Treating Behavior Problems in Dogs
Medicines for the Treatment of General Anxiety continued...
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.