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Wednesday, November 21, 2012

Veterinary Pharmacy

Erin emailed me with this very timely question...

Anyhoo, the presenter discussed a concern by vets of pharmacists erroneously changing drugs or dosages based on their human knowledge. I have to say, this blindsided me. Amox 1gm BID x 14 days yields a double-take to nary a pharmacist, and it embarrasses me that a pharmacist would think, "oh, I'm sure Dr. Smith meant 500 mg BID x 10 days, I'll see fit to change it myself." I've been in the field of pharmacy and/or general healthcare for about a decade and have worked with more pharmacists than I can count. I've found them to be much more hesitant about dispensing for animals than even the oldest old lady with CKD, so his mention of this was surprising.

The point of this ramble was to see if you've ever had experience with this or known of someone who has. Similarly, is there a good resource for veterinary pharmacy? Any insight would be greatly appreciated, and I appreciate your time.

A few weeks ago when I was at a continuing education conference this very topic was the subject of an entire lecture.  Historically human pharmacies have not stocked anything related to animals, concentrating only on human medications.  At the same time veterinarians used their in-clinic pharmacy as a potential profit center, prefering to fill things in-house rather than write a prescription.  In the last few years we have seen a big shift in medicine dispensing.  Many large pharmacies offer common medications at a substantial discount or even free, something that a vet can't compete with.  We're also seeing a shift to some veterinary medications being carried in human pharmacies, such as Wal-Mart now stocking heartworm preventative.

There are certainly medications used in common with humans and animals, such as amoxicillin and cephalexin.  However, there are also plenty of drugs that are found only in veterinary medicine and don't have a human equivalent.  Sometimes we may use a human drug but at a much different dosage than for people.  Let's look at levothyroxine, a supplement for low thyroid levels.  In humans the highest dose you'll find is around 0.2mg, but in dogs that would only treat up to 20 pounds.  For larger dogs we will use 0.8 or 1.0mg which isn't even available for humans and many pharmacists would be astounded as these dosages.  I've also run into problems when clients have wanted me to write a prescription for amoxicillin plus clavulenic acid.  In veterinary medicine this is normally sold under the brand name Clavamox, and in humans it's commonly known as Augmentin.  The problem is that the ratio of amoxicillin to clavulnate is different in the veterinary and human compounds.  I usually have to work with a pharmacist to find something equivalent with what they cary, and it's usually no cheaper than what I can sell.  So in many cases it's not as simple as writing a prescription and having a client fill it.

Human pharmacists have been known to alter prescriptions, especially with pet medications.  The lecture I attended talked about a case where a pharmacist received a prescription for a certain kind of insulin, then recommended a different one that was cheaper and based on their knowledge of humans should have worked as well.  This was an absolutely wrong choice and resulted in severe hypoglycemia that caused the dog to have to be euthanized.  It was a very tragic example of how you cannot extrapolate knowledge of one species to another. 

Currently human pharmacists get little to no training in veterinary pharmacy.  In fact, there are only a few pharmacy schools that even offer a course in this field.  Pharmacists are highly trained in toxicology, medication, physiology, and how these drugs interact with each other and with their patient.  They are an essential part of medical care and can be relied on to discuss the ins-and-outs of medications with expertese.  But they don't know much about animal physiology, which can be significantly different from humans.  Even between dogs and cats there are significant differences, where medications safe to one may be toxic to another.

Let me be firm in saying that pharmacists changing prescriptions are the exception and not the rule.  In fact, to my knowledge it is illegal for a pharmacist to change a medication or instructions without first consulting with the prescribing doctor.  So these cases have happened but the pharmacist doing so is breaking laws and their ethical duty, something that the large majority of the profession is certainly not doing.  But there are going to be bad apples in any job.

This is a great area for pharmacists and veterinarians to work together.  I've had wonderful experiences with pharmacists where we learn from each other and both respect the other's knowledge.  I also think that pharmacy schools need to see this growing trend in pet medications getting filled outside of the veterinary office and include appropriate courses in the training.  If nothing else pharmacists should be aware that there are significant differences among species, and should be even more cautious with veterinary prescriptions than with human ones.

Great question, Erin!

4 comments:

  1. Excellent info, Chris! Thanks.

    I'm not in a medical field, but of course I expect there to be (potentially vast) differences between species. Some of that was very surprising, though. For instance, I never would have guessed that, for some meds, an animal may need a significantly higher dosage than a much larger human!

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  2. Temple University's Pharmacy school has an elective course where the students spend 6 weeks at the University of Pennsylvania's Veterinary Hospital learning precisely these things. Each and every one of the students I've dealt with on that course has been amazed by the differences, and one has since gone on to graduate and may be coming back to work as a pharmacist in the vet school itself.

    I think other schools should offer such courses!

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  3. Orli, that's great! That kind of course is exactly what we need pharmacists to take and be informed about. I'm perfectly okay with writing prescriptions for my clients and having them filled elsewhere. However, I will feel more comfortable when more pharmacists are trained in the veterinary applications of drugs.

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