Background
Medicines are usually stored at room temperature between 15 to 25 °C (sometimes up to 30 °C). However, for relatively many drugs, storage in the refrigerator at a temperature between 2 to 8 °C is mandatory. Why? At a low temperature, the molecular movement and reactivity of the compounds is reduced, germ growth is inhibited, stability increases and shelf life is extended. At a higher temperature, the active ingredients can be degraded or inactivated and the effectiveness is reduced. Not only the active ingredients, but also the excipients or dosage forms can be temperature sensitive. A storage temperature between 8 and 15 °C is rarely specified, i.e. approximately the cellar temperature. It is referred to as “cool” or “cold” in the pharmacopoeia. However, this prescription can pose problems for professionals and patients, as the refrigerator is too cold and the room temperature is too warm. For such medicines, the optimal storage temperature should be determined in consultation with the manufacturer. The terms “frozen,” “refrigerator,” “cool” (“cold“), and “room temperature” are defined by the pharmacopoeia.
Cold Chain
Temperature plays an important role throughout the entire journey from the manufacturer to the patient (cold chain): manufacturer storage rooms transport to wholesaler storage transport by van to pharmacy/doctor’s office dispensing transport in car storage in the home
Do not freeze!
As a rule, medicines requiring refrigeration must not be frozen, because this can destroy them. The drug information leaflet provides information about possible exceptions. Only a few medications are stored frozen, for example some blood products.
Storage with patients
After dispensing to patients, some – but not all – drugs requiring refrigeration can be stored at room temperature for a defined period of time. If used immediately, no further refrigeration is then necessary. However, a supply must also be placed in the refrigerator at the patient’s home. It is mandatory to draw the attention of the customers to the correct storage when dispensing the medicines. A clearly visible label with the relevant information should also be stuck on the package (including temperature information). The temperature distribution inside household refrigerators varies. In general, storage in the middle is advisable. In case of doubt, the instruction manual should be consulted or a thermometer should be used. In the door and vegetable compartments, the temperature is usually too high. Medicines should not be stored in the freezer compartment or near it! It is also important to keep the temperature on the road and when traveling. In summer, high temperatures are quickly reached in cars. For critical medications, a cooler bag or cooler box with cooling elements can be used. However, these containers must be suitable for medications and guarantee the prescribed temperatures (e.g. Cool*Safe)! The preparations must not come into direct contact with the cooling elements. The medication or the cooling elements should be insulated with plastic, cardboard or paper, for example, to protect the preparation from moisture.
Temperature deviations
If a medication has not been stored properly, patients should contact a professional (pharmacy, doctor’s office) with the complete information. This person must contact the pharmaceutical company if necessary. Some hospitals and pharmacies have checklists of actions to take.
Examples
The following list includes medications that are stored in the refrigerator before and sometimes after dispensing:
- Antibiotic suspensions, after preparation.
- Biologics such as proteins, blood clotting factors, enzymes, antibodies and receptors.
- Cannabis oral spray (Sativex).
- Glucagon syringe (GlucaGen), before delivery.
- Vaccines, e.g., influenza, TBE, typhoid, until shortly before injection.
- Injection and infusion preparations, e.g. Epoetine.
- Incretin mimetics such as liraglutide (Victoza).
- Insulins
- Latanoprost eye drops (generic), at room temperature: xalatan, monoprost.
- Malathion shampoo (Prioderm).
- Tafluprost eye drops (Saflutan)
- Monoclonal antibodies
- Probiotics, e.g. Gynoflor vaginal tablets.
- Contraceptive ring (NuvaRing)
- Some cytostatics and other anticancer drugs, e.g., trametinib (Mekinist)
Some drugs used to need to be stored in a cool place and can now be stored at room temperature. These include rotigotine patches (Neupro) and original latanoprost eye drops (Xalatan).