MOA: A quarternary ammonium compound that DOES NOT cross into the CNS but has antimuscarinic effects that inhibits the acetylcholine at the post ganglionic parasympathetic neuroeffector organ.

Uses: treatment of bradycardia during anesthesia, premedication to counteract bradycardic effects of other anesthetic agents or adjuncts, other indication that would be treated by use of an anticholinergic

Side effects: Dose related - dry secretions, initial bradycaardia then tachycardia (often not as pronounced as the effect of atropine on this side effect) glowing of the GI tract, urinary obstruction

Dosage forms: Oral and injectable forms available

Notes: should not be used in patients with urinary obstructive diseas, Gastrointestinal ileus, narrow angle glaucoma or tachyarrhythmias

Trade name: none

MOA: Amn antimuscarinic that completely inhapits acetycholine at the postganglionic parasympathetic neuroeffector sites

Uses: Various indications but for this topic - reduction in saliva production

Side effects: dry secretations (in ruminants can cause asphyxiation), initial bradycardia then tachycardia (may be profound) sluggish GI (reduces peristalsis) urinary retention, pupillary dilation

Dosage forms: injectable

Note: this drug is capable of crossing the blood brain barrier and directly affecting the central nervous system

Drugs that decrease peristalsis, thereby allowing increased fluid absorption from the inestinal contents

Anticholinergics - this is NOT a common use for this class of drug, Protectant/adsorbents, Opiate - related agents,Probiotics, Metronidazone

Notes: used to treat tenesmus and vomiting.

Examples of anticholinergics used as anti-diarrheals

Trade Name: centrine

MOA: An antimuscarinic that inhabits acetycholine at the postganglionic parasympathetic neuroeffector sites

Uses: various indications but for this topic - reduction in the tone and amplitude of colonic contractions to a greater degree and for a more extended period than does atropine

Side effects: dry secretations (in ruminants can cause asphyxiation), initial bradycardia then tachycardia (may be profound) sluggish GI (reduces peristalsis) urinary retention, pupillary dilation

Dosage forms: injectable

Notes: Mydriatic and salivary effects are less than those produced by atropine at similar dosage, permittiong the control of vomiting and diarrhea with less distress to the animal due to dryness of the mouth and blurred vision

Is an example of Antidiarrheal Drugs and has no information regarding it

Trade name: Probanthine

MOA: blocks acetylcholine at the GI smooth muscle most notably the colon to reduce colonic spasm

Side effects: dry secretions (in ruminants can cause asphyxiation), initial brady cardia then tachycardia (may be profound) sluggish GI (reduices peristalsis) urinary retention,pupillary dilation

Uses: treatment of spasmodic colitis in horses (colic) and to reduce muscle tone in the colon for rectal palaption

Notes: contraindicated in cases of tympanic colic in horses

Trade Name: Biosol - M

MOA: antispasmodic effects of the anticholinergic combined with Neomycin Sulfate (aminoglycoside antibiotic) to control GI flora

Uses: most often used as an enema

General MOA - coat inflamed intestinal mucosa with a protective layer (protectants) and bind bacteria and/or digestive enzymes/toxins to protect the intestinal mucosa from damaging effects (adsorbents)

Trade Name: Pepto-Bismol

MOA: bismuth coats the upper GI tract to protect it. May also be weakly antibacterial. Subsalicylate is an aspirin like compound that reduces prostaglandins for an anti-inflammatory effect

Uses: treatment of diarrhea and treatment of H. pylori infections

Notes: cats are very sensitive to the aspirin like compoujnd and can experience significant toxicity. Dogs may develop gastric erosion secondary to the aspirin like compound and they may develop black stools as a result. The history of an owner administering this compound is important because it will limit what your veterinarian can prescribe for analgesia if needed. Refrigeration may improve palatability. Should not be used in place of adequate supportive therapy.

Trade Name: KaoPectate

MOA: presumably, bacteria and toxins are adsorbed in the GI tract and the coating action may quiet inflamed mucosa. The pectin component will decrease the pH in the intestinal lumen

Indications: adjunctive treatment of diarrhea or adsorption of certain toxins

Side effects: not systemically absorbed, side effects rare - constipation

Notes: efficacy not documented. Not best choice for adsorption of toxins. Not a substitute for proper supportive care. Large volumes of drug may be required for adequate treatment

Control diarrhea - decreasing intestinal secretions, decreasing the flow of feces, increasing segmental contractions

Examples: Diphenoxylate, Loperamide, Paregoric

Trade name: Lomotil

MOA: inhibits GI motility and excessive GI propulsion. May enhance GI mucosal absorption

Use: opiate combined with atropine to treat diarrhea in dogs by altering GI motility

Side effects: constipation, bloat, sedation

Notes: Use with caution in cats and small dogs. Use with caution in patients with toxic causes of diarrhea (retention may occur). Class V controlled substance contains a small amount of atropine as well

Trade Name Immodium AD

MOA: Opiate drug used to treat diarrhea by altering GI motility

Use: used to treat diarrhea in dogs by slowing GI movement

Side Effects: constipation, bloat, sedation in dogs. Can cause paralytic ileus, toxic megacolon and pancreatitis

Notes: available OTC as a human preparation Not for use in cats, can vause excitation. Generally speaking, antidiarrheal medication is not for use in cats

Trade Name: camphor tincture of opium

MOA: inhibits GI motility and excessive gi propulsion to control diarrhea in small animals

Use: antidiarrheal agent effective by slowing GI motility in general

Side effects: DOGS: constipation, bloat, sedation, CATS: excitation HORSES: prolonged febrile state from bacterial enteritis

Notes: Class III controlled substance, morphine is the opioid in the drug. Dose should be carefully calculated to avoid adverse effects. May cause excitation in cats. Stopping toxic or infectious diarrhea may prolong effects of disease or be contraindicated

MOA: seed the GI tract with beneficial bacteria

Use: the use is based on the theory that some forms of diarrhea are caused by disruption of the normal bacterial flora of the GI tract

Side Effects: none with veterinary preparations. Occasionally owners will try to use yogurt or human preparations and we occasionally see GI upset with those

Trade Name: flagyl

MOA: effective against ANAEROBIC bacteria - taken up by the bacteria where it interferes with DNA/nucleic acid synthesis

Use: treatment of anarobic infections (enteric and otherwise) in animals, treatment of giardia.in dogs (and cats) - must be compounded to be used safely in small dogs and cats

Side Effects: Neurologc effects, lethargy, weakness, +/- hepatotoxicity, anorexia, vomiting, diarrhea. The neurologic effects seem to be related to high dosages over several days (comulative effects)

Notes: Prohibited for use in food producing animals

Trade Name: Cephulac

MOA: A disaccharide not hydrolysable in the mammalian gut - makes it to colon where bacteria beak it down

Trade name: Fleet Enema

MOA: draws water into the colon to increase fecal bulk and stimulate passage of stool

Notes: TOXIC TO CATS

General MOA: increase peristalsis bu chemically irritating sensory nerve endings in the intestinal mucosa, many of these are absorbed systemically and cause a variety of side effects

Trade Name: Dulcolax

MOA: a cathatrtic thought to function by increasing peristalsis while increasing fluid buildup in the colon

Minor - just wanted you to know classification

MOA: ricinoleic acid is liberated into the small intestine to injhabit water and electrolyte absorption leading to fluid accumulation in the GI tract which leads to increased peristalsis

Notes: Can cause massive irritation to the lining of the upper GI

General Functions: absorb water into the intestine, increase fecal bulk, and stimulate peristalsis for a net result of large, soft stool production

Trade Name: Metamucil, Equine Psyllium, Perdiem

MOA: increase fecal water content thereby increasing fecal bulk. This puts pressure on the walls of the colon and results in evacuation of the colon

Side Effects: GI cramping and flatulence

Trade Name: FiberCon, Fiberall

MOA: increase fecal water content thereby increasing fecal bulk. This puts pressure on the walls of the colon and results in evacuation of the colon.

Notes: Dose adjustment mayu be required for optimum results

Stool softeners - work by reducing stool surface tension. Also hold water into the colon

Lubricamnts - facilitate the passage of fecal material. This also increases water retention in the stool.

Also known as fecal wetting agents. These are detergent-like drugs that permit easier passage of feces - this is accomplished by mixing fats and fluid with the fecal mass

Trade Names: Docusate Sodum (Colace), Docusate Calcium (Surfake), Docusate Potassium (Dialose)

MOA: Emollients to soften stool and ease passage

Use: soften stools

Notes: dose adjustment may be required for optimum results

Trade Name: Mineral Oil, Laxatone

Notes: can cause linear erosion in the GI tract of some patients

Antihistamines, Anticholinergics, Procainamide, Serotonin, Neurokinin

Trade Name: Tigan

MOA: thought to be active at the Dopaminergic receptors at the CRTZ

Use: treatment of emesis

Trade Name: Dramamine

MOA: blocks histamine - thought to work best for motion sickness

Use: treatment of motion sickness

Trade Name: Benadryl

MOA: Blocks the histamine receptors

Use: treatment of nausea associated with motion sickness

Trade name: Dramamine Non-Drowsy

MOA: blocks histamine - works best for motion sickness

Uses: treatment of nausea and motion sickness related to vestibular disease

Not a strong anti-emetic will have mild antiemetic properties by decreasing intestinal motility and secretion (recall it does this through Acetylcholine blockade)

Due to slowing of GI motility this drug may actually decrase stomach emptying and cause an increase cause of vomiting.

Examples: (all of these drugs are covered elsewhere - please see other outlines) Animopentamide, Atropine, Propantheline

Trade Name: Reglan

Side effects - Dry mouth constipation, urinary retention, tachycardia

MOA: work centrally by blocking the CrtZ and peripherally by speeding gastric emptying, strengthening cardiac sphincter tone, and increasing the force of gastric contraction

Use: treatment of gastric stasis, esophageal reflux, general anti-emetic

Side effects: DOGS constipation, behavior changes, CATS: frenzied behavior or disorientation, constipation HORSE: severe CNS effects, behavior changes, abdominal pain FOALS: adverse effects less common

Notes: should not be used in animals with GI obstructions, GI perforation , or GI hemorrhage, often used postoperatively to stimulate normal GI movement and prevent vomiting

Trade name: Ondansetron, Dolasetron (Anzemet)

MOA: work selectively on 5-HT3 receptors, which are located peripherally and centrally; work on the theory that some chemicals cause vomiting because they increaseserotonin release from small intestinal cells

Trade name: Zofran

MOA: 5-HT3 receptor antagonist - these receptors are found on the vagus nerve terminals and the CRTZ - may act centrally, peripherally or both

Use: antiemetic when other antiemetics are not effective. Often used in oncology patients

side effects: constipation, occasionally arrhythmias noted (human), hypotension possible

Trade Name: Cerenia

MOA: work on NK1 receptors located in the center of the brain work by inhibiting substance P (neurotransmitter involved in vomiting)

Uses: to prevent acute vomiting and motion sickness

Side effects include: Pain at the injection site, pre-travel vomiting, Hypersalivation, diarrhea

Notes: keep in fridge, stings with injection

Help prevent the formation of ulcers

Promote ulcer healing by neutralizing HCI and reducing pepsin activity

Interact with other drugs

May be systemic or non-systemic

Categories include; antacids

By adsorption or binding the other drugs

By increasing stomach pH

By increasing urinary pH

Absorbed systemically and will cause side effects

Examples: Sodium bicarbonate, calcium carbonates

Not absorbed - will exert action only in the gut where they are put. Examples: magnesium hydroxide, aluminum/magnesium hydroxide, aluminum hydroxide

Trade name: TUMs

MOA: neutralizes acid in the stomach by donating the biarbobnate buffer. Calcium is systemically absorbed

Use: more commonly used as a calcium supplement in dogs that have had parathyroid hormone removal or require additional calcium for other systemic disease

Side effects: hypercalcemia vomiting, constipation

Notes: available over the counter. Also used as a supplement for pregnant bitches or during lactation

Trade Name: Milk of Magnesia

MOA: hydroxide neutralizes acid in the stomach

Side effects: constipation (calcium agents) diarrhea (magnesium agents), electrolyte imbalances

Notes: Used in cattle for raising rumen pH and treatment rumen acidosis (grain overload). Contraindicated in animals with renal disease - will lead to electrolyte disturbances

Trade Name - Amphogel

MOA: reduces the dietary absorption of phosphorus by binding to the phosphorus in the gut

Side effects: constipation. Not systemically absorbed

Notes: administration of AL-OH to a patient that is not eating is nonproductive. Used often in renal failure patients to absorb phosphorus from the diet and prevent absorption. This helps prevent hyperphosphatemia a common problem with patients with renal insufficiency. Should be given with food.

Prevent acid reflux by competitively blocking the H2 receptors of the parietal cells in the stomach reducing gastric acid secretion.

Recall normal physiology where histamine binds to H2 receptors and then causes hydrogen ions and chloride ions to be separately released into the lumen of the stomach - once there, they find each other and form an ionic bond (HCI) produced. The pH of HCI is around 2!!

Trade name: Tagamet

MOA: competitive inhibition at the H2 receptors to prevent histamine. This reduces gastric acid output (when food is present or not)

use: treatment and prophylaxis of gastric, abomasal and duodenal ulceration. Uremic gastritis, esophagitis and esophageal reflux

Side effects: rare at recommended dosages. Can inhibit cytochrome P450 in the liver thus altering the metabolic rates of other drugs

Notes: newer H2 blockers may have fewer drug interactions and longer duration of activity than Cimetidine

Trade Name: Zantac

MOA: competitive inhibition at the H2 receptors to prevent histamine. This reduces gastric acid output (when food is present or not).

Use: used to reduce acid output n stomach. Has mild pro-kinetic effects.

Notes: use with caution in severely debilitated animals. Longer duration of action, more potent than Cimetidine

Trade Name: Pepcid

MOA: at H2 receptors of parietal cells, provides competitive inhibition of histamine reducing gastric acid production. Does not alter gastric emptying or bile secretion/gall bladder emptying

Use: reduce GI acid production

Side Effects: to rapid IV infusion may cause bradycardia, can cause intravascular hemolysis when given IV to cats

Notes: use with caution in debilitated patients, can be given IV in cats, there have been anecdotal reports of hemolysis - thought to be an idiosyncratic reaction. Safer to give SQ in cats - can be given SID for SQ injection

General action is to combine with protein to form an adherent substances that covers the ulcer and protects it from stomach acid and pepsin. Exaample: Sucralfate

Trade name: Carafate

MOA: reaction with HCI to form a ;paste that will adhere to ulcerated mucosa (binds to the proteinaceous compounds present at the damage site)

Forms a band-aid

Use: protection of GI, esophageal, duodenal and oral ulceration

Side effects: uncommon, constipation has been reported

Notes; should be given at least 1 hour before other medications and food. Requires an acid environment to work - stagger administration of antacids

suppress gastric secretions

Increase mucus production in the GI tract

Trade Name: Cytotec

MOA: inhibits basal and nocturnal gastric acid secretion by parietal cells. Cytoprotective effects on the gastric mucosa

This drug is a Prostaglandin E1 Analog

Use: prevention of gastric ulceration caused by NSAID administration (or overdose)

Side Effects: diarrhea, abdominal pain, vomiting, flatulence. Potentially cause uterine contractions and vaginal bleeding in intact female dogs

Notes: contraindicated in pregnant or nursing animals. Female staff and owners should wear gloves when handling. CAN CAUSE TERMINATION OF PREGNANCY IN EITHER THE PATIENT OR IN THE OWNER HANDLING THE DRUG

General mechanism is (a) Bind irreversibly to the H+-K+-ATPase enzyme on the surface of parietal cells of the stomach (b) This inhabits hydrogen ion transport into the stomach so that it cannot secrete HCI

Trade Name: Prilosec, Gastrogard

MOA: In an acid environment, it binds (irreversibly) to the secretory surface of parietal cells - hydrogen ions cannot be pumped into the stomach. (inhibits Cytochrome P450)

Uses: treatment of gastroduodenal ulcers, treatment of prevention of gastric erosions from ulcerogenic drugs (IE Aspirin)

Side Effects: use caution in debilitated animals HORSES: unlikely problems, SMALL ANIMALS: anorexia, abdominal pain, nausea, vomiting, flatulence, diarrhea

Notes: pantoprazole is an injectable proton pump inhibitor that can be used in a similar fashion if injectable PPI is required.

Examples are Omeprazole and Lansoprazole (no info on this one)

Reduce or prevent the formation of foam in cases of frothy bloat in the ruminant. Used in ruminants, whose rumens are subject to acute frothy bloat

How it works: Make this foam less stable, breaking it up to promote gas release through belching (eructation). Administered as solutions by stomach tube directly into the forestomach

Example: Poloxalene and Polymerized methyl silicone

Increase the motility of parts of the GI tract to enhance movement of material through it.

Types of agents 1. Parasympathomimetics 2. Dopaminergic antagonists 3. Serotonergic agents

Acetylcholinesterase inhibitors - general MOA compete with ACh for acetylcholinesterase

Acetylcholinesterase inhibitors - General effects (1) increased intestinal tome (2) increased salivation

Acetylcholinesterase inhibitors - An example is neostigmine (this drug will be discussed in the muscle section)

Cholinergics general MOA is that they make a precursor to acetylcholine

Cholinergics - an example is dexpanthenol

an agent is dexpanthenol

General actions: Stimulate GI tract sphincter

MOA: Intestinal motility by sensitizing tissues to the action of the neurotransmitter ACh

Examples: Metoclopramide - discussed earlier in this outline

Domeridone

Serotonergic agents general actions - stimulate motility of the GI track sphincter. An example if cisapride

Pancreatic enzhmes must be supplemented in the diet when the pancreas is not functioning properly - Exocrine pancreatic Insufficency (EPI) - commonly in GSD. Pancrealipase coontains primarily lipase, but also contains amylase and protease

Can be irritating to the skin on contact and to nasal passages upon inhalation - wear gloves when using and mix with wet food or soak in water. Examples Pancreazyme, Viokase V

Serotonin Stimulant Drugs

Benzodiazepines

Tetracyclic antidepressants

Glucocorticoids

Anabolic steroids

Progestins

Weight loss drugs

Promote appetite by inhibition at the serotoninergic receptors which control satiety..side effects; sedation, dry mouth. An example is Chlorphreneramine

Effective appetite stimulants in cats but not dogs

Oral administration of benzodiazepines (specifically Valium) for more than 4-5 days has an increased risk of hepatic failure (can be idiosyncratic)

Side effects are sedation, ataxia

Examples are Valium, Midazolam

General MOA: stimulate appetite by antagonizing alpha2-receptors. Side effects are sedation and Vocalization

Stimulate steroid-induced euphoria which stimulates appetite

Only used in terminal cases where the owner would like to try one last time to improve quality of life. Must be discussed with owners as this is truly a risk-benefit ratio that is not often favorable Also, side effects are often intolerable to the owner

Side effects (point: these are similar to the clinical signs of Cushing's disease because we are providing the excess corticosteroids...) 1. Polydipsia (compensatory) 2. Polyuria (primary problem - often the most concerning side effect to owners.) 3. Dull hair coat 4. Weight gain 5. Behavioral changes

Not commonly used in small animal medicine - most common application would be improved feed conversion in food producing animals

Actions: stimulate 1. Hematopoiesis 2. Appetite 3. Weight gain. Side effects: 1. Hepatotoxicity 2. Masculinizaion 3. Early closure of growth plate in young animals

Used to stimulate appetite and promote weight gain anorectic cats and dogs (although there are other drugs available now). Side effects: Behavioral change, Endometritis, Mammary elargement

Drug for management of obesity in dogs. Side effects: vomitiing, diarrhea, lethargy, anorexia

Client education about calorie restriction, proper treat administration and exercise is a better way to approach weight loss in our dogs and cats