Over the last two decades, the role of the domestic dog has undergone significant change. Dogs who used to live in a house with family members around all day, every day—and who had a big backyard in which to play and chase rabbits—may find themselves in an empty house 8 to 10 hours a day and being taken on a leash to a place to eliminate. Some dogs have a difficult time adjusting to this lifestyle, and many behavior problems occur because dogs are on their own and entertaining themselves inside the house. Other problems arise because dogs are more intimate members of the family than they were before and share closer quarters with their human families. Still other problems occur because of the difficulty dogs have adapting their natural behavior’s to the limited environment of the modern urban home.
Behavior problems arising from the limitations imposed by the modern urban environment can be complex and difficult to treat. Anxiety is often a factor. In such situations, medication can help with treatment success.
Is Medication Necessary?
Some pet parents don’t want to give their dog behavioral medication. They’re not comfortable treating behavior issues with drugs and would rather resolve the problem through training and behavior modification. This reaction is understandable. However, some problems can be resolved more quickly and with less distress (for the dog and the pet parent) if behavior medication is added to the treatment plan.
In an ideal world, the most effective approach to treating a behavior problem is behavior change training. Behavior modification treatments designed by knowledgeable, qualified professionals treat the problem behavior by either changing the dog’s perception of a situation or a thing, by changing the consequence of the dog’s behavior, by giving the dog an acceptable behavior to do in place of the problem behavior, or by a combination of these things. (Please see our article, Finding Professional Help , for help choosing and locating a qualified expert in your area.)
However, with many problem behaviors related to fear, medication is necessary to reduce the dog’s fear to a level that allows treatment to begin. Please see our article, Desensitization and Counterconditioning  for information about these effective treatments that are commonly used for fears, phobias, anxiety and aggression.
Can Medication Be Used Instead of Behavior Modification?
Behavioral medication alone isn’t usually effective for resolving a behavior problem. For the dog, medication serves to make a situation tolerable but not necessarily acceptable. Behavior modification can then be used to make the situation acceptable. For instance, if a dog is afraid of thunder storms, medication can ease the dog’s fear enough that he can tolerate the storm and undergo the counterconditioning necessary to treat his fear. But it’s the counterconditioning that helps him overcome his fear. In addition, many dogs can develop behavior habits because of a problem that requires medication. The medication can help the core problem, but behavior modification is still necessary to treat the accompanying behavior habits.
Which Medicines Are Best for What?
Five types of medicines are usually used to treat behavior problems in dogs. These are benzodiazepines (BZs), monoamine oxidase inhibitors (MAOIs), tricyclic antidepressants (TCAs) and selective serotonin reuptake inhibitors (SSRIs). The following is a table that shows different behavior problems in dogs that have been successfully treated with behavior change training and medicine.
General Timidity and Fear of New Things
TCA, SSRI, 5-HT agonist
Thunderstorm or Noise Event Phobia
Distress at Being Left Alone (Separation Anxiety)
Compulsive Behavior (repeating the same short
response or sequence over and over again)
TCA, SSRI, 5-HT agonist
TCA, SSRI, 5-HT agonist
Medicines for the Treatment of Sudden or Severe Fear and Panic
Some dogs experience fear only in specific situations, such as during fireworks or other events with loud noises. The benzodiazepines can help in these situations by reducing fear as needed right when these situations occur. Benzodiazepines take effect quickly, so they can treat impending fear within a short period of time—the same way an aspirin relieves a headache shortly after you take it. In contrast, most other drugs for alleviating fear need to be taken daily for several weeks before they produce results—just like antibiotics need to be taken a few days before they begin to fight bacteria. A minor drawback is that BZs must be given to the dog before the fearful event begins. Optimally, the medicine should be given one hour before the beginning of the scary event, or at minimum, it should be given before the dog shows any signs of fear or worry, such as stress panting, trembling, tail tucking, pupil dilation, sweating paw pads, etc.
Some common benzodiazepines are diazepam (Valium®), alprazolam (Xanax®), chlordiazepoxide (Librium®), lorazepam (Ativan®) and clonazepam (Klonopin®). Benzodiazepines work by increasing the activity of a chemical in the brain that interferes with activation of the fear networks.
You can only know if a drug is working if you have an idea of what effects to expect. The following list provides the expected reactions in dogs to different doses of benzodiazepines:
- At low doses, benzodiazepines ramp down excessive behavior and reduce excitability.
- At moderate doses, benzodiazepines reduce anxiety. Dogs who are afraid will be less fearful and more likely to act normally. At these doses the drug can also increase friendly and interactive behavior.
- High doses of benzodiazepines produce sedation, including impaired movement and thinking, and disorientation. They also produce sleepiness and cause vomiting. Benzodiazepines affect some of the same parts of the cells in a dog’s brain as alcohol, and so they produce similar effects.
Benzodiazepines have some unwanted side effects, including increased appetite and sleeplessness. Sleeplessness may seem contradictory, but this medicine can actually produce increased anxiety in some dogs. Although not common, this side effect seems to occur most often when the medicine is given after the dog has already begun to show signs of anxiety.
Benzodiazepines are also inappropriate for the treatment of aggression, because they can sometimes reduce inhibition. This means that although the dog may not react as quickly to a frightening or disturbing event, if he does react he might behave aggressively. Lastly, benzodiazepines can cause addiction if they are given many times a day for more than three weeks.
Benzodiazepines can also interfere with learning and memory, so they aren’t good choices for long-term use with training and behavior modification. Because of this, if a benzodiazepine is necessary because of excessive anxiety or fear, this type of medicine is best used initially and then gradually discontinued.
Benzodiazepines are metabolized in the liver and excreted through a dog’s kidneys, so if your veterinarian advises you to treat your dog’s fear with a benzodiazepine, she should check with a simple blood test to make sure that these organs are working well before beginning treatment. If your dog has had problems with his kidneys or liver, be sure to let your veterinarian know.
Medicines for the Treatment of General Anxiety
Some dogs suffer from a more generalized form of anxiety that leaves them nervous in many everyday situations. Benzodiazepines are not a good choice for everyday, ongoing treatment, so they aren’t appropriate for dogs with generalized anxiety. These dogs do better with treatment that can be continued for a period of time rather than given in anticipation of frightening events. The medicines that help dogs with general anxiety problems are TCAs, MAOIs and SSRIs.
Tricyclic antidepressants (TCAs) were originally used to treat depression in people. They work primarily by increasing serotonin and norepinephrin—two neurotransmitters that are involved in regulation of emotional activity. They also affect other neurochemicals involved in emotional reactivity. The TCAs prescribed most for dogs are amitriptyline (Elavil® or Tryptanol), clomipramine (Clomicalm® or Anafranil®), doxepin (Aponal®), imipramine (Antideprin or Deprenil), desipramine (Norpramin® or Pertofrane) and nortriptyline (Sensoval). Every dog is unique behaviorally and physiologically, so one TCA might not work well in a dog whereas a different TCA in the same dog could have excellent results.
Although TCAs were originally labeled to treat depression, they also reduce anxiety, manage compulsive behavior and can help people with anger problems. In dogs they have been used successfully to help with treatment of separation anxiety, general anxiety and compulsive behavior problems like compulsive licking. For instance, amitriptyline is a good choice for treating generalized anxiety and separation anxiety. Studies have shown that clomipramine is quite beneficial when used in combination with behavior modification for treating separation anxiety. This medication is approved for dogs by the FDA. (It’s sold under the name Clomicalm®.) It‘s also effective for reducing compulsive behavior.
TCAs are prescribed for daily use. If the medicine isn’t taken every day, it won’t work to treat the problem behavior. TCAs are not usually effective the first day—or even the first few days that they are taken. Because at least some of their effectiveness comes from the changes they make to the brain, they must be taken for at least two to three weeks before they produce results. Treatment should continue for at least two months before a decision is made regarding the success of the drug.
TCAs are metabolized in the liver and excreted through the kidneys of a dog, so if your veterinarian advises you to treat your dog’s behavior problem with a TCA, she should give your dog a simple blood test to make sure that these organs are working well before beginning treatment. If your dog has had problems with his kidneys or liver, be sure to let your veterinarian know about your dog’s history. Recheck blood tests are recommended every year (twice a year in older dogs) to ensure that the medicine has not damaged the liver or kidneys.
Some drugs, such as amitraz (a chemical found in some tick repellant collars), have been found to cause dangerous problems such as lethargy, weakness and increased heart rate when used on dogs who are taking imipramine. Pet parents should read the ingredients of their flea and tick treatments carefully and avoid amitraz if their dog is taking or has taken imipramine.
TCAs can increase water retention, and water retention produces dry mouth. Some dogs might foam at the mouth, and they may also be extra thirsty. Because they are thirsty, they might drink extra water and then have to be let outside more. Water retention can also lead to constipation and even diarrhea, and all of these things can show up as house soiling problems. TCAs can also cause a sudden increase in heart rate.
Monoamine Oxidase Inhibitors
Monoamine oxidase inhibitors (MAOIs) work on similar neurotransmitters as TCAs, but they work differently and with less selectivity, so they have a more general effect on the brain. Selegiline (Anipryl®) is an MAOI that affects the neurotransmitter dopamine. It’s the only MAOI that is used with any regularity in dogs. It’s used to treat cognitive dysfunction in elderly dogs. Studies indicate that selegiline may slow aging of the brain. (Please see our article, Behavior Problems in Older Dogs , for more information on how to preserve the quality of life of your older dog).
Some MAOIs can have dangerous side effects in dogs who have eaten cheese. Selegiline does not fall into this category, but because some humans have been known to react to cheese when on selegiline, pet parents should avoid giving their dog cheese when he’s taking selegiline. MAOIs should not be used with SSRIs because the combination can increase serotonin to unhealthy levels.
Selective Serotonin Reuptake Inhibitors
SSRIs affect the brain chemical serotonin. Common SSRIs are fluoxetine (Reconcile® or Prozac®), paroxetine (Paxil®), sertraline (Zoloft®) and fluvoxamine (Luvox®).
Fluoxetine and sertraline have been used successfully to treat a number of anxiety-related behavior problems such as separation anxiety and fear of people, other animals or other things that the dog may encounter daily. SSRIs are also useful in reduction of compulsive behavior in dogs. SSRIs may be prescribed for certain aggression problems, but the effects are mixed and can, in some instances, make a dog worse. Only consider SSRIs for your dog’s aggression if you have been advised to do so by a veterinary behaviorist or Certified Applied Animal Behaviorist.
SSRIs are metabolized in the liver and excreted through the kidneys. Even if your veterinarian does a pretreatment blood test to check liver and kidney health, be sure to let her know of any medical problems with your dog. It’s a good idea to have your dog’s liver and kidneys rechecked each year if he is kept on an SSRI.
SSRIs should not be used with MAOIs because the combination can increase serotonin to unhealthy levels.
SSRIs need to be taken every day to be effective. If the medicine is not taken every day, it won’t work to treat the problem behavior. SSRIs are rarely effective the first day, and in fact can increase anxiety in some dogs before they begin to have therapeutic effects. Because SSRIs create changes in the brain, they must be taken for at least six weeks before they produce therapeutic results. Any decisions regarding the success of the treatment should be postponed until the dog has been on the medicine at least four months.
Because SSRIs require a few weeks to build up in the dog’s system and take effect, some people will also use other medicines at the beginning of treatment. One choice is to use benzodiazepines when the dog may encounter a frightening thing or event. Another choice is to use a medicine known as a serotonin agonist, which can sometimes be useful at the beginning of SSRI treatment. The most common is buspirone, sold under a number of brand names, including Bespar and BuSpar®.
Serotonin (5-HT) Agonists
Buspirone (BuSpar or Bespar) is the only 5-HT agonist that’s used regularly in companion animal behavior. As mentioned, it’s sometimes used in conjunction with SSRIs and TCAs when treatment is begun, but it’s also sometimes used by itself.
Like other medicines that act on serotonin, buspirone needs to be taken every day to be effective. If the medicine isn’t taken every day, it won’t work to treat the problem behavior. Buspirone usually requires about thee weeks to show an effect, although this may be shortened if it’s taken in addition to SSRIs.
Giving Your Dog His Medicine
If you decide to use a behavioral medication to help your dog overcome a behavior problem, you might run into a challenge when you try to give him his medicine. It can be difficult to get dogs to swallow pills, and some dogs get so upset by the pilling process that they start avoiding their pet parents altogether. To learn how to give your dog the medicine he needs in the least stressful way possible, please see our article on Giving Your Dog a Pill .
Seek the Advice of an Experienced Professional
This article is intended to help pet parents understand various behavioral medications used in dogs. It’s not intended as a guide to choosing behavior medications. If your dog suffers from fear, anxiety, behavior compulsions or any other behavior problem for which you’re considering behavioral medication, be certain to first consult with a Certified Applied Animal Behaviorist (CAAB or ACAAB) or a Diplomate of the American College of Veterinary Behavior (Dip ACVB). These animal behavior experts can evaluate your dog’s behavior problem, help you develop a treatment plan, give you advice on suitable medications, and work with your veterinarian to maximize the success of your dog’s treatment program. For help in locating a behavior expert in your area, please see our article, Finding Professional Help .