Drug Expiration Dates: For Real or Just a Suggestion?

By L'illete Vasquez, Reprinted from LANA, Vol. 106, Spring 2010

This question comes up repeatedly, so I asked LANA's representing veterinarian for the Morris Animal Fund. Dr. Tim Thompson of Town & Country Veterinary Clinic (TCVC) in Platteville, CO (tcvc.net) for his thoughts on the validity of drug expiration dates.

"It is difficult to make blanket statements regarding expirations and potency of the products we use, but I will try:

• Hormones and metabolic preps: i.e., HcG, lutalyse, insulin: Should be considered extremely questionable past the expiration date. Do not use.
• Antibiotics: As long as they have not been subjected to abuses in storage—i.e., freezing or extreme heat—are probably close to expected efficacy as long as there is no color change or precipitate. I have found many producers in the past using these products with adequate results. Always check, though, if unexpected results occur: check expiration dates again.
• Other injectables: i.e., Banamine, lasix, etc.: Should follow the same guidelines; however, it is difficult to know how much the product has degraded once expired.
• Vaccines: Should not be used past expiration. Antigen degradation in the case of killed or toxin-derived vaccines and bacterins starts soon after manufacturing; and sometime after expiration, they will stop adequate stimulation of the immune system. Live vaccines and bacterins are even more liable.
• Powders and pills: Can be variable due to oxidation, heat, and humidity. If storage is good, they could potentially last well past expiration. Take it case by case, and watch results closely.

"Even if a product is well within its expiration, it is important to remember that it can still be bad. This is especially true of vaccines. If in doubt, or if you get unexpected results, change products."

LANA Editor's Note: Dr. Thompson makes no recommendations. If in doubt, or if you have any questions, always check with your vet!