Phenylpropanolamine and Your Dog

Prion

There is a veterinary phenylpropanolamine product available called Proin (Rx), for the treatment of incontinence in dogs. This is not a new drug but was previously a human drug now removed from the market . The side effects phenylpropanolamine like high blood pressure problems reported in humans that caused the human product recall have not been shown to occur in pets. Phenylpropanolamine has been used for many years to successfully treat incontinence in dogs. There were several years that it was not available when the FDA removed the human drug and it had to be reconsidered as a veterinary drug. Other treatments options were and are available and are sometimes still used.

Phenylpropanolamine's alternatives

Question: Hi, Dr. Mike -

I'm sure I won't be the first, nor the last, of your clients/correspondees to ask just what you will recommend to take the place of the now-defunct phenylpropanolamine. I am just sick that I can no longer obtain Dexatrim, or other OTC meds, to control BOTH Trudi's and her Boxer-sister-Fanci's (Fanci's is the typical spayed-female-leakage, brought on by advancing years) incontinence.

A brief note on our CRF gal, Trudi. Twenty-two months after the original diagnosis of chronic CRF was handed down, she is still doing remarkably well. The herbal iron tonic I discovered about 4 mos. ago has really created a huge improvement in her looks, stamina, eating patterns, demeanor. We continue to have small episodes of pancreatitis, which (so far) can be controlled by removing all food for 24 hrs. Strangely, although she LOOKS so great, her blood chem values have changed little; outwardly, the only sign that she's a CRF gal is her constant-and-profuse shedding.

Dr. Mike, I sure hope you'll be able to give us a tip as to what (either OTC or Rx) we can use to control the incontinence from now on. Thanks in advance.........your advice has always been valuable to us!

Regards, Rozanne

Answer: Rozanne-

Phenylpropanolamine is still available from some compounding pharmacies. I know of at least two in our area that still have the powder to make this medication and I believe that it may remain available through compounding pharmacies.

There are alternatives to phenylpropanolamine. The one currently being talked about the most on the Veterinary Information Network (www.vin.com, a service for veterinarians only) bulletin boards is impramine (Tofranil Rx), 1 to 2mg/kg of body weight every 12 hours, up to 15mg twice a day. I have not used this medication because we have had good success using diethylstilbestrol (DES) and have been able to obtain this medication from our local compounding pharmacy. We usually use 0.5mg per day for 5 days for small dogs, or 1mg per day for large dogs. We then try to lengthen the interval, usually reaching a once weekly or twice weekly dosage in most female patients. We usually try testosterone in male dogs but generally have to combine this with something else, such as phenylpropanolamine, so when our supply of this runs out, we will have to consider other options for our male patients, probably. I am hoping that when we run out of phenylpropanolamine the compounding pharmacies will still be able to get the medication.

Mike Richards, DVM 12/4/2000

PPA or phenylpropanolamine

Question: Dr. Richards,

Hope you are feeling better and out of the hospital.

I have a question about PPA. This is the 25 mg dog-strength Dimatapp that my 48 lb female shepherd mix was prescribed 2x per day for her urinary incontinence (began after her spaying). Recently the FDA pulled this drug because of the risk of stroke in young women. Should I be concerned about this drug for dogs? Her vet thinks that any risks with PPA are probably less than hormone treatment -- the next best option -- even with the FDA warning.

Have you heard something in the vet channels about this?

Eugenia

Answer: Eugenia-

The major risk with phenylpropanolamine appears to be an increase in the likelihood of stroke in women, if I understand the FDA's concerns correctly. The general feeling among veterinarians is that stroke risk is so low in both dogs and cats that this should not be a problem in pets. I am not sure what will happen to the supply of phenylpropanolamine, though. This is troubling, since I think that most vets do feel that it is a safer alternative than diethylstilbestrol, which is also not currently available except through compounding pharmacies. I am sure there will be some rethinking of the use of phenylpropanolamine in veterinary medicine in light of the withdrawal of the medication from human use and if reasons not to use it do surface, I will try to pass them on.

Mike Richards, DVM 11/15/2000

Phenylpropanolamine

Question: Our dog (almost 10 year old male Akila, neutered) has been prescribed phenylpropanolamine for his urinary incontinence. Would you tell us what, if any, side effects there are to this medication? We have written to you before regarding this problem with our dog, Major, and you were very helpful. You mentioned there might be a new medication available and I wondered if this was it - I don't think it is. Do you think this is worth trying with a male dog? From what I've read so far, it is mostly for females. Also, would there be any harm in taking this medication if the dog has, by any chance, bladder stones? I don't think he does -he had an ultrasound a few months ago - but he might. The reason I say this is because he had an incidence of urinary retention that resolved itself mysteriously ( this was the reason for the ultrasound). We would appreciate any information regarding side effects to this medication as Major also has seizures for which he takes phenobarbitol and potassium bromide. We would prefer not compounding his problems ( and ours!) if we can avoid it. On the other hand, we would be thrilled to find a solution to his incontinence as he keep us awake all night licking!!! Thank you.

Answer: J and L-

Phenylpropanolamine may cause restlessness, irritability and high blood pressure in some patients. In a patient who has a history of heart disease or high blood pressure it would be a good idea to think carefully about using phenylpropanolamine. We use this medication frequently and see side effects very rarely, though. It is potentially possible for a patient to have a decreased appetite or even to stop eating when using phenylpropanolamine. It is the active ingredient of Dexatrim (tm) so we have looked for this effect but have never seen it, that I can recall. I don't think that Dextrim would work as a diet aid in dogs based on our experiences.

I could not find any references to interactions between phenylpropanolamine and either phenobarbital or potassium bromide.

I would want to start the effort to see if incontinence would respond to medication using phenylpropanolamine because of our experiences with it. However, it does not work as well in male dogs as it does in female dogs, so you have to accept that it might not work.

If phenylpropanolamine doesn't work, there are other medications that can be used. Imipramine (Tofranil Rx) is a medication that works for incontinence that is new to me. However, it does increase the liklihood of seizures in a dog with this problem, so it is probably not a good idea for Major.

There are medications that help with problems that might be contributing to incontinence, such as urine retention. If you try phenylpropanolamine and it doesn't work, it would be a good idea to work with your vet to see if there are other contributing problems. Actually, it isn't a bad idea to do this, anyway, but I do think it is reasonable to try phenylpropanolamine for a short period of time before going through additional testing.