22. behavior modifying drugs

Chapter 22

Behavior-Modifying Drugs

Copyright © 2011 Delmar, Cengage Learning

Basic Terminology

• The use of drugs to treat problem behaviors is only a small part of treating animal behavior problems– Must correctly diagnose the condition, examine the

social conditions, and alter external stimuli

• Potential side effects of long-term use– Liver, kidney, and cardiovascular problems

• Used extra-label– Must have veterinarian/client/patient relationship


Classes of Behavior-Modifying Drugs

– Anti-anxiety drugs• Antihistamines• Benzodiazepines• Phenothiazines• Azapirones• Barbiturates

– Antidepressants• Tricyclics• Monoamine oxidase inhibitors• Selective serotonin reuptake inhibitors

– Hormones• Progestins• Estrogen• Testosterone inhibitors


Anti-anxiety Drugs

• Anti-anxiety drugs attempt to decrease anxiety• Types of anti-anxiety drugs

– Antihistamines produce some degree of sedation because they suppress the CNS

• Used to treat anxiety associated with pruritus; the antipruritic effects of antihistamines appear to lessen this anxiety as well

• Examples include hydroxyzine and diphenhydramine


Anti-anxiety Drugs

• Types of anti-anxiety drugs (cont.)– Benzodiazepines

• Are chemically related compounds used to relieve anxiety; appear to work on the limbic system of the brain by potentiating GABA

• Bind to specific sites in the brain; appear to produce sedation and relieve anxiety

• Used to treat aggression, urine spraying, and noise phobias• Examples include diazepam, chlordiazepoxide, lorazepam,

flumazenil, and alprazolam


Anti-anxiety Drugs

• Types of anti-anxiety drugs (cont.)– Phenothiazines

• Are chemically related compounds that work by antagonism of dopamine (increased dopamine levels are associated with some psychotic diseases)

• Used to treat aggression (however, may make animals more reactive to noise)

• Examples include chlorpromazine, acepromazine, promazine, perphenazine, and prochlorperazine


Anti-anxiety Drugs

• Types of anti-anxiety drugs (cont.)– Azapirones

• Chemically different from other anti-anxiety drugs; do not cause sedation

• Work by blocking serotonin; used to treat urine spraying and anxiety-associated aggression

• An example is buspirone– Barbiturates

• Have anti-anxiety action due to their ability to cause CNS depression (they have an effect on GABA)

• Used to control vocalization in cats and seizure-like anxiety in dogs

• Examples include phenobarbital and carbamazepine


Anti-anxiety Drugs

• Types of anti-anxiety drugs (cont.)– Types of anticonvulsants

• Carbamazepine– used to treat seizure-like anxiety in dogs– Absorbed slowly by the gastrointestinal tract– May enhance the metabolism of other drugs– The main side effect is hepatotoxicity


Antidepressant Drugs

• Antidepressant drugs are used to treat various mood changes (including aggression) and cognitive dysfunction in animals

• Transmission of nerve impulses between two nerves or between a nerve and tissue takes place via the release of neurotransmitters from storage sites at the nerve terminal

• After the neurotransmitter combines with the appropriate receptors, reduction of neurotransmitter concentration occurs– One mechanism involves the reuptake of neurotransmitter– Another mechanism involves destruction of neurotransmitter by

monoamine oxidase (MAO)



• Tricyclic antidepressants (TCAs)– Work by interfering with the reuptake of serotonin by the

presynaptic nerve cell; its metabolites inhibit the reuptake of norepinephrine

– Increases the concentration of neurotransmitter at postsynaptic receptors in the CNS

– Used to treat separation anxiety, pruritic conditions, and compulsive disorders in animals

– Side effects include anticholinergic effects, liver problems, and thyroid effects

– Examples include amitriptyline, imipramine, clomipramine, and doxepin



• Monoamine oxidase inhibitors (MAOIs)– Work by inhibiting the enzyme monoamine oxidase,

thus reducing the destruction of dopamine, norepinephrine, and epinephrine

– MAOIs irreversibly inhibit MAO– Used to treat cognitive dysfunction in dogs– Side effects include hypotension, drowsiness, and

anticholinergic effects– An example approved for dogs is selegiline; extra-

label examples include phenelzine, isocarboxazid, and tranylcypromine sulfate



• Selective serotonin reuptake inhibitors (SSRIs)– Work by inhibiting serotonin reuptake, resulting in

increased serotonin neurotransmission– Used to treat depression, aggression, anxiety,

phobias, and compulsive disorders– Side effects are few– Examples include fluoxetine, sertraline, and

paroxetine


Hormones

• Progestins and estrogens have calming effects due to their suppression of the excitatory effects of glutamine and their suppression of male-like behaviors

• Side effects include mammary gland hyperplasia, endometrial hyperplasia, bone marrow suppression, and endocrine disorders

• Examples include– Diethylstilbestrol: used for urinary incontinence– Medroxyprogestone acetate: used to treat male-like behaviors– Megestrol acetate: used to treat urine spraying, anxiety,

aggression, and dermatitis conditions


Hormones

• Testosterone inhibitors inhibit the production of testosterone or block enzymes that convert testosterone to dihydrotestosterone (its potent form)

• Used to treat aggression in male dogs• An example is delmadinone, which is used to

treat aggression in male dogs• The human product finasteride is used to treat

benign prostatic hyperplasia and may be used in the future in veterinary medicine


Pheromones

• Chemical that trigger a behavioral response between members of the same species

• Many different types such as sex and territorial pheromones

• In most animals pheromones have a general calming effect

• No significant side effects are noted for the use of pheromones


Types of Pheromones Used in Veterinary Medicine

• Dog Appeasing Pheromone (DAP)– Produced by females to provide a feeling of safety and

comfort to the young– used to treat separation anxiety, destruction,

excessive barking, house soiling, phobias, and excessive licking

• Feline Facial Pheromone (FFP)– Made by cat cheek gland secretions– Used to treat urine marking or spraying, avoidance of

social contact, stressful situations, inter-cat aggression, vertical scratching, or appetite loss


Types of PheromonesUsed in Veterinary Medicine

• Equine Appeasing Pheromone (EAP)– A maternal pheromone found in the “wax area” close

to the mammae of a nursing mare – is administered in 2 sprays into each naris 30 minutes

before a stressful event– Is used in horses to alleviate stressful situations such

as transport, shoeing, clipping, new environments, and training


Health & Medicine

22. behavior modifying drugs