separate and are no longer the same consistency. 

The manufacturer must adhere to and document temperature controls during the handling of bulk products, packed products and shipped products until they are in their final storage location, such as a pharmacy.  From there, the pharmacy must accept the responsibility for proper pharmacy room temperature range and document accordingly, according to regulations and individual product instructions. 

Refrigeration and the Cold Chain

Many vaccines and biologics that are distributed from a pharmacy are dependent on what is called the cold chain. A cold chain is a temperature-controlled supply chain with specific monitoring and procedures in place. It begins with the cold storage at the manufacturer and ends with the correct pharmacy room temperature range before distributing it to the patient. 

Maintenance of the cold chain is a big responsibility, especially in the face of events like the COVID-19 pandemic.  COVID vaccines are susceptible to heat and rely on an unbroken cold chain to maintain their efficacy. According to the CDC, in its Vaccine Storage and Handling Toolkit, an effective cold chain relies on three elements:

• A well-trained staff
• Reliable storage and temperature monitoring equipment
• Accurate product inventory management

It is important that vigilance is used throughout the entire life of the product. Maintaining precise control over the temperature storage conditions of pharmaceuticals has become one of the primary roles of the pharmacy. When the cold chain is broken, this can result in lowered effectiveness of the product – meaning extra doses for patients, increased costs for providers, and damage to public perception of the vaccine, medication, or manufacturing company. 

It is not possible to tell by visual inspection if products have been stored in appropriate conditions. For example, vaccines that have been inactivated by freezing temperatures may no longer appear frozen.  This gives no indication of what has happened to the product’s molecular structure, causing reduced or lost potency. 

Requirements for Storage and Temperature Monitoring Equipment

Purpose-built Units

Pharmacies should follow best practices and use only pharmaceutical-grade refrigeration units.  Dorm-size or household-type refrigerators are not as reliable and may have significant temperature fluctuations in different areas of the refrigerator. Purpose-built units are designed specifically for the storage of biologics, including vaccines. These units have the following features:

• Microprocessor-based temperature controls with a digital sensor. 
• Fan-forced air circulation promotes uniform temperatures and fast recovery from an out-of-range temperature. 

Storage Unit Placement

It is important to maintain good air circulation around the outside of the storage unit, and the room itself must be well-ventilated. Be sure to leave space between the unit, the ceiling, and any walls, with nothing blocking the cover of the motor compartment. 

The unit should be level and firmly placed, with the unit door opening and closing smoothly. If gaps exist in the door, or it does not close smoothly, there is a risk of maintaining the appropriate internal temperature. Vaccine storage units work best when placed in an area with standard indoor room temperature (between 68° and 77° F). Another important point to remember is to hold off on using a brand new or newly repaired refrigeration unit until the temperature has been stabilized.  This may take at least a couple of days.  During this time, the minimum and maximum temperatures should be recorded within range for two consecutive days. 

Temperature Monitoring Devices (TMD)

According to CDC guidelines, every vaccine storage unit must have a TMD. TMDs provide an accurate, around-the-clock temperature history that is critical for protecting vaccines. The CDC further recommends a particular type of TMD called a digital data logger (DDL). DDLs provide the most accurate storage unit temperature information, including detailed information about temperature excursions. Unlike a simple minimum/maximum thermometer, a DDL records times at each temperature and stores the data for easy retrieval. 

The most accurate way for DDLs to measure vaccine temperatures is with a buffered temperature probe. Temperatures measured by a buffered probe have been found to match vaccine temperatures more closely than standard thermometers, which tend to better reflect the air temperature. 

Data from a DDL can either be downloaded to a computer or retrieved from a website.  Reviewing DDL data is critical for vaccine life and viability. The data from a DDL should be kept for a minimum of three years so that it can be analyzed for long-term trends or recurring problems. Be aware that some state regulations require a longer period of data storage. 

A DDL must be used for each vaccine storage unit and each transport unit. DLLs should have the following features:

• A buffered probe
• Alarm for out-of-range temperatures
• Low-battery indicator
• Current, minimum, and maximum temperature displays
• Recommended uncertainty of only +/- 1°F. 
• Logging intervals can be programmed by the user to measure and record temperatures at least every 30 minutes. 
• Each DDL should have a current and valid Certificate of Calibration Testing. 

Calibration testing should be done every two to three years, as TMDs can experience “drift” or slight changes in accuracy over time. Calibration testing ensures that each TMD remains in compliance and conforms to nationally accepted standards. 

Pharmacy Rooms and Storage Setups

The environment in which refrigeration and freezer equipment resides is just as important as the equipment itself when it comes to medication and vaccine safety. The room(s) should have a consistent and reliable power supply. If power disruption occurs, this can result in the destruction of the entire medication or vaccine supply. 

According to the CDC, the following precautions should always be taken to protect the power supply:

• Plug in only ONE storage unit per electrical outlet to avoid creating a fire hazard or tripping a breaker. 
• Use a safety lock type plug, or an outlet cover to prevent the unit from being inadvertently unplugged. 
• Post signage that says “do not unplug” at outlets and on storage units to alert staff and other workers.
• Label fuses and circuit breakers to alert people not to turn off power to that circuit. 
• Do not use built-in circuit switches (the type with a reset button), outlets that can be activated by a wall switch, or multi-outlet power strips. 
  
  

Technological Advances in Temperature Monitoring

Advances in technology have led to the widespread use of cloud-based data storage in the healthcare industry.  This system is a much more reliable system of storage than the physical storage of data on-site.  Cloud data is stored off-site and can be accessed by multiple authorized users at a time, from any location. Environmental monitoring systems that use cloud data storage put to use the advantages of reliable, efficient, and scalable systems. 

Maintaining tight control over temperature requirements from the manufacturer to the end storage at the pharmacy is a complex process.  Selecting the right equipment for the job, placing it in the right environment, and then monitoring it correctly with the right data logger technology is key to patient safety and the efficacy of critical medications and vaccines.