Antimicrobials CHAPTER 10-2 Dr. Dipa Brahmbhatt VMD MpH [email protected].
Chapter 11 Gastrointestinal Drugs Dr. Dipa Brahmbhatt VMD MpH [email protected].
-
Upload
miranda-cain -
Category
Documents
-
view
232 -
download
4
Transcript of Chapter 11 Gastrointestinal Drugs Dr. Dipa Brahmbhatt VMD MpH [email protected].
Chapter 11 Gastrointestinal Drugs
Dr. Dipa Brahmbhatt VMD MpHDr. Dipa Brahmbhatt VMD [email protected]@vettechinstitute.edu
Emetics
• Emetics (don’t use in unconcious/seizuring/compromised animal)
– Drugs that induce vomiting
– Used in the treatment of poisoning and drug overdose
– Vomiting should not be induced if caustic substances have been ingested (Ammonia, lye, bleach)• Always check with poison control prior to inducing vomiting
– Can be centrally acting (working on the CRTZ) or peripherally acting (working on receptors locally)
Emetics
Centrally acting• Apomorphine (Apokyn)
– Choice for Dogs– Stimulates dopamine receptors in CRTZ– Morphine derived emetic– Peripherally: SQ/IM: vomit in 5-10 minutes– Subconjunctivally: Conjunctiva sac: vomit in 10 – 20 minutes– SE: Protracted vomiting, CNS depression and restlessness
• Xylazine– Choice for cats– SE: bradycardia, decreased respiratory rate
Inducing Emesis
Apomorphine
Xylazine
Emetics
Peripherally acting• Ipecac syrup
– 2 alkaloids: emetine & cephaelineIrritate gastric mucosa and stimulateCRTZ– Stomach and SI evacuated: 10-30 mins– SE: Higher doses cause CV problems
• Home remedies– Hydrogen peroxide– Salt and water/ mustard and water/ salt followed by water– Less reliable than other emetics
Emetics
• Activated charcoal is given if emesis is contraindicated
• It absorbs many chemicals and drugs in the upper GI tract
• Liquid/ Powder form (reconstituted with water)
• SE: Constipation, diarrhea and blackening of feces
• Superchan, Vet Powder, Vet Liquid, Toxiban (activated charcoal and kaolin)
Ulcers
• Ulcer: erosions of mucosa– Causes: metabolic disease, drug therapy & stress
– C.S.: Anorexia, melena, abdominal pain, and hematemesis
– Protected by • Mucus which protects mucosa from gastric secretions
• Sphincter muscles: cardiac and pyloric prevent reflux of acid to esophagus and duodenum
↑ release of HCL from parietal cells - stomach
Activated byHistamineGastrinAcetylcholine
AntacidSystemic: sodium bicarbonate, calcium carbonateNonsystemic: magnesium hydroxide, aluminum/magnesium hydroxide, aluminum hydroxide
Cimetidine (Tagament®)Ranitidine (Zantac®)Famotidine (Pepcid®)
Sucralfate
Misoprostol
OmeprazoleLansoprazole
Antiulcer Drugs
• Antiulcer drugs– Help prevent the formation of ulcers
– Categories include• Antacids
• Histamine-2 receptor antagonists
• Mucosal protective drugs
• Prostaglandin analogs
• Proton pump inhibitors
Antiulcer Drugs
• Antacids• Promote ulcer healing by neutralizing
HCl and reducing pepsin activity• Rapid onset and short duration of action• Interact with other drugs–By adsorption or binding the other drugs–By increasing stomach pH (decrease of absorption
of certain drugs)–By increasing urinary pH (inhibit elimination of
weak bases)
Antiulcer Drugs
• Antacids• May be systemic or nonsystemic• Examples:
– Systemic (in blood): sodium bicarbonate, calcium carbonate
– Nonsystemic (in GI): » Magnesium hydroxide: milk of magnesia, given to
cows to treat rumen acidosis (increases rumen pH)» Aluminum/magnesium hydroxide, aluminum
hydroxide: Mylanta used in foals and dogs in adjunct treatment for ulcer
» Aluminium hydroxide: Amphojel lowers phospahte levels
Antiulcer Drugs
• Histamine-2 receptor antagonists• Prevent acid reflux by competitively blocking the H2 receptors of
the parietal cells in the stomach, thus reducing gastric acid secretion
• SE: rare, diarrhea and inhibition of liver enzymes• Examples:
– Cimetidine (Tagament®)– Ranitidine (Zantac®)– Famotidine (Pepcid®)
Most potent Fewer SE than zantacLess bioavailable
More potent than tagamet Longer duration of actionThan tagamet
Antiulcer Drugs
Mucosal protective drugs Combine with protein to form an adherent
substance that covers the ulcer and protects it from stomach acid and pepsin
An example is sucralfate SE: Constipation Don’t give with H2 receptor antagonist
Mucosal protective drugs Combine with protein to form an adherent
substance that covers the ulcer and protects it from stomach acid and pepsin
An example is sucralfate SE: Constipation Don’t give with H2 receptor antagonist
Antiulcer Drugs
• Prostaglandin analogs• Suppress gastric secretions and increase mucus production in the
GI tract• An example is misoprostol, which is usually given to animals
taking NSAIDs• Pregnant women need to be careful while handling• SE: GI: diarrhea, vomiting, abdominal pain
• Proton pump inhibitors• Bind irreversibly to the H+-K+-ATPase enzyme on the surface of
parietal cells of the stomach; this inhibits hydrogen ion transport into the stomach so that it cannot secrete HCl
• Examples:– Omeprazole (gastroguard)– Lansoprazole
Antiulcer Drugs
• Omeprazole
– Horses and foals > 4 wks of age
– Heal gastric ulcer and prevent
re-occurrence
• Causes: feeding problems (less hay)
• Intensive training
• Development/growth
• Lansoprazole (Prevacid)
– Used to tx. Gastroesophageal reflux and ulcers
– Extra lable
BLOAT•Foamy/pasture/legume•Rumen is distended•Asphyxiate the animals
Antifoaming Agents
– Reduce or prevent the formation of foam
– Used in ruminants, whose rumens are subject to acute frothy bloat
– Make this foam less stable, breaking it up to promote gas release through belching
– Administered as solutions by stomach tube directly into the forestomach
– Examples include poloxalene and polymerized methyl silicone
Motility Enhancing
• Prokinetic agents– Increase the motility of parts of the GI tract to enhance
movement of material through it
– Types of prokinetic agents are:• parasympathomimetics• dopaminergic antagonists• serotonergic agents
Prokinetic Agents
• Parasympathomimetic agents include
– Acetylcholinesterase inhibitors, which compete with ACh for acetylcholinesterase, resulting in increased intestinal tone and salivation• An example is neostigmine• Tx of rumen atony and to diagnose
myasthenia gravis in dogs• SE: Vomiting diarrhea and increased
salivation
– Cholinergics, which make a precursor to acetylcholine• An example is dexpanthenol
Prokinetic Agents
• Dopaminergic agents stimulate gastroesophageal sphincter, stomach, and intestinal motility by sensitizing tissues to the action of the neurotransmitter ACh
• Examples include metoclopramide and domeridone• Don’t use reglan with antichlinergic drugs
• Serotonergic agents stimulate motility of the gastroesophageal sphincter, stomach, small intestine, and colon
• An example is cisapride
Enzyme Supplements
– Pancreatic enzymes must be supplemented in the diet when the pancreas is not functioning properly (as in pancreatic exocrine insufficiency)
– Pancrealipase contains primarily lipase, but also contains amylase and protease
– Can be irritating to the skin on contact and to nasal passages upon inhalation
Appetite-Stimulating Drugs
• Serotonin antagonist antihistamines– Promote appetite by inhibition at the serotoninergic receptors
which control satiety
– Side effects include sedation and dry mouth
• Benzodiazepines– Effective appetite stimulants in cats but not dogs
– Side effects include sedation and ataxia
• Tetracyclic antidepressants– Stimulate appetite by antagonizing alpha2-receptors
– Side effects include sedation, vocalization
Appetite Stimulating Drugs
• Glucocorticoids– Stimulate steroid-induced euphoria which stimulates
appetite
– Side effects include polydipsia, polyuria, dull haircoat, weight gain, and behavioral changes
• Anabolic steroids– Stimulate hematopoiesis, appetite, and weight gain
– Side effects include hepatotoxicity, masculinization, and early closure of growth plate in young animals
Appetite Stimulating Drugs
• Progestins– Used to stimulate appetite and promote weight gain in
anorectic cats and dogs
– Side effects include behavioral changes, endometritis, and mammary enlargement
Appetite Suppression
• Dirlotapide (Slentrol®)– Drug for management of obesity in dogs
– Side effects include vomiting, diarrhea, lethargy, and anorexia
Dental prophylaxis