Any Pharmacists or Chemists able to answer a question? Re: Reformulating human medicine for cat

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Posted 4/17/2014 by Pea-T-A-Mom in NSBR Board

Scrapmaven is stalkin my Kitteh!

PeaNut 159,334
July 2004
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Posted: 4/17/2014 9:42:55 PM
Our vet prescribed Gabapentin for our cat, to ease pain from arthritis in her hips.

This is a medicine formulated for humans, so she called the Rx into a local pharmacy to Reformulate it into a dosage suitable for a cat.

It is a suspension (I guess the human dosage is powder in a capsule, so they open these capsules and mix the powder with water). 40 mg/ml suspension.

My husband was appalled at the price I paid for a 30 day supply ($41, for two doses a day), when he looked up the drug and claims that buying that much of the drug itself would cost around $1.

So he wanted me to call the vet, and ask for the Rx to be filled by the capsule, and have us mix the suspension.

My questions are many.

First, can a vet call in a Rx for a human dose medicine? Second, can a pharmacy dispense a medication in concentrated form that requires the patient (or patient's owner) to suspend the drug? Third, are we truly being charged a 4000% markup for this medicine?



PeaNut 197,496
March 2005
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Posted: 4/17/2014 10:01:28 PM
I would imagine you can ask the vet to specify that you get a capsule if you want. Unless the lowest dose capsule would be too much for your cat. I just filled a script for my dog for Prozac, and the vet wrote it for a dosage that it doesn't actually come in, so the pharmacist and I had a conversation about how we were going to get it filled.

And yes, I would believe the cost. But you have to remember that you're not using insurance to pay for it and if your vet carried it, it would probably cost more. That's the whole reason I got the Prozac from CVS and not the vet.


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PeaNut 167,693
September 2004
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Posted: 4/17/2014 10:11:22 PM
I don't think it's as simple as your husband thinks it is. Going by walgreens' website, the smallest capsule dose is 100mg. How are you going to measure out the right doseage from that to make the suspension?

There's also probably some rule about non-pharmacists not being allowed to adulterate prescriptions medication.


Harley Riding Pea

PeaNut 10,051
January 2001
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Posted: 4/17/2014 10:18:35 PM
I jake this med. The capsuls are impossible to get apart, I just tried it. Also, it's a powder in the generic I take, not the tiny balls of medicine. You'd have to have an extreamly accurate scale to mix it yourself.

Too little and my whole body aches for days. Too much and I have issues with balance, memory and function. Not a chance I'd want to take with my animal.

Scrapmaven is stalkin my Kitteh!

PeaNut 159,334
July 2004
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Posted: 4/17/2014 10:36:38 PM

Not a chance I'd want to take with my animal


I gave him our vets name and phone number to call tomorrow. Hopefully hearing the reasoning behind getting it from someone qualified to mix it will sound better coming from a medical professional than from me.


Donna in GA
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PeaNut 60,695
January 2003
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Posted: 4/17/2014 10:58:49 PM
I am not a phamacist, but I am a chemistry major. I would think the suspension is more than just the medicine in water.


PeaNut 177,931
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Posted: 4/17/2014 11:04:10 PM
Also, you are not just paying for the drug. You are paying for the pharmacist's time, knowledge and expertise. And believe me there is a lot more time that goes into this than your husband probably realizes. He would need a pharmaceutical scale that has been tested by your state's weights and measure division to ensure the measurement is accurate, as well as a knowledge of aliquot dosing so that the amount needed for the dose is properly calculated.

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PeaNut 111,502
October 2003
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Posted: 4/17/2014 11:16:02 PM
I assume you are in the USA?

In the feline cancer group I am in, many people from the USA use specialist vet pharmacies and one that gets mentioned a bit as having some drugs at better prices is Diamondback
They have a "get a quote" page that I've linked, so you could do that and find out if it is cheaper than what you paid at your pharmacy.
Mostly the drugs I've heard about are chemotherapy drugs, but probably still worthwhile finding out if their prices are cheaper.

The other one is Roadrunner

Some veterinary compounding pharmacies offer paste which can be rubbed into the ears...I wouldn't recommend that option as there is no sufficient evidence that many of those drugs are absorbed transdermally - go with a liquid or a pill or capsule.


PeaNut 441,182
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Posted: 4/17/2014 11:18:16 PM
I work with people who develop formulations for marketed drugs for animals and humans. I've also done the testing of drugs that are made for clinical trials.

First, I checked the cost of the capsules at Costco. For a 30 day supply for human doses, it's closer to $10.

Most any drug that you buy at a pharmacy will have lots of "inactive" ingredients. You can have much less than a cooking 'pinch' of the drug itself in a capsule. The inactive ingredients vary. They are used to improve the ability of the drug to dissolve in your body, improve stability, improve the ability to make the drug, etc. Your DH probably found a site that sells the unformulated drug, which are never available for purchase by consumers. Since this particular drug is generic, it's highly likely that what he found is made in India without concern about the safety and quality of their product.

Taking a human medicine and formulating it for cats isn't easy. For a dog, it's entirely possible to give them capsules if they're covered in something tasty. Cats, not so much. Very picky, hard to catch and keep still while dosing, etc.

The pharmacist will have to do a number of calculations to determine the correct concentration based upon your cat's weight and accounting for how much active drug is in a capsule. Since you're getting a 30 day supply, the pharmacist will need to add some ingredients to ensure that the suspension will be stable, not grow mold, etc. If it is formulated to stay as a suspension for the full 30 days, s/he will need to add other ingredients to keep the drug in suspension. The other option is to have you shake before dosing your cat. Oh, and flavors will be added to counteract the extreme bitterness of most medications.

Formulating medications requires special sterile water to prevent contamination that would occur with tap water. There is specialized equipment to do all the measuring and mixing that a standard pharmacy wouldn't have. And the standards for cleanliness of the lab area are very high, which adds to the cost. Compounding pharmacists have additional training and certification beyond a typical pharmacist.

So, no $40 is not at all unreasonable for a 30 day supply. It's a highly specialized task that you could not safely replicate at home.

Good luck dosing your cat. That's the hardest part!


PeaNut 421,228
April 2009
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Posted: 4/17/2014 11:32:11 PM
If the vet prescribed 40 mg/ml, and you can get 100mg capsules, you could technically open 2 capsules (200 mg) and mix with 5 ml of water to get the same 40 mg/ ml strength. You would want to find out if it's ok to store it like that, how long it will keep, if it needs to be refrigerated, etc.

If the vet says thats ok, you could probably mix your homemade suspension with a small amount wet cat food.


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PeaNut 463,630
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Posted: 4/17/2014 11:47:38 PM
If the cost is a problem (as the caretaker to a 13 year old dog and a nearly 16 year old cat, I get that!) talk to the vet about options. It may be totally possible to buy human dosed capsules, open them and the mix it with...whatever is in a suspension. Obviously, I am not a vet or a chemist! I wouldn't do it on my own, my cat is 8 pounds and I'm always sure I will kill her giving her too much/not enough of something because at those small sizes, it makes a big difference. But any vet worth their salt will try to find options for you.


PeaNut 558,349
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Posted: 4/18/2014 1:42:31 AM
My vet prescribed Metacam (Mobic) for my dog's arthritis & he started on the liquid (vet-grade). He told me that he could write a prescription for the dog to get the tablets (the same medicine take), but it would be very risky to try to get the correct dosage. Louis weighs 40 lbs, so I would think it would be too risky to try to adjust the meds for a cat.

I shopped around & found the best price at Vet was charging $55 for a monthly supply & now I pay $40/month & that includes shipping. I would think they would have the Gabapentin-you might want to check it out.


PeaNut 263,868
June 2006
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Posted: 4/18/2014 6:45:31 AM
I've not got experience compounding meds for pets, but I am a pharmacist. Just another vote that you're not getting a bad deal for $40/month. I'm not sure where your husband was getting that price quote, but it was likely the wholesale price of the (powdered) active ingredient. As previously mentioned, that doesn't take into account other ingredients, time, skill, and supplies.

Ancient Ancestor of Pea

PeaNut 75,215
March 2003
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Posted: 4/18/2014 6:45:32 AM
I wouldn't risk it -- like ip2oftn said, there are a lot of variables that go into something like that. It's not just breaking a pill in half.

I have prozac formulated into kitty treats for my cat (she's tiny and I can't break the smallest dose accurately.) It costs about $90 for a 90-day supply of one dose per day. I'm thrilled to pay it -- less expensive than cat pee on every soft surface in my house, LOL!

Having worked peripherally on pharmaceutical manufacturing equipment, I say there's a lot more to it than you think.


PeaNut 229,470
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Posted: 4/18/2014 7:21:41 AM
I'd be really reluctant to try mixing any medicine myself because my pet means the world to me and I wouldn't want to do anything that might potentially harm it. I hope you can convince your husband that it's worth it to have a professional do it. My cat was on Cosequin, which is glucosamine and chondroitin, and that seemed to help her.


PeaNut 106,441
September 2003
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Posted: 4/18/2014 7:54:20 PM
Hope kitty feels better.
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