Formulations
Drugs may be made into:
Capsules: These are powder loaded into individual capsules.
Loose powder: Allows you to measure a dosage by a convenient measure like a teaspoon. True shelf life of loose powders that are opened once or twice a day is unknown.
Liquids: Depends upon whether it's water- or oil-based. Be sure you ask.
Flavored chewable treats: These are a complete unknown in terms of how well the medication is absorbed.
Bottom Line
One reason compounded drugs are so inexpensive is that the pharmacies do not have to jump through the same quality-control hoops as drug manufacturers do. If you need or want to use a compounded product, start by asking if the pharmacy has an independent analysis on their finished product, and if they have conducted shelf-life studies. Most won't, but it never hurts to ask, and it clearly sends the message that you know how to ask the hard questions.
Don't rely on statements like "We've been making this for 20 years" or "Thousands of vets use our products." Get the most stable form of the drug available, preferably capsules, and ask about ideal storage conditions.
Finally, if your horse doesn't respond to the product as he should, switch to a more stable formulation or another pharmacy before giving up on the drug your vet recommended.
