Drug book Flashcards
Acepromazine
Mechanism of action
Inhibits central dopaminergic receptors for sedation and tranquilization. Antimuscarinic action and blocks norepinephrine at adrenergic receptors (alpha receptors) also causing vasodilation.
Acepromazine
Adverse Effects
Common: sedation, ataxia Rare: extrapyrimidal effects Excessive vagal tone (brachycephalic breeds) Hypotension Horses: persistent penile prolapse
Apomorphine
Mechanism of action
Emetic; potent lipophilic agent that crosses the blood brain barrier to stimulate dopamine receptors in the vomiting center. Not absorbed orally due to first pass effect.
Apomorphine
Adverse Effects
Irritation to the ocular conjunctival membranes.
High doses 0.1mg/kg: sedation.
Higher dose 1mg/kg: excitement
Diphenhydramine
Mechanism of action
Antihistamine: blocks H1 receptor and suppresses inflammation caused by histamine.
Antiemetic: suppresses histamine in emetic, vestibular, and other centers that cause vomitting
Diphenhydramine
Adverse Effects
Common: sedation
Antimuscarinic effects such as dry mouth and dec GI secretions.
High dose: excitement
Famotidine
Mechanism of Action
Antiulcer agent; inhibit histamine on H2 receptors of parietal cells, inhibits gastric parietal cell thus dec gastric acid secretion thus increases stomach pH.
Famotidine
Adverse Effects
Seen with decreased renal clearance: Hemolysis when rapidly injected into cats.
Maropitant
Mechanism of Action
Antiemetic for central and peripheral sources: blocks neurokinin-1 receptor in the emetic center.
Maropitant
Adverse Effects
Slight pain and irritation at SQ injection site.
Excess salivation and muscle tremors.
Metoclopramide
Mechanism of action
Antiemetic: stimulates motility of upper GI, centrally acting antiemetic, stimulate 5-HT4 (serotonin) receptors or increase release of ACH in GI tract, anti-dopamine action in the chemoreceptor trigger zone inhibits gastric relaxation to enhance cholinergic responses of gastric smooth muscle to increase motility, increase tone of esophageal sphincter.
Metoclopramide
Adverse effects
Behavioral changes
Horses: behavioral changes, excitement, abdominal discomfort
Calves: neurologic effects >0.1mg/kg
Misoprostol
Mechanism of action
Synthetic analogue of PGE1 causing a cytoprotective effect on GI mucosa thus decreasing the damage to GI mucosa by NSAIDs.
Anti-inflammatory effects.
Misoprostol
Adverse effects
GI discomfort, vomiting, diarrhea, abortion in pregnant animals
Omeprazole
Mechanism of action
Antiulcer: Increases stomach pH by inhibiting gastric acid secretion by inhibiting K+/H+ pump.
Omeprazole
Adverse effects
Diarrhea
Ondansetron
Mechanism of action
Antiemetic: inhibits serotonin type 3 receptors (5-HT3),
Ondansetron
Adverse effects
None reported
Sucralfate
Mechanism of action
Antiulcer: Gastric mucosa protectant: forms sucrose octasulfate and aluminum hydroxide in the stomach which binds to the damaged mucosa, prevents back diffusion of H+, inactivates pepsin, and absorbs bile acid.
Sucralfate
Adverse effects
No adverse effects.
Human: constipation
Antiemetics
Acepromazine Metoclopramide Maropitant Ondansetron Diphenhydramine
Antiulcer agent
Misoprostol
Omeprazole
Sucralfate
Famotidine
Emetic
Apomorphine
Cisapride
Mechanism of action
Increase GI motility: Agonist for 5-hydroxytryptamine (5-HT4) recetors on myenteric neurons, antagonist for 5-HT3 receptor, enhanses the release of acetylcholine at the myenteric plexus thereby increasing motility of the stomach, SI, and colon.
Cisapride
Adverse effects and Contraindications
Adverse effects: High OD (10mg/kg) abdominal pain, aggression, ataxia, fever, vomiting
Higher OD- diarrhea, ataxia, CNS reactions
Contraindication: GI obstructions
Cisapride
Drug interactions
Atropine: reduced effect
Inhibitors of metabolism or inhibitors of P-glycoprotein: toxicity
Cyproheptadine
MOA
Increase appetite: Alter serotonin activity in the appetite center to increase appetite.
Cyproheptadine
AE
CI
AE: Polyphagia, weight gain, hyperactivity
CI: None
Diazepam
MOA
Increase appetite: Agonist binding of GABA sites in the CNS
Diazepam
AE
CI
AE: sedation, withdrawal syndrome, painful/irritating IM or SQ, phlebitis IV
dogs- ataxia, increased appetite, excitement, agitation
cats- idiopathic fatal hepatic necrosis
CI: impaired liver function, long-term use in cats
Diphenoxylate
MOA
Opiate agonist that bindes to mu-opiate receptors in intestine to stimulate smooth muscle segmentation, decrease peristalsis, enhance fluid and electrolyte absorption
Diphenoxylate
AE
CI
AE: none, possible constipation
CI: diarrhea via infectious causes, chronic treatment of diarrhea
Erythromycin
MOA
Increase GI motility: Stimulation of motilin receptors to increase smooth muscle activity in GI.
Antibacterial: Binds to 50S ribosome and inhibits protein synthesis. Limited to gram + aerobic bacteria and mycoplasma.
Erythromycin
AE
CI
AE: Large animals- diarrhea Foals- hyperthermia Small animals-vomiting, diarrhea CI: orally to rodents or rabbits, IM adminstered IV
Lidocaine
MOA
Local anesthetic: blocks Na channel to inhibit nerve conduction
Antiarrhythmic: lidocaine is metabolised to monoethylglycinexylidide
Analgesic: systemic admin
Decrease ileus: suppress painful stimuli, anti-inflammatory effects on neutrophils
Lidocaine
AE
High dose- tremors, twitches, seizures, vomiting
Cardiac arrhythmias especially on abnormal cardiac tissue
Cats: death from IV, decreased CO, cardiovascular depression, decreased oxygen delivery, methemoglobinemia, hemolysis
Horses IV and CRI caused muscle fasciculations, rapid eye blinking, anxiety, ataxia, weakness, seizures
Lidocaine
CI
Cats are more susceptible to AE, dose dependent
Decreased blood flow to liver can reduce clearance
Loperamide
MOA
Decrease diarrhea: acts on mu-opiate receptors of GI to decrease propulsive intestinal contractions, increase segmentation, increase tone of GI sphincters, decrease secretion into GI, stimulate absorption of fluid, electrolytes, and glucose. Inhibits calcium influx and decreases calmodulin activity.
Loperamide
AE
Sever constipation with repeated use, may cross blood brain barrier in dogs with multidrug resistance gene mutation (Collie, Australian shepherds, old english sheepdogs, longhaired whippets, shetland sheepdogs) to cause profound sedation.
Loperamide
CI
Small dogs and collie-type dogs
Concurrently with MDR1 membrane inhibitors (ketoconazole)
N-butylscopolammonium bromide
MOA
Antimuscarinic: blocks cholinergic receptors to produce parasympatholytic effects thus inhibits secretions and motility of GI.
N-butylscopolammonium bromide
AE
Increased heart rate, decreased secretions, dry mucous membranes, decreased GI motility, dilated pupils
N-butylscopolammonium bromide
CI
Use cautiously where decreased motility of GI will be a concern
Neostigmine
MOA
Inhibits cholinesterase enzyme that breaks down Acetylcholine thus allowing acetylcholine to react longer at the receptor site.
Neostigmine
AE
Diarrhea, increased secretions in GI, miosis, bradycardia, muscle twitching or weakness, constriction of bronchi and ureters
Neostigmine
CI
Urinary or intestinal obstructions, asthma or bronchoconstriction, pneumonia, cardiac arrhythmias, patients sensitive to bromide, don’t use with other cholinergic drugs
Pyridostigmine bromide
MOA
Inhibits cholinesterase enzyme that breaks down Acetylcholine thus allowing acetylcholine to react longer at the receptor site.
Pyridostigmine bromide
AE
Diarrhea, increased secretions in GI, miosis, bradycardia, muscle twitching or weakness, constriction of bronchi and ureters
Pyriostigmine bromide
CI
Urinary or intestinal obstructions, asthma or bronchoconstriction, pneumonia, cardiac arrhythmias, patients sensitive to bromide, don’t use with other cholinergic drugs
Ranitidine
MOA
Antiulcer: blocks H2 receptor suppressing histamine stimulation of gastric parietal cell to decrease gastric acid secretion
Increased GI motility: anticholinesterase action
Ranitidine
AE
CI
AE: only seen with decreased renal clearance
CI: None
Physostigmine
MOA
Inhibits cholinesterase enzyme that breaks down Acetylcholine thus allowing acetylcholine to react longer at the receptor site.
Physostigmine
AE
Diarrhea, increased secretions in GI, miosis, bradycardia, muscle twitching or weakness, constriction of bronchi and ureters
Physostigmine
CI
Do not administer with choline esters (bethanechol)
Altrenogest
MOA
Synthetic progestin hormone that acts as a progesterone angonist to suppress estrus and allow for predictable estrous activity after discontinuation
Drugs to increase GI motility
Cisapride Erythromycine Lidocaine Neostigmine Pyridostigmine Ranitidine Physostigmine
Drugs to Increase appetite
Cyproheptadine
Diazepam
Drugs to decrease diarrhea
Diphenoxylate
Loperamide
N-butylscopolammonium bromide
