Safe Storage of Medications

Posted by Nancy S. Loving, DVM on 06/09/2020

When faced with a horse emergency, it’s always a good idea to have a well-stocked first aid kit on hand. Yet, how many times have you gone to the tack room and reached for the cardboard box containing the supplies only to find dust accumulation on it? You can’t remember exactly how long ago it was last used. This might be a good time to slow down and think through carefully before using any of the contents in the box. There are a few important considerations to focus on about medication storage and shelf life to ensure that you do no harm and are able to achieve successful results.

Storage Strategies

Above all, aim for cleanliness. This can be accomplished by using a container that seals tightly so everything inside remains in pristine condition. Examples of useful containers are “tackle” boxes that seal well or a plastic container fitted with a snap-on lid. 

The next element to consider is temperature – most medications require room temperature storage unless otherwise specified on the bottle. Too much heat or cold may inactivate ingredients. While tempting to store medicines in your tack room, feed room or horse trailer, these areas tend to heat up in summer and freeze in winter. Preferable storage for liquids and pills is at a constant temperature. Some supplies, like elastic-backed bandaging materials, are pretty frustrating to unroll if the sticky has “melted” after being stored in too much warmth.

Thirdly, consider humidity. A damp, warm environment, such as found in your bathroom, has adverse effects on drug stability, thereby speeding up deterioration of many medicines. Storage in a sealed, impermeable container usually protects medications and supplies from changing humidity.

Fourthly, consider light. Products, such as vitamins, need to be stored in the dark to delay degradation. Ultraviolet-sensitive medications are often packaged in a lightproof container, but a dark place is ideal for storage. Also, metal can inactivate some powders or pills, so these are best stored in plastic or paper-lined containers.

Finally, think childproof! This is certainly not the least important consideration and it must be addressed. Wherever you store your first aid kit, be sure neither children nor small pets can access it. Put it in a locked cupboard or at least place it high up on an inaccessible shelf. Store syringes and needles in a location apart from bottles of liquid medications. Childproof caps are helpful to use on bottles with tablets or capsules. If medications or vaccines must be stored in the refrigerator, figure out a way to keep curious children from harm by accidental injection or ingestion.  

Drug Degradation

When liquid medications sit for a time, it’s not uncommon for sediment to form on the bottom of the bottle. In some cases, these particles contain essential active ingredients that are now no longer mixed in suspension. If shaking is able to return the liquid to an evenly mixed solution, it may be okay to use if still within its expiration date. If in doubt, it’s better to discard it and purchase new product.

Some drug preparations may experience chemical incompatibilities due to interaction with preservatives or solvents within the bottle that alter the pH or are sensitive to heat or cold. This can lead to premature precipitation of sediments or residue, color changes, or formation of gas. Despite no visible changes, such deterioration may cause the drug to be inactive. Similarly, an injectable drug may be absorbed into the plastic walls of a syringe if stored there for an extended time – then it is possible to administer an inadequate dose.

Considerations for Multi-Use Medications

Not all medications are used in entirety when a bottle is opened or punctured with a needle. Most injectable products are sterilized with heat or filtration to remove contaminating bacteria or foreign protein – sterility is compromised with the first needle puncture into the bottle. Keep bottles in a dust-proof container and also wipe the rubber stopper clean with antiseptic or alcohol prior to inserting a needle. Care must be taken with multi-use vials to avoid contamination of the contents – if there is any question about safety for future use, it is best to discard the medication. 

Topical salves that have been used previously, like wound or eye ointments, are often contaminated with dirt and hair; these present a health hazard if used again on your horse. Take care to use something like a clean tongue depressor when scooping out wound ointment or cream and then immediately and carefully seal the container’s lid. This enables you to use that product again, or to apply it to a superficial wound. 

Handling Vaccines 

To maintain efficacy of vaccines, it is critical that they are stored properly under refrigeration. If you plan to administer your own vaccinations to your horse, be sure to purchase vaccine products from a reputable source, such as your veterinarian. This ensures that the vaccine has been handled properly and kept under refrigeration during transfers from manufacturer to distributor to veterinarian, without loss of potency. In addition, you are also assured that vaccine isn’t outdated, but it’s always smart to check the expiration date on the vial or packaging. 

In contrast, there is no guarantee that vaccine purchased from a warehouse or wholesale outlet, feed store, or veterinary bulk supply outlet has been handled properly or that dating is current. Any mishap in handling or inadvertent administration of an outdated product could mean that your horse won’t receive adequate immune coverage from the vaccine. 

Once the vaccine is in your hands, it falls on you to continue to store it appropriately under refrigeration. If you aren’t able to administer it immediately to your horse upon removal from the refrigeration, then protect it in a cooler with ice packs for the few hours before you get to the barn. This prevents absent-minded mistakes like leaving the vaccine on your desk at work or on the dashboard of your truck in the sun. Be careful not to place the vaccine directly on ice packs where it might freeze. Both heat and excess cold will inactivate vaccine components. While this isn’t likely to be dangerous to your horse, compromised vaccine doesn’t give your horse protective antibodies against the disease(s) you’re trying to immunize against.

Lack of vaccine potency is not always obvious based on visual inspection of a vial or syringe. If there is any doubt as to whether or not vaccine has been handled properly under refrigeration, it is better to discard it and obtain a fresh supply. Proper disposal practices should be followed, such as giving it to your veterinarian to discard as medical waste along with used syringes and needles. 

Shelf Life vs. Expiration Date

Expiration Date

Check the expiration date of any product you are about to use in your first aid kit. An expiration date is what the drug manufacturer deems the longest period of time they can guarantee full potency and efficacy of that medication following manufacture. 

Expiration dates typically extend 2-5 years from the time of manufacture. In some cases, the intent is protective to the consumer – purchase of a new batch of a drug provides an up-dated product insert with current medical information that wouldn’t otherwise be communicated. For a drug company to maintain representative batches of medications in proper storage conditions for periodic testing of efficacy is an expensive undertaking; therefore, the tendency is to err on the conservative side when listing expiration dates. 

Shelf Life

The shelf life of some products may last beyond the listed expiration date, especially if stored in optimum conditions. The FDA’s U.S. Food and Drug Administration defines shelf-life: “Shelf-life generally means a product will retain approved specifications in the final packaged container, in stated storage conditions, when tested by validated methods.” 

Despite definite expiration dates, studies by the FDA in their Shelf Life Extension program (SLEP) evaluated the efficacy of expensive prescription drugs and found that shelf life persists beyond a manufacturer’s listed expiration. Duration varies greatly between lots and type of packaging. In general, the study revealed that many unopened products stored properly still retained effectiveness for 5-9 years following the expiration date. That doesn’t necessarily apply to medications in your horse’s first aid kit, but it is an interesting point of consideration. 

More importantly, caution should be used when administering antibiotics – many reasons prevail as to why you should only use antimicrobial drugs that are not expired. Loss of efficacy of an antibiotic may prove advantageous to microbes as they develop resistance to that drug or class of drug, rendering that antibiotic ineffective now and in future. This has significant public health ramifications for the human population as well as the animal industry. In addition, if an antibiotic loses its potency, then the infection you are trying to treat in your horse may not resolve successfully – this leads to prolonged illness or injury and increased costs of treatment. Use of out-dated antibiotics is not only counterproductive to horse health, but is also not economically practical. And, it becomes a public health concern as well, since many of the same antibiotics used in equine medicine are used for humans and bacterial resistance has life-threatening consequences.

With regards to any medication, follow all manufacturer recommendations and labeling for storage and use, and consult your veterinarian with any questions.

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