GI Drugs- appetite

Question 1

2 issues with appetite

Answer 1

1. Obesity
2. Animals that don’t want to eat due to illness (especially cats)

Question 2

Inter species differences

Answer 2

-Cannot compare data from different species
-ex. Many dogs have genetic defect which prevents them from feeling full

Question 3

Site of physiology appetite control

Answer 3

Satiety center is in the hypothalamus

Question 4

Hormones involved in appetite control

Answer 4

-cholecystokinin
-Glucagon-like peptide 1 (GLP-1)–> semaglutide- GLP 1 receptor agonist peptide
-Nefstatin/ghrelin
-others

Question 5

Neurotransmitters involved in appetite control

Answer 5

-Serotonin and peptide YY stimulates satiety

-NE

Question 6

Dirlotapide/Slentrol

Answer 6

-Not in Canada, in US
-results in decreased fat absorption, so enterocytes keep lipids and feel satiated and tell hypothalamus that they are full
=weight loss due to decreased food intake

-oral solution; start with low dose
-adverse effects: diarrhea, anorexia, emesis, liver enzymes increased

**don’t give to cats (because prone to hepatic lipidosis) or people

Question 7

Orlistat

Answer 7

-pancreatic lipase inhibitor
-low oral bioavailability (because does not need absorption; works in gut)
-decreased fat digestion/absorption = diarrhea

Question 8

Mirtazapine

Answer 8

-human antidepressant
-serotonin and NE effects
-stimulates individuals to eat
most effective drug currently for vet med appetite stimulant

Question 9

Mirtazapine effects

Answer 9

-increase NE release (via pre synaptic alpha 2 receptor inhibition)

-increase specific serotogenic receptor (5-HT1) activity

-antagonist of 5-HT2= increased appetite

-potent antagonist of serotonin receptors (5-HT3)= anti nausea/anti-emetic

-antagonist of histamine receptors= sedation

Question 10

Mirtazapine in Cats

Answer 10

-Mirataz 2%- transdermal placed on inner pinna of cats ear

-2mg/cat (4cm strip once daily for 14 days)

-polyphagia observed within 36hrs

Question 11

Mirtazapine pharmacokinetics

Answer 11

-Hepatic metabolism, renal excretion
**need to adjust dose with hepatic or renal disease

-half life= 9-16hrs; some accumulation with repeated doses
**more dose given, longer the half life (RARE/unknown reason)

Question 12

Mirtazapine as an antidepressant in cats

Answer 12

-Owners have observed increased interaction and vocalization… some antidepressant effects

-These side effects are usually seen at higher dose whereas appetite stimulation can be seen at a lower dose

Question 13

Glucocorticoids

Answer 13

Steroids= Polyphagia is a common side effect (and “perking up”)
-seen more in dogs than cats
-usually only transient (days to weeks)
-often used in palliative cases (eg.oncology)

Question 14

Anabolic steroids

Answer 14

Testosterone analogs, suppressing fat and increasing muscle
-related to increased appetite

Question 15

Anabolic steroids in horses

Answer 15

Labeled for use in chronic illness with weight loss, debilitated or androgenic deficient horses
>Testosterone= controlled drugs

*Vet products are now off the market due to drug abuse

Question 16

Benzodiazepines

Answer 16

-diazepam (valium) or oxazepam
-occasionally used as appetite stimulates due to GABA effects and inhibition of hypothalamic satiety center

-seemed to have varying effects with different animals
-superseded by mirtazapine

Question 17

Cyproheptadine

Answer 17

-antihistamine and serotonin receptor blockers which inhibited receptors controlling satiety

-seemed to only work sometimes (“hit or miss”)

Question 18

Capromorelin

Answer 18

-Only in USA
-Ghrelin receptor agonist working at Brain level

-Cats: usually used for chronic kidney dx
-Dogs: general appetite stimulant

Question 19

Cannibinoids and appetite

Answer 19

-no evidence for appetite stimulation in dogs and cats