Dear Reader,

First of all, I’d like to assure my loyal readership that the quote attributed to me above is an utterance that would surely never pass my well-educated lips. It would be more likely for my dog to walk in and start quoting the Gettysburg Address than for the good Dr. Fike to use that kind of grammar, and the writer of the question surely knows it. It is much more likely that I said something like, “I ain’t gone know bo-diddley bout no stinkin’, self-aggrandizing, %#@$*!# internut!”

In general, it’s true that you can use Prozac in dogs for behavior problems such as aggression, although it is not the first drug we think of. A more commonly used antidepressant in dogs is Elavil (amytriptyline). Results with both drugs are unpredictable, and I have had much better success with these kinds of problems using sedatives, like acepromazine, or anticonvulsants, like phenobarbital or potassium bromide. When I HAVE used serotonin uptake inhibitors, I've had better success with Elavil than I have the few times I've used Prozac.

That’s what those medicines are, they’re called “serotonin uptake inhibitors,” and they've turned out to be pretty dandy drugs for certain psychological problems in humans. Here’s a little science, for the science nerd hiding in all of us. Inside the brain, in both humans and dogs, there’s the nerve cells, right? And they communicate with each other by sending little chemicals to each other where they touch; these chemicals are called “neurotransmitters.” There’s lots of different ones, with cool names like serotonin, norepinephrine, epinephrine, and others. After they are sent out by one nerve cell and they go and give their message to the neighboring nerve cell, then they are removed from the space between the two nerve cells by other chemicals called “enzymes.” Enzymes are put there for just that purpose, so the neurotransmitters won’t stay there and keep giving the same message over and over again. So they won’t stay there giving the same message over and over again. So they . . . . . OK, you get my point. These neurotransmitters are really a key to how the brain works, because they are the way the different nerve cells communicate with each other, and that’s what a fully functioning brain is all about, nerve cells communicating with each other. They are also key because altering the levels of these chemicals is one of the ways we are actually able to do something with medicines about what’s going on in the brain. And that’s what Prozac and its cousins are doing, they’re interfering with how the body eliminates serotonin from spaces between the nerve cells so that serotonin will stay in there longer and have a better chance to deliver its message.

Some people with psychological problems, like depression, obsessive compulsive disorder, and others, will get a benefit from having an increased amount of some of these neurotransmitters in their brains, especially serotonin. It’s not fully understood yet why that is, maybe these people don’t make enough serotonin on their own, so they benefit from having a leeetle extra. Or maybe the enzymes that degrade the serotonin when its job is done are there in excessive amounts, or are working in overdrive, destroying the neurotransmitters before they can do their job. Or maybe there’s not enough “receptors,” the little parts on the nerve cell that receive the serotonin, kind of like the way a lock receives a key, for the serotonin to deliver its message. Or, maybe there’s something else going on chemically in people’s brains, and having more serotonin around helps. The exact reasons how or why these medicines seem to help remain a mystery, but it’s a fact that they can be of huge benefit to some people.

Well, that’s all good for people, where a ton of research money is available, where there’s things like counseling and psychotherapy available so doctors can really get in and tell what kind of an effect a certain medicine is having on a person’s psyche. What these drugs do for animals with specific behaviour problems, on the other hand, is an inexact science, although it does make sense, in theory, that these drugs should have behaviour modifying properties in aggressive dogs. Whether they really work or not is, in my experience, variable, and will depend in part on how long the drug is given, what other methods, like training, are used concurrently, and the degree and exact nature of the problem, which, without actually getting into the dog’s head, is difficult to determine.

I don't think people really have a firm grasp on all the side effects of Prozac in dogs. In people, the list of possible adverse effects and precautions is long, ranging from eating disorders and weight changes to seizures, mania, nervousness, insomnia, nausea and other digestive problems, dizziness, rash, abnormal vision, and the list goes on. In general, these are things that happen to a tiny minority of the people that take Prozac. Just about any drug, any herb, any therapy in the world has the potential for "side effects" in some of the individuals that use it; that's no reason not to use the right drug for the right problem. But people think of Prozac these days because it's trendy and it has enjoyed quite a bit of success with people with certain kinds of neuroses, and applying that thinking to dogs with behavior problems may or may not make much sense.

Still, though, it’s a thorny problem that confronts you. Your dog's aggressive behaviour may have some pretty ugly "side effects," too, like hurting your other dog, or maybe needing to find a new home, or worse. You’re wise to be thinking of ways to address it. Drug therapy can definitely be part of the answer; here’s a few more points to consider.

One possible key to success in managing this type of problem is to remember that we truly have to manage our animals. Some animals are just not going to get along with each other, no matter what. You may have to keep them physically separated. Nobody wants to do that with their dogs, we like to think of them as all members of our big, happy family, and we’d like them all to get along and love each other as much as we love each of them. But, that may never be the case. So keeping them separate is an option.

You can also try modifying other things about their environment. Keep them in a different space, try feeding them at different times of the day, vary their routines, notice when the trouble seems to start and what’s going on when that happens. Do they fight at feeding time? Maybe you could just separate them then. Do they fight when other dogs walk by? Separate them during the time when people are walking their dogs in your neighborhood. It’s hard to tell what’s setting a dog off, but if you experiment with things like this it’s possible you could hit on a technique that will work.

I read about a technique for establishing order in the household that makes a lot of sense to me, but everyone I’ve told this to always hates the idea. This is dog psychology, based on how animals relate with each other, and it bears scant resemblance to how we would treat our children. Here it is. If a dog is aggressive to another dog, you punish not the dog that is the aggressor, but the one that’s getting pushed around. Here’s the logic. In dog society there is a hierarchy, a ranking in the social order that must be followed for there to be peace and harmony. Any two dogs in a group need to know where they rank in relationship to each other, are they higher than the other one, more dominant, or lower, more submissive? Dogs have varying needs to be dominant over each other, although the general rule is to try to be dominant over as many other dogs as possible. But, when there is a clear pecking order, they don't really seem to care where they are in it, as long as it’s clear to everyone what the ranking is. This is the basis for dog-to-dog interactions. This is also one way to look at training dogs; the human in the interaction has always got to be at the top of the pecking order, the “alpha wolf” of the pack, if you will, so that the person’s dogs will listen to her and be trainable by her. How that works in a conflict between two dogs is that the person, the alpha wolf, punishes the dog that’s being beaten up on. You don’t actually hurt the submissive dog physically, of course, but you can admonish her, growl at her, do things like that to show the aggressor dog that you, the “alpha wolf,” are on her side. By intervening and showing her that she’s dominant by siding with her against the submissive one, you tell all parties concerned that, yes, the aggressor is dominant. That creates stability. Without it, there will be uncertainty in the pack. The dominant one will try to establish the pecking order by being aggressive, the alpha wolf (you) will come along and act like it’s not ok for the dominant one to be dominant anymore, there will be confusion over where everybody stands in the hierarchy, and the aggressor will have to prove over and over again that she IS the dominant one over the submissive one, which leads to injured dogs and big vet bills. There’s no justice here, but the idea is to end the violence, which is all you’re after, anyway. It’s a way of speaking “dog language” in such a way that they can all understand what the social order is and they don’t have to keep tearing each other up trying to figure it out. You can see how that would be hard to swallow, because the natural human instinct of a care-giver, a nurturer, would be to comfort the afflicted and punish the aggressor, that’s what we’d probably do if these were our own children, that’s what would seem to be the fair way. But, these aren’t children, even though we love them so. They’re animals, and this is the way to get through to them.

When it comes to behaviorists, I usually recommend Lou Brady; he’s worked with some friends of mine with their animals and they always give me rave reviews. There are other people around town that are animal behaviorists, like Tom Miller, the son of Dr. Tom Miller from Valley Animal Hospital. I don't have any personal experience with any of these people in their capacity as behaviorists, but I do know Lou, he's been a client of mine, he seems like a really nice guy, very knowledgeable, and all the people I've referred to him have given me good reports.

Lastly, there are pharmacologic options other than prescription drugs, in other words, herbal medicine. Whether or not these herbs do anything and how exactly they work is an area of active debate, and I definitely plan on throwing my two cents in, but that’s going to be a whole other chapter. For now, suffice it to say that these remedies are unproven, but at least the ones I’m going to tell you about here are unlikely to do any harm, and they might help. I include these last because that’s where I rank them in this list of possible solutions to your problem; they are the least likely of any of the things that I’ve discussed here to do any good, but anyone who’s motivated enough to go out and try them will probably also be motivated to try lots of things and get creative to solve the problem, and that’s where success will most likely lie. Three herbs that might be useful in this situation would be Valerian root, St. John’s Wort, and Chamomile. If you want to try these, only use one at a time. Valerian root would be my first choice. It is widely used in Europe for stress, anxiety, and nervous irritability and is reported to have a very low toxicity in animals. St. John’s Wort has become popular in the USA in the last few years for use in people with depression and sleep disorders. At high doses it could cause an allergy to the sun, “photosensitization,” so keep that in mind here in southern Arizona! Chamomile is one I have personal experience with, it is sold as a calming tea, and I can vouch that it is a pleasant drink to have with a little honey in it in the evening. Drink a cup of it and read your favorite religious text and you won’t want to fight with anyone! I rank it last of the lot because it is probably the mildest of a mild group, and there are also reports of allergies to it in some individuals. Dosing these herbs is an inexact science; most authorities say that the recommended doses that you'll find written on the label of the product you buy are for 150 pound humans, and you should dose your dogs accordingly, which means giving your 50 pound dog about a third of the adult dose. The safest approach is to start out conservatively and work your way up to higher doses. These herbs are sold over-the-counter and are widely available in drug stores and supermarkets.

Good luck! It is not easy to manage two dogs with aggression problems in a household; many times the end result can be that one of the dogs has to go to a new home, or there may be outcomes even more tragic. Let me know how it goes.

Feedback for this page

One alert reader recently sent this in..."I was reading your response regarding prozac and I thought it was very well written, except.... well, it's not a big deal but you said Prozac is a 'serotonin uptake inhibitor' and in fact it is a 'serotonin REuptake inhibitor.' Well, really it's a 'selective serotonin reuptake inhibitor' which is where the acronym SSRI comes from. Just thought you might want to know."

The writer of the letter is a friend of mine and a medical student; it's really great to have students around who'll keep you on your toes.

Dear Reader,

You're correct, Prozac does belong to a class of drugs known as "SSRIs." However, there is nothing wrong with calling Prozac a "serotonin uptake inhibitor," because that is what it does. Wouldn't "reuptake" imply that something had already been taken up once before, and was now being "re-" uptaken? As I'm sure you know, that is not the case. Serotonin is made, using the amino acid L-tryptophan, in the central nervous system neuron from which it is released. It isn't "taken up" by the body somewhere. So, when a serotonin molecule is removed from the synaptic space after it binds with the post-synaptic receptor, it is undergoing "uptake" rather than "reuptake," is it not? In the Physician's Desk Reference (the book doctors use that lists all the drugs and all the information about them,) the first line, under Clinical Pharmacology, states "...the action of fluoxetine (Prozac) is presumed to be linked to its inhibition of CNS neuronal uptake of serotonin." Uptake, not REuptake. And, if you want to get REALLY picky, "reuptake" isn't even a word, at least not according to my Webster's Ninth New Collegiate Dictionary and the 26th edition of Dorland's Illustrated Medical Dictionary.

Here's where you got fooled -- it's typical "medicalese" when we call these things "reuptake" inhibitors as opposed to "uptake" inhibitors. A lot of doctors like to add a syllable anywhere they can to make what they're talking about sound cooler, even the big kahuna doctors -- ESPECIALLY the big kahuna doctors -- who discover stuff like fluoxetine. My own preference is to keep things as simple as possible when I'm trying to explain things to people. I can deal with complexity in medicine, but then, I'm a doctor. The whole purpose of my website is to take the unintelligible and make it understandable to all people; I feel that's a big part of every doctor's job. If it would help people understand their dog's aggression for me to use medical acronyms like "SSRI," then I would. But I don't think it does.

For you, and for other medical students and for doctors, I believe it's a question of specific, medical-conference-style accuracy, the kind of thing doctors need to have when they're discussing these complex subjects amongst each other, the kind of talking that's required of one in order to be absolutely accurate and unambiguous when discussing a technical subject with other experts in the field, it's a question of that versus trying to be plain and understandable to people who aren't experts in the field but are nevertheless interested. It's not always an easy path to follow, and you're right to be struggling with it at this stage of your career.

Good luck! I'm glad to hear "The Veterinary Advisor" is being used as a resource for your medical education!

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