Medication Safety

Handle and store your horse's medications safely

by Dave Sauter, DVM

Previous articles have discussed how to administer medications to horses, whether injectable, oral or topical. This month, I'd like to focus on proper handling of medications to ensure the stability, safety and effectiveness of the products.

Temperature

Many medications need to be stored within specific temperature ranges. Temperatures outside these ranges can alter the chemical nature and stability of the components. For example, vaccines are very sensitive to storage temperatures. Freezing can cause some vaccines to lose their effectiveness and become much more reactive--in other words, much more likely to cause heat, swelling and pain at the injection site.

Another example is penicillin. The most common type of penicillin used in horses is Procaine Penicillin G, which is supposed to be refrigerated but not frozen. There are different types of penicillin injection reactions, and all of them are pretty scary. One of the reactions (disorientation, fear response, seizure and collapse) is thought to be related to the procaine. The procaine in Procaine Penicillin G is bound to another chemical. Storage at room temperature has been shown to result in more release of the procaine from this other chemical and to increase the chance of this reaction.

To keep medications stable, safe and effective until their expiration dates, follow label recommendations for storage temperatures. If refrigeration is required, do not store medications in the door of the fridge, where temperatures fluctuate more; keep them near the center.

Sunlight

Many medications are sensitive to sunlight. For example, sunlight inactivates ReguMate. Medications in dark-colored bottles often are light sensitive (e.g., Acepromazine). Direct sunlight can be particularly damaging to vaccines, resulting in less immunological effect (which is the goal of vaccination in the first place) and greater injection site reaction (which we all strive to prevent).

Transport

It is important to maintain proper storage conditions during the transport of medications. If you have a long drive from the veterinary clinic to the farm, putting medications on the dash where heat and sunlight can damage them is not a good plan. Use a small cooler to keep your refrigerated products cool, but do not place products like vaccines directly onto an ice block. Similar precautions should be taken when necessary to protect products from direct sunlight and extreme temperatures when they are taken out of storage for use in the horse.

Cleanliness

This is particularly critical with injectable products. Products such as Procaine Penicillin G, Naxcel or Banamine are in multi-dose vials. Each time the needle enters the bottle there is the potential for contamination. Injection of a contaminated product into the horse can result in cellulitis, deep abscesses, and other serious complications like tetanus. Store these products in a clean environment. Clean the surface of the rubber injection cap, if it is dirty, with gauze soaked in 70% isopropyl alcohol (rubbing alcohol) before inserting the needle. Always use a new needle and keep the cap on it. Never touch the needle or allow it to touch anything but the medicine and the horse it is intended for.

Dosage

Follow the label directions as closely as possible.

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Make sure to prepare and deliver the correct amount at the proper interval. Always double and triple check that the prescribed amount of medication is prepared. For instance, it is easy to overdose an oral medication in a multidose cartridge, such as Bute, if the dial is not set properly.

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Do what is safe and necessary to administer the medication to the horse. If the medication ends up on the wall or the floor instead of in the horse, then the horse is not going to maintain therapeutic levels in its body.

· Follow the instructions on dosing interval. Shortening the interval can result in toxicity. The medication will drop below therapeutic levels if the interval is increased. This is especially problematic with antibiotics because it will cause drug resistance. Once a day means every 24 hours, twice a day every 12 hours, three times a day every 8 hours, four times a day every 6 hours, etc.

Personal Safety

Many of the medications we use in horses are powerful drugs that can affect us. I am still amazed when I give less than one cc of sedative to a one ton draft horse and see the powerful effect that tiny little bit has on such a huge animal. During the preparation or administration of medication, small amounts can get on our hands. Rubbing one’s eyes or mouth can inadvertently result in absorption of these drugs into our own bodies. Ventipulmin syrup can cause your heart to race. Atropine eye ointment can cause your pupils to dilate. ReguMate can absorb through the skin and affect the female reproductive system (and probably the male, also). Take precautions with all medications. Use gloves when so instructed and avoid rubbing your eyes or touching your face until you have washed your hands. Always wash your hands after handling any medications.

Proper Disposal

Children and other animals, often dogs, are at the highest risk of getting into contact with used oral medication cartridges, tubes of topical medications, used vials, etc. Children and pets can be very curious and very fast. One example I recall is that of a border collie that licked the end of a dewormer cartridge that had been dropped on the floor after use. There was a little paste on the end, enough to cause neurotoxicity. Fortunately, the dog survived. The owner still lets the dog follow him around the barn, but he doesn’t throw used cartridges on the floor anymore.

Needles deserve special mention. The EPA estimates that eight million people use more than three billion sharps (needles, syringes and lancets) per year in the United States. Leftover needles not only carry the risk of pain from accidental puncture, but also the risk of disease. In many counties and cities, it is against the law to dispose of used needles in garbage cans or recycling bins. Check with your county Department of Health for rules and guidelines for the proper disposal of used needles in your area. Here are some websites with more useful information:

· Coalition for Safety Community Needle Disposal - www.safeneedledisposal.org

· Centers for Disease Control - www.cdc.gov/needledisposal

· Whatcom County Health Department - www.co.whatcom.wa.us/health

· www.sharpsdisposal.com

· www.stericycle.com/mailback.html