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July/August 2014 Today's Veterinary Practice 65 On YOur BesT BehaViOr | Q & a: The use OF MeDiCaTiOns in BehaViOr TheraPY tvpjournal.com months for full effect, while others, such as benzodi- azepines and other sedatives, act more immediately. • Loading period: The initial loading period of some drugs should be considered when planning therapy and duration of treatment. Once it's been determined that the patient's response to medication is adequate, a reasonable duration of ini- tial therapy would be at least 6 months, which allows a generous period of time for behavior modification (learning). Discontinuation Abrupt discontinuation of medication may cause re- bound anxiety or exacerbate behavior problems. Any medication should be tapered gradually (weeks to months, depending on duration of therapy); a good guideline is a 25% reduction every 1 to 2 weeks. Slow discontinuation also allows the owner to report any reappearance of the behavior problem, in which case a lower, but effective, dose can be continued or the original dose resumed. WhaT MeDiCaTiOn shOuLD Be useD? Antidepressants The most commonly used anxiolytic agents are: • Selective serotonin-reuptake inhibitors (SSRIs), such as fluoxetine (Prozac, lilly.com), sertraline (Zoloft; pfizer.com), or paroxetine (Paxil, gsk.com) • Tricyclic antidepressants (TCAs), such as clomip- ramine (Clomicalm, novartis.us) and amitriptyline. • Selegiline (Anipryl, zoetisus.com), a monoamine oxidase inhibitor (MAOI) approved for treatment of canine cognitive dysfunction syndrome or senile dementia. Fluoxetine (no longer available as a veterinary The Importance of Informed Consent Many drugs used in veterinary behavioral medicine fall into the following 2 categories: 1. Human psychiatric agents not licensed by the Food and Drug administration (FDa) for use in companion animals 2. FDA-approved drugs for use in dogs with specific behavior problems, such as fluoxetine (veterinary product no longer available) and clomipramine for separation anxiety and sele- giline for cognitive dysfunction syndrome; how- ever, administration for other behaviors, such as anxiety-based aggression, is extra-label. When recommending these drugs, inform clients that the use is off- or extra-label. it may be advisable to have the owner sign a release form that lists the risks, limitations, and potential adverse effects of the drug being prescribed. TaBLe 2. Common Medications used for Ca- nine Behavioral Problems (alpha Order by Class) DRUG DOSE POTENTIAL ADVERSE EFFECTS Azapirone Buspirone 1–2 mg/kg PO Q 8–24 h • aggression disinhibition (anecdotal) • increased anxiety Benzodiazepine Alprazolam 0.02–0.1 mg/kg PO Q 8 h or Prn • agitation • ataxia • Polyphagia • sedation Clorazepate 0.5–2.2 mg/kg PO Q 8 h or Prn Diazepam 0.5–2.2 mg/kg PO Q 8 h or Prn Monoamine Oxidase Inhibitor Selegiline 0.5–1 mg/kg PO Q 24 h • agitation • Disorientation • Vomiting/ diarrhea Serotonin Antagonist-Reuptake Inhibitor Trazodone 3–5 mg/kg PO Q 8–24 h or Prn • increased anxiety • sedation Selective Serotonin-Reuptake Inhibitor Fluoxetine 0.5–2 mg/kg PO Q 24 h • agitation/ increased anxiety • inappetence* • Lowered sei- zure threshold • sedation • Tremors Paroxetine 1 mg/kg PO Q 24 h Sertraline 1–3 mg/kg PO Q 24 h Tricyclic Antidepressant Amitriptyline 1–4 mg/kg PO Q 12 h • Constipation • Decreased appetite • Dry mouth/dry eyes • increased anxiety • Lowered sei- zure threshold • sedation • Tachycardia/ tachyarrhyth- mia • urine retention Clomipramine 1–3 mg/kg PO Q 12 h * Less likely with paroxetine and sertraline