Medicating your horse seems simple. You get the drug and then administer it as prescribed. While your veterinarian will definitely give you the proper dosages, he or she may assume you know the most appropriate times/ways to administer the drugs.
Unfortunately, the best way to give certain medications isn’t always apparent or listed on the bottle label. In fact, giving it at a certain time in your horse’s feeding schedule can actually impact how well the drug does or doesn’t work.
Remember that a simple “stomach upset” isn’t always easy to detect in a horse. Belching or hiccups may occur in some horses soon after giving an upsetting medication on an empty stomach, but a subdued/mildly distracted or depressed attitude is the most common sign. The horse may have a decreased appetite or eat abnormally slow and/or have more intestinal gas.
We’ve listed major categories of drugs and advice on how to best give them. If you’re not sure what category the drug you’re giving falls into, ask your veterinarian.
ANTIHISTAMINES: These work best if given on an empty stomach, such as a half hour before feeding grain or hay in the morning.
NSAIDS (e.g. bute, flunixin, aspirin): Best to give with a grain or beet pulp meal to avoid direct irritation to mouth, esophagus and stomach. Withhold hay for several hours before and 30 minutes after giving bute, as bute can bind to the hay.
CORTICOSTEROIDS: Give with a meal to decrease stomach irritation.BRONCHODILATORS: Fat increases the absorption of these drugs. The likelihood of side effects like trembling, high pulse and excitement that occur in other species may occur with horses, too.
THYROID SUPPLEMENTATION: Soy and mineral supplements can interfere with absorption. Avoid high-calcium foods like alfalfa or beet pulp. Remember that many commercial grain mixes are highly mineral-fortified. Antacid powders or liquids are also usually high-calcium.
SULFA ANTIBIOTICS: Better absorption occurs if they’re given on an empty stomach. However, these drugs can cause stomach upset. If distress is noted when giving on an empty stomach, give the drug with food.
DOXYCYCLINE: Like sulfa, it’s best on an empty stomach unless stomach upset occurs. If given with food, avoid same foods and supplements as for thyroid medication.
ANTIFUNGALS (Griseofulvin, ketoconazole): Do not give with antacids, supplements containing calcium or iron, or high-calcium foods. Fat may increase absorption.
PROGESTERONE (Regumate): Can cause stomach upset, so it’s best to give this drug with food.