Behavioral Pharmacology and Psychotropic Medications
Key Concepts
- Drug classes: SSRIs (fluoxetine, sertraline), TCAs (clomipramine, amitriptyline), MAOIs (selegiline), benzodiazepines (diazepam, alprazolam), azapirones (buspirone), antipsychotics (acepromazine, haloperidol), alpha-2 agonists (dexmedetomidine), and others.
- Mechanisms: SSRIs block serotonin reuptake; TCAs affect serotonin and norepinephrine; benzodiazepines enhance GABA.
- Indications: Anxiety disorders, phobias, compulsive disorders, aggression (adjunct), cognitive dysfunction.
- Side effects: Sedation, GI upset, behavioral changes, serotonin syndrome, paradoxical excitation.
- Pharmacokinetics: Half-life, metabolism (hepatic), drug interactions.
- Regulatory: Many drugs are extralabel in veterinary behavior; informed consent required.
Traps
- Assuming immediate effect for SSRIs; they take 4-6 weeks to reach efficacy.
- Overlooking drug interactions (e.g., SSRIs with MAOIs can cause serotonin syndrome).
- Using benzodiazepines alone for long-term anxiety; risk of dependence and tolerance.
- Forgetting that behavior modification should accompany medication.
- Misunderstanding that acepromazine is not an anxiolytic; it's a tranquilizer and may worsen fear.
Worked Example
A cat with urine spraying receives fluoxetine. Owner should be informed it may take 4-6 weeks to see improvement. Rule of thumb: SSRIs are first-line for long-term anxiety; benzodiazepines are for short-term, situational use.