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
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
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