Veterinary Pharmacology Part 2 Flashcards
Clomipramine
Amitriptyline
TCA (antidepressants)
NE and serotonin reuptake inhibitor
Sole tx (or combined with anxiolytics) for anxieties/stereotypies
Takes 4-6 weeks before full therapeutic effect
Mild sedation, dry mouth, tachycardia, urinary retention,, constipation, hypotension, arrhythmias, +/- V/D
Fluoxetine, paroxetine, sertraline
SSRI (antidepressants)
Serotonin reuptake inhibitor
Sole tx (or combined with anxiolytics) for anxieties/stereotypies
Takes 4-6 weeks before full therapeutic effect
Mild sedation, GI irritation (V/D, inappetance), excessive vocalization, seizures
Trazodone
SARI (antidepressant)
Serotonin reuptake inhibitor, antagonist at 5HT2, H1 and a1 receptor (low doses), agonist at 5H1 and impacts GABAr
Generally safe in combination with SSRI and TCAs in dogs
3h half life in dogs, 85% bioavailability
Selegiline
MAOi (antidepressant)
Diazepam (and other benzodiazepines)
Benzodiazepines (anxiolytics)
Stabilize/inhibit GABA receptors
Sole tx (or in combination w/ antidepressants) of anxiety
Sedation, ataxia, polyphagia, increased friendliness, excitation, hepatic necrosis
Can interfere with learning/memory
Don’t store in plastic or in light
Buspirone
Azapirones (anxiolytic)
5HT1 partial agonist, dopaminergic effects
Usually sole tx of anxiety, urine spraying - not approved
Multi-cat households
Not sedating, no effect on learning, not CYP mediated
Requires frequent dosing
Decreased inhibition (–> aggression), +/- V, increased affection towards owner, tachycardia
Acepromazine, chlorpromazine, chlorpromazine
Phenothiazines (antipsychotics and anti-emetics)
Dopamine antagonism - inhibits CTZ and/or emetic center
For on-specific sedation, motion sickness?
Poor oral efficacy
Potent, long-acting; hypotension, extrapyramidal signs, mm. rigidity, penile prolapse in horses, ataxia, prolapsed 3rd eyelid, CYP-mediated
Mirtazepine
NaSSA (antidepressant and appetite stimulant)
NE and 5HT1 stimulant
Antagonist of 5HT2 (appetite stimulant) + 5HT3 (anti-nausea/anti-emetic effects), H1 receptors (sedation)
Increased neediness (vocalization/interaction)
Transdermal form
Hepatic metabolism and renal excretion (accumulation?)
Polyphagia within 8-36 hours
Dextromethorphan
NMDA receptor antagonist
Decreased glutamate
Activates sigma receptors (5HT), activates AMPA
Excitatory effects
Reserpine
NE reuptake inhibitor –> NE depletion
Drug of abuse in horses
Significant hypotension
Potentially fatal interactions with other hypotensive drugs (ex. ace)
Dirlotapide
Microsomal triglyceride transfer protein inhibitor
Decreased lipoprotein/chylomicron assembly
More lipid in enterocyte –> satiety signal
Steatorrhea, anorexia, emesis, increase liver enzymes, hepatic lipidosis in cats
Orlistat
Pancreatic lipase inhibitor
Decreased fat digestion/absorption
Like osestra –> diarrhea
Testosterone
Appetite stimulant
Only anabolic steroid approved in vet med
Diazepam
GABA agonist; inhibits satiety center in hypotahlamus
Used in cats
Not terribly effective
Cyproheptadine
Antihistamine + 5HT2 blocker - control satiety
Appetite stimulant in cats
Hit or miss
Megesterol acetate
Synthetic progestin as an appetite stimulant
Significant side-effects (better options out there)
Glucocorticoids (for appetite stimulation)
Transient polyphagia
For palliative cases (ex. oncology)
Inherent activity or “perking up?”
Apomorphine
Emetic in dogs
Give via conjunctiva or IV
Alpha-2-agonists (ex. Dexmedetomidine)
Emetic in cats
Give via IM
Syrup of Ipecac
GI irritaiton –> emesis
Not very effective in vet med
Hydrogen peroxide
Emetic in dogs
Irritation of throat/glossopharyngeal nerve
Not very effective (useful for clients at home)
Antihistamines (as anti-emetics)
Block cholinergic (cats) and histaminic (dogs) nerve transmission responsible for transmission of vestibular stimuli to emetic center Mild sedation
Metaclopromide
Inhibit dopamine in CNS and 5HT3 receptors in CRTZ
Variable PK in small animals but reasonably effective
Peripheral prokinetic effect - increased gastric and upper duodenal emptying + increased GE sphincter tone, through stimulation of 5HT4, dopamine (D2) antagonism
Used for mega-esophagus postop GDV - poor evidence
Extrapyramidal effects (esp. with ace)
Ondansetron
Potent anti-emetics
Serotonin (5HT3) antagonist
Very expensive
Useful during chemotherapy (cytotoxic drugs release serotonin from endochromaffin cells in SI - not as useful for motion sickness-induced vomiting)
Maropitant
Neurokinin (NK1) receptor antagonist: blocks binding of substance P in emetic center - works against SoI and apo
For acute vomiting and motion sickness in dogs
Bone marrow hypoplasia in puppies (<16 weeks)
Can use in cats
Omeprazole
Irreversible inhibition of gastric proton pumps
Very effective for ulcer treatment/prevention - relapse when off therapy
Can lead to hypergastrinemia –> hyperplasia/hypertrophy and carcinoids
CYP enzyme inhibitor
Wean off after prolonged use (>3-4 weeks) - risk of hyperacid rebound syndrome)
Cimetidine, famotidine, ranitidine
H2 receptor antagonists
Limited evidence of efficacy in dogs/cats (Omeprazole is better) - none licensed for vet use
Ranitidine and cimetidine may be prokinetic
Low bioavailability in horses/ruminants; lipid-soluble
Cimetidine inhibits CYP enzymes
Antacids
Neutralize stomach acid to form water and salt
Short-term fix, cheap
Sucralfate
Dissociates to sucrose octasulfate (coats ulcer) and aluminum oxide
Increases mucosal PGE synthesis
Few ADRs, cheap, easy to administer
No good evidence
Misoprostal
Synthetic PGE analogue - stimulates bicarb and mucus secretion, increases blood flow, decreases vascular permeability, increases cell proliferation/migration
Use as preventative for NSAID or steroid-induced ulcers in dogs
Few ADR, but limited evidence of efficacy
Domperidone
Poor GI prokinetic effect
Dopamine antagonist (like metaclopramide)
No CNS reactions
Treatment of agalactia (stimulate prolactin secretion)
Cisapride
5HT4 agonist (increased ACh in myenteric neurons) and 5HT3 antagonist (like metaclopramide) More effective than metaclopramide Increase smooth muscle motility in stomach, small intestine and colon - used for megacolon in cats, for dogs throughout GIT, and for horses to treat postop ileus Shorter half-life in dogs and cats than horses/ruminants Arrhythmias and CYP interactions in humans
Erythromycin
Macrolide antimicrobial
Activates motilin receptors in stomach and proximal SI
Can cause vomiting and regurgitation (direct irritation?)
Can cause diarrhea in horses (GI flora disturbance)