Behaviour Drugs

Question 1

Antidepressants

Answer 1

Used them to modify certain behaviours and reduce anxiety

- not to tx depression in animals

Question 2

Clomipramine -> Clomicalm

Answer 2

Tricyclic antidepressants/TCA

Inhibits reuptake of serotonin and NE

Use in dogs and cats
Tx of anxiety states = separation anxiety, aggression, urine marking/spraying, generalized anxiety, excessive vocalization, phobias
- and compulsive behaviours (stereotypies)

Can be used as sole tx or in combo w/ anxiolytics
- takes 4-6 wks before full therapeutic effect

Side effects

• mild sedation (due to antihistamine effect in CNS)
• anticholinergic effects = dry mouth, increased HR, urine retention and constipation
• hypotension and arrhythmias

Question 3

Fluoxetine -> Prozac

Answer 3

Antidepressant
SSRI = selective serotonin reuptake inhibitor

Tx of anxiety states

• separation anxiety, aggression, urine marking/spraying, generalized anxiety, excessive vocalization
• phobias

Can be used as sole tx or in combo w/ anxiolytics
- takes 3-4 wks before full therapeutic effect

Side effects
- mild sedation, GI irritation (decreased appetite, V/D), excessive vocalization, seizures

Question 4

Trazodone

Answer 4

Antidepressant
SARI = serotonin antagonist/reuptake inhibitor

At low doses -> antagonizes post-synaptic 5HT2, H1, and a1 receptors
- can be agonist for 5HT1 and GABA
So effect is complicated

Can be used in combo w/ other SSRI and TCAs in dogs

Dogs -> T1/2 = 3h and 85% F

use extra-label

Question 5

Anxiolytics

Answer 5

Benzodiazepines

• Diazepam (Valium)
• Midazolam

These are targeted substances

Tx of anxiety states, fears, phobias
- efficacy for urine spraying
Can be used solely or in combo

Side Effects

• sedation, ataxia, increased appetite and friendliness, paradoxical excitation, maybe hepatic necrosis
• can interfere w/ learning and memory

Question 6

Antipsychotics

Answer 6

Phenothiazines => acepromazine
Butyrophenone => azaperone

Narcotic antagonists => naloxone for opioid overdose

Question 7

Serotonin Syndrome

Answer 7

When have too much serotonin levels in CNS
- w/ combo of TCA, SSRI and/or MAOi –> occurs when using multiple drugs impacting serotonin in conjunction

Autonomic signs –> tachycardia, hypertension, hyperthermia, diarrhea

Neurological signs –> tremors, myoclonus, hyperreflexia (looks like a seizure)

Mental status –> restlessness, paradoxical anxiety, confusion, agitation, coma

Other –> metabolic acidosis, renal failure, DIC

Tx = supportive therapy
- IV fluids, external cooling, maybe diazepam for sedative effects

Question 8

Acepromazine

Answer 8

Antipsychotic

Use in small and large animals

CNS effect due to dopamine (D2) antagonism

Label indication = non-specific sedation
Non-label -> motion sickness

Injectable and oral forms
- but poor F

Side Effects

• hypotension -> dose dependent effect and gets worse if given w/ other sedative drugs
• extrapyramidal signs
• penile prolapse in horses
• CYP mediated interactions

Question 9

Extrapyramidal Signs

Answer 9

Occurs if excessive inhibition of dopamine receptors = a dopamine and Ach imbalance

Manifests as involuntary m movements -> looks like seizure but isn’t one

Tx -> IV diphenhydramine (Benadryl)

Question 10

Azaperone (Stresnil)

Answer 10

Sedative for pigs and used in wildlife immobilization protocols