Gastrointestinal Drugs and Food PDF

Gastrointestinal Drugs and Food Review of Gastrointestinal System The gastrointestinal system starts with the mouth and ends at the anus. It is a long, tube-shaped organ system whose purpose is to break down food (digestion) and absorb the nutrients needed for an animal’s survival. The basic layout...

Gastrointestinal Drugs and Food Review of Gastrointestinal System The gastrointestinal system starts with the mouth and ends at the anus. It is a long, tube-shaped organ system whose purpose is to break down food (digestion) and absorb the nutrients needed for an animal’s survival. The basic layout of the gastrointestinal system is shown in the images below. Most species have a simple stomach that consists of one outpouching in the gastrointestinal tract. This simple stomach is lined by mucosa that contains goblet cells that secrete mucosa to protect the cells of the stomach. Ruminants and camelids have a complex stomach that consists of four “chambers” designed to aid in breaking down complex carbohydrates through bacteria fermentation. The three orad chambers are the rumen, reticulum, and omasum. Once bacterial carbohydrate fermentation is sufficient, the ingesta passes into the abomasum, which serves the same function as the simple stomach in other animals. The equine stomach is unique because the orad portion is covered in non-glandular squamous mucosa, while the aboral 2/3 of the stomach is covered in secretory glandular mucosa. Digestion occurs in two major ways: mechanical and chemical. Mechanical digestion initially occurs in the oral cavity through mastication. This is when food is ground into smaller pieces using the molars. The tongue mixes the food with saliva. Animals that are herbivores and omnivores secrete amylase in their saliva, starting the chemical digestion of carbohydrates. True carnivores eat primarily meat and do not chew their food very much. Carnivores do not secrete any amylase in their saliva. Once the food has been prepared in the oral cavity, it is moved to the back of the mouth and swallowed. It then travels through the esophagus via peristalsis and gravity. Upon arrival in the stomach, chemical digestion occurs in all species. In animals with a simple stomach, hydrochloric acid is secreted by parietal cells in the glandular mucosa. This binds with protein in the diet, starting the chemical breakdown into smaller proteins and amino acids for later absorption. In ruminants, the complex carbohydrates such as cellulose are circulated through the rumen and reticulum so the bacterial colony in the forestomachs can start digesting them through fermentation. This ingesta is regurgitated and chewed again to complete more mechanical digestion and facilitate fermentation. Once fermentation and carbohydrate breakdown is well along, the ingesta moves through the omasum to the abomasum, where hydrochloric acid starts digesting the protein. After chemical and some mechanical digestion in the stomach, the food passes through the pyloric sphincter into the duodenum. This is now called chyme. The presence of food in the duodenum triggers the release of pancreatic enzymes called amylase and lipase. These travel through the pancreatic ducts to either the common bile duct or to the lesser duodenal papilla. The presence of fats in the duodenum causes gall bladder contraction, resulting in bile moving into the bile duct. The common bile duct releases the bile into the lumen of the duodenum at the major duodenal papilla. The bile breaks down larger pieces of fat into smaller lipid droplets. The amylase starts carbohydrate digestion in carnivore and continues it in other animals. The lipase breaks down the smaller fat droplets into their constituent fatty acids for absorption. By the time the chyme reaches the jejunum, all three main food components are mechanically and chemically digested. Once the chyme moves into the jejunum, the process of absorption occurs. The jejunal mucosa is folded into villi and the mucosal cells’ membranes are folded into microvilli. This adaptation significantly increases the surface area and allows for increased absorptive capacity. Once nutrients are absorbed in the jejunum, the chyme passes into the ileum, which serves to connect the small intestine to the large intestine. At the junction of the small intestine and large intestine there is an outpouching of the intestinal tract called the cecum. In most animals, the cecum is simply an additional location for water absorption. However, in equids the cecum is used for carbohydrate fermentation, a process that continues into the large colon. In most animals, the large intestine consists of an ascending colon, transverse colon, a descending colon, and the rectum. The function of the large intestine is primarily water absorption and storage of fecal matter. It also functions to secrete bicarbonate, participating in regulating acid base balance. Once feces is accumulated, defecation is triggered and the feces passes through the anal sphincter to exit the body. In equids, the large intestine is specialized to work with the cecum and accomplish complex carbohydrate digestion. The first part of the large intestine is called the large colon. This consists of the right ventral colon, sternal flexure, left ventral colon, pelvic flexure, left dorsal colon, diaphragmatic flexure, and finally the right dorsal colon. Once the carbohydrates are appropriately broken down through bacterial fermentation, the resulting volatile fatty acids are absorbed in the cecum and colon. These VFAs provide energy for the horse. The small colon is primarily responsible for water absorption from the fecal matter, while the rectum stores feces for later defecation. The colon is also important in regulating bicarbonate levels. Two types of contraction occur in the gastrointestinal system: peristalsis and segmentation. Peristalsis consists of rhythmic waves of longitudinal muscle contraction that move the ingesta and chyme through the digestive tract. Segmentation is contraction of the circular muscles in the intestinal tract designed to break the chyme into smaller portions, allowing for better nutrient absorption. The functions of the gastrointestinal tract are regulated by the autonomic nervous system as well as both endocrine and paracrine hormones. The nervous system triggers increased hormone and secretions when an animal begins to masticate food. The hormones increase gastrointestinal tract activity by stimulating digestive functions. Gastrin from the stomach increases hydrochloric acid secretion when ingesta arrives in the stomach. Cholecystokinin from duodenum triggers gall bladder contraction and pancreatic enzyme release. The vagus nerve is the sensory branch of the parasympathetic system in the gastrointestinal tract. It detects stretch of the gastric wall and triggers peristaltic movement, pushing the now liquefied food into the duodenum. More information about regulation of the gastrointestinal tract is found on these websites: https://vetericyn.com/blog/the-dog-digestive-system/ https://gpb.pbslearningmedia.org/resource/nat08.living.str.living.digest/nature- holy-cow-a-cows-digestive-system/ https://www.youtube.com/watch?v=8lqk7igz9L4 http://users.atw.hu/blp6/BLP6/HTML/C0269780323045827.htm When discussing gastrointestinal symptoms with owners, it is vital to differentiate between vomiting and regurgitation. Regurgitation is a passive process that occurs when food stuck in the esophagus is moved orally through a change in thoracic pressure. It typically occurs when an animal moves, and the regurgitated material tends to remain in a tubular shape. Vomiting, on the other hand, is a process controlled by the chemoreceptor trigger zone in the medulla, vomiting center in the medulla, vestibular system in the inner ear, or through direct gastrointestinal stimulation. Once one of these mechanisms is triggered, the neurologic signal for vomiting occurs. Vomiting involves active reverse contraction of the stomach and esophagus in as well as engagement of the abdominal muscles. Emetics Emetics are drugs used to induce vomiting (emesis). They are either centrally acting in the chemoreceptor trigger zone or peripherally acting by direct mucosal irritation. Syrup of Ipecac is NOT standard of care due to side effects and is no longer recommended in veterinary medicine. The commonly used emetics are ropinirole, apomorphine, xylazine, dexmedetomidine, and hydrogen peroxide. These are discussed in the emergency medication lecture notes. Anitemetics Antiemetics are drugs used to control or prevent vomiting. They are typically given parenterally and act either on the chemoreceptor trigger zone (CRTZ), the vomiting center (VC), directly on the gastrointestinal tract (GI), or more than one location. Oral antiemetics are used for long term management of gastrointestinal conditions. They come in five main classes: phenothiazine derivatives, dopamine blockers, antihistamines, serotonin receptor antagonists, and NK-1 receptor antagonists. Metoclopramide (Reglan) A procainamide derivative, it blocks dopamine receptors in the CRTZ and stimulates peristaltic contractions in the gastrointestinal tract, primarily the upper portion. It comes in injectable and tablet form. It is used as a constant rate infusion (CRI) to control vomiting in gastrointestinal diseases such as parvovirus, and orally to treat bilious vomiting syndrome and gastric motility disorders. The adverse effects included behavioral changes such as hyperactivity, constipation, and restlessness. Dimenhydrinate, Diphenhydramine, and Meclizine These drugs are called antihistamines because they block H1 receptors. They act in CRTZ and are used to treat nausea and vomiting from motion sickness and vestibular diseases. Meclizine is particularly good for old dog vestibular syndrome. They come as injectable and tablet form. The most common adverse effect is sedation, although some animals experience excitation instead. Maropitant Citrate (Cerenia) A neurokinin-1 receptor (NK-1) antagonist, maropitant blocks binding of substance P to NK-1 receptors in the CRTZ as well as peripheral receptors in the gastrointestinal tract. It effectively treats more causes of vomiting than other antiemetics. It is often used to stop apomorphine induced vomiting, treat  acute gastroenteritis, pancreatitis, and to treat or prevent vomiting from other causes. Available as an injectable or tablet form, it has a wide margin of safety. Common adverse effects are diarrhea, bloody stool, and anorexia. Ondansetron (Zofran) A serotonin receptor (5-HT3) antagonist, ondansetron binds to 5-HT3 receptors in the CRTZ and peripherally on the vagal nerve, blocking serotonin binding. Its primary effect is from its action on vagal nerve. Zofran is used to treat nausea, particularly if it was caused by chemotherapy. It comes in injectable and tablet form. Reported adverse effects include constipation, diarrhea, and headache. Chlorpromazine A phenothiazine, chlorpromazine blocks dopamine (D2) receptors in the CRTZ. There is some indication it might directly inhibit vomiting center neurons as well. It is used to treat severe vomiting. It is less commonly used than other antiemetics due to the risk of adverse events. It comes in injectable, tablet, and oral solution forms. Reported adverse effects include hypotension, sedation, and ataxia. Butorphanol (as a CRI) A k-agonist--antagonist opioid, its antiemetic action comes from antagonism of the -opioid receptors in the chemoreceptor trigger zone. It is excellent as an antiemetic in parvoviral puppies when the injectable form is used as a constant rate infusion. Adverse effects include sedation, anorexia, diarrhea, and decreased intestinal motility. Antiulcer Medications Ulcerations in the gastric mucosa occur for many reasons- trauma, decreased blood flow, stress, metabolic disease, toxins, and ingestion of sharp or caustic materials, to name a few. Once the mucus is compromised and the mucosa damaged, gastric hydrochloric acid continues to damage the submucosa and retards healing. This causes pain, hematemesis, melena, and anorexia. If severe, ulcers can cause gastric perforation and death. There are five classes of antiulcer medications. They are the H2 receptor antagonists, proton pump inhibitors, antacids, gastromucosal protectants, and prostaglandin analogs. The ACVIM consensus statement: Support for rational administration of gastrointestinal protectants to dogs and cats is found here: https://onlinelibrary.wiley.com/doi/10.1111/jvim.15337. Cimetidine, Ranitidine, and Famotidine These medications are all H2 receptor antagonists. They block H2 receptors on the serosal side of parietal cells, which decreases production of hydrochloric acid. They are used to reduce acid content (increase pH) in the stomach, which allows the mucosa to heal. They also help prevent esophagitis caused by acid reflux. These medications come in injectable and tablet forms. They take a few days to reach full effect and can cause rebound hyperacidity when discontinued. Adverse effects are rare, although they alter metabolism of other medications that require more acidity for absorption. Injectable famotidine given either intravenously or subcutaneously causes a decreased packed cell  volume in cats, so ranitidine is preferred. Give intravenous infusions over at least five minutes to prevent adverse effects. Omeprazole and Pantoprazole As proton pump inhibitors, omeprazole and pantoprazole selectively and irreversibly inhibit the Na+/K+-ATPase pump on the luminal secretory surface of gastric parietal cells, preventing them from pumping hydrochloric acid into the stomach. They are good for long term gastric acid suppression long term. Pantoprazole is available as an injection, while both have oral preparations. Adverse effects include constipation, sedation, ileus, pancreatitis, and central nervous system effects. They are better absorbed in an acidic environment, so should be taken on an empty stomach. They can decrease vitamin B12 absorption, so supplementation might be required with long term use. Aluminum or Magnesium Hydroxide From a group termed antacids, these medications are alkaline preparations that reduce stomach acid by actively binding free hydrogen ions. They are used to decrease acidity (increase pH) of stomach contents without altering parietal cell function. As they are locally acting, they only come as oral preparations. Adverse effects are rare and include constipation or diarrhea. Sucralfate (Carafate) The only direct gastromucosal protectant, sucralfate is a disaccharide sulfate- aluminum complex that reacts with hydrochloric acid to form a paste that buffers the hydrogen ions in the stomach. This paste binds to the exposed proteins on the surface of ulcers to protect the underlying tissues, acting as a band-aid to allow healing. It must be given on an empty stomach, meaning one hour before or two hours after any food and other medications. It is used to coat ulcerated areas to protect them from additional damage and allow healing of gastric and esophageal ulcers. The liquid can be used for both the esophagus and stomach. Tablets can be given whole for gastric ulcers, but must be dissolved in water and given as a slurry when used for the esophagus. The primary adverse effect is constipation. Misoprostol (Cytotec) A prostaglandin E1 analog, misoprostol acts directly on parietal cells to inhibit gastric acid secretion. It also has cytoprotective effect on gastric mucosa by improving blood flow and increasing mucous production by goblet cells. It is used to treat gastric ulceration, particularly that associated with NSAID administration. Misoprostol is given in tablet form. Adverse effects include painful uterine contractions, possible abortion, diarrhea, vomiting, flatulence, and abdominal pain. Antidiarrheal Medications Diarrhea is caused by increased fluid content of the stool. It can be caused by poor water resorption, increased water secretion, parasitism, bacterial infections, and maldigestion, among other causes. If prolonged or severe, it often leads to electrolyte imbalances and dehydration. There are three basic types of antidiarrheals: narcotics, anticholinergics/antispasmodics, and protectants/absorbents. Many veterinarians try to avoid antidiarrheal medications in favor or treating the underlying cause of the diarrhea to achieve resolution. Bismuth Subsalicylate (Pepto-Bismol) A protectant/absorbent medication, it coats and protects inflamed mucosa, as well as binding bacteria and toxins. It is an oral tablet or liquid used to control diarrhea. Adverse effects include constipation. Be aware it shows up white on radiographs! If you see a round, white object on abdominal radiographs, ask the owner if they gave Pepto to the dog. Never use in cats as it causes liver failure, anemia, and gastric ulceration. Kaopectolin (Kao-Pec) Kao-Pec has two active ingredients: kaolinite, which is a clay, and pectin, which is a plant polysaccharide. These ingredients works as a protectant/absorbent. They coat and protect inflamed mucosa and bind bacteria and toxins. It is used to control diarrhea and comes as a liquid or tablet. Adverse effects are minimal and include constipation. Never recommend in cats as some formulations include bismuth subsalicylate. Metamucil, Psyllium, and Bran These drugs are all indigestible plant materials used as bulk-producing agents. The fiber absorbs water and swells, causing stretch of the intestine and stimulating peristalsis. They are used to treat diarrhea caused by a lack of insoluble fiber in the diet, a condition called “fiber responsive diarrhea.” They come in tablet and powder form for addition to food. Adverse effects are rare. Diphenoxylate and Loperamide Pure -agonist opioids, they activate -opioid receptors in the gastrointestinal tract. This increases segmental contractions, decreases intestinal secretions, and enhances intestinal water absorption. They are sometimes used to control acute diarrhea. They come in tablet and oral solution forms. Adverse effects include constipation, ileus, sedation, and centra lnervous system excitement (particularly cats). Aminopentamide An anticholinergic/antispasmodic agent, it inhibits cholinergic receptors, decreasing gastrointestinal secretions and reducing colonic contractions. It is used to treat diarrhea and comes in injectable and tablet form. Adverse effects include sedation, ataxia, hypotension, dry mucous membranes, urinary retention, and dilated pupils. Laxatives and Cathartics Laxatives are substances that increase the liquid content of feces and encourage defecation. Cathartics have irritant effects on intestinal mucosa to promote defecation. They are classified into five categories: saline/hyperosmotic agents, bulk producing agents, lubricants, stool softeners/surfactants, and irritants. Lactulose Lactulose is a naturally occurring sugar molecule that is not absorbed in the small intestines. It is a hyperosmotic agent that causes osmotic pull from the interstitium into bowel, increasing fecal water content and stimulating stretch receptors, leading to increased peristalsis. The feces becomes softer, making it easier to move it past partial obstructions such as a mass compressing the colon. It is used to draw water into the intestinal tract, and helps to control ammonia production in portosystemic shunt and liver failure patients. It comes as a syrup that is very sweet and sticky. Adverse effects include diarrhea, abdominal pain, and nausea. Metamucil, Psyllium, and Bran These drugs are all indigestible plant materials used as bulk-producing agents. The fiber absorbs water and swells, causing stretch of the intestine and stimulating peristalsis. They are used to treat constipation in animals and address sand colic in horses. They come in tablet and powder form for addition to food. Adverse effects are rare. Polyethylene Glycol (PEG) (GoLytely or MiraLax) Polyethylene glycol is an osmotic agent that draws water into the lumen of the intestines, softening the stool. Oral formulations of the medication are used for this purpose. On a side note, PEG is used as a carrier for a few injectable drugs (diazepam is most common) and precipitates when mixed with other solutions. Adverse effects include diarrhea, abdominal pain, bloating, and toxicity. Magnesium Hydroxide (Carmilax) A naturally occurring electrolyte, magnesium acts as a hyperosmotic agent. It draws fluid into the gastrointestinal tract, and serves as cofactor for many enzyme systems in the body. It is used to treat hyperacidity and constipation in cattle. It is available in boluses or a powder for suspension. Adverse effects include diarrhea, abdominal pain, nausea, and electrolyte imbalances. Magnesium Sulfate (Epsom Salts) A naturally occurring electrolyte, magnesium acts as a hyperosmotic agent. It draws fluid into the gastrointestinal tract, and serves as cofactor for many enzyme systems in the body. It is used to treat hyperacidity and constipation in horses and is rarely used in dogs and cats. It comes as a salt powder for suspension. Adverse effects include diarrhea, abdominal pain, nausea, and electrolyte imbalances. Mineral Oil and Petrolatum These products are lubricants that coat and soften fecal material to help it pass through GI tract more easily. They are used to prevent hairballs, treat constipation, and address colic in horses. They are available in liquid or gel/ointment forms. Adverse effects are minimal when used properly.  Docusate Sodium (Ducolax) A stool softener/surfactant, it reduces surface tension and allows water to penetrate dehydrated ingesta. It is absorbed, metabolized, and excreted in bile, then it inhibits fluid absorption in the jejunum. It is used to treat hard, dry feces in small animals, impactions in horses, and is sometimes used in cattle. It comes in tablet form, and there are commercially available enema preparations. Adverse effects are rare. Prokinetics Prokinetics are medications that increase the motility of intestinal tract. This enhances transit of material through GI tract. Prokinetics include several classes of drugs: dopaminergic antagonists, serotonergic medications, motilin-like drugs, cholinergics, acetylcholinesterase inhibitors, and some H2 blockers. Metoclopramide A dopaminergic antagonist and procainamide derivative, it blocks dopamine receptors in the CRTZ and stimulates peristaltic contractions in the gastrointestinal tract, primarily the upper portion. It comes in injectable and tablet form. It is used as a constant rate infusion (CRI) to control vomiting in gastrointestinal diseases such as parvovirus, and orally to treat bilious vomiting syndrome and gastric motility disorders. The adverse effects included behavioral changes such as hyperactivity, constipation, and restlessness. Cisapride A serotonergic prokinetic, it selectively agonizes 5-HT4 receptor in the gastrointestinal tract. It is used to treat constipation (particularly in megacolon cats), as well as gastrointestinal reflux and stasis in cats and dogs. Because it is no longer used in human medicine, it must be obtained through compounding pharmacies. Adverse effects include diarrhea and abdominal pain. Digestive Enzymes Pancrelipase Naturally occurring pancreatic enzymes obtained from freeze dried pork pancreas. The enzymes digest carbohydrates and fats. They are used to treat patients with exocrine pancreatic insufficiency (EPI). They come as a powder that is mixed with food. This mixture is allowed to sit overnight prior to feeding, breaking down the nutrients prior to ingestion. Adverse effects are hypersensitivity reactions, nausea, and diarrhea. Hepatic Support Hepatic support medications are used to treat patients with liver disease, as well as those exposed to known hepatotoxins. Most of these medications act to reduce free radical damage to the liver, support the glucuronidation pathway, or to support bile production and movement. Denamarin Denamarin is a nutritional supplement containing s-adenosylmethionine (SAMe) and silybin (milk thistle) in chewable tablet form. SAMe is methionine and an  ATP molecule. It is used in transmethalation, transsulfuration, and aminopropylation pathways. It increases glutathione levels, protects hepatic cells from death, and is an antioxidant that reduces cellular injury. Silybin improves liver function, is an antioxidant, and directly increases glutathione levels, particularly in cats. It also supports increased protein production and is protective in cases of Amanita mushroom toxicity. It is used to treat hepatotoxicity, chronic liver disease, and support liver function after injury. Adverse effects have not been reported in dogs and cats. n-Acetylcysteine A derivative of the amino acid cysteine, in the body, it is metabolized into L- cysteine then glutathione, providing additional support to the hepatic metabolic pathway. n-acetylcysteine is given orally or parenterally to treat acetaminophen toxicity. It comes in sterile injectable form, as well as a liquid for nebulization and oral preparations. Giving the injectable medicaiton orally achieves appropriate serum levels. Sometimes the nebulization preparation is administered subcutaneously in veterinary patients. When used in this manner, the injections should be in the cranial pectoral area to allow for easier drainage if an abscess forms. Adverse effects include vomiting and nausea when given orally, and abscesses if inhalant preparation given subcutaneously. Ursodeoxycholic Acid (Ursodiol) A secondary bile acid produced by intestinal bacteria, ursodiol is used to treat patients with cholangitis and cholestasis. It is highly hydrophilic and increases the water content in the bile, decreasing viscosity. This improves bile flow and reduces the risk of gall bladder mucocele formation in susceptible patients. It also exerts anti-inflammatory effects to reduce cholangitis. Administered in tablet form, the main adverse effect is diarrhea. Miscellaneous Many other medications are used in gastrointestinal disease. These include antibiotics, antiinflammatory agents, weight loss products, and appetite stimulants. Metronidazole A nitroimidazole antibiotic, metronidazole inhibits nucleic acid synthesis by disrupting DNA integrity. It also mitigates cell mediated immunity at the mucosal surface, reducing inflammation. It is used to treat specific gastrointestinal infections such as Giardia, Salmonella, Clostridium, Helicobacter, and some amoebas, and in some types of gastroenteritis. It comes in injectable and oral forms. The injectable preparation is degraded by light, so the bag and administration set should be covered while the infusion is administered. Adverse effects include anorexia, hepatotoxicity, neutropenia, vomiting, and diarrhea. Sulfasalazine A sulfonamide antibiotic, it is used as an immunosuppressive and anti- inflammatory agent. The exact mechanism of action in treating colitis is unknown, however it is converted into a sulfa compound and aspirin in the  liver. It is used to treat inflammatory bowel disease in dogs. When no other treatments are working, it is sometimes used cautiously in cats. It comes in tablet form. Adverse effects are keratoconjunctivitis sicca (KCS), anorexia, vomiting, and hepatopathy. Any patient on sulfasalazine who develops conjunctivitis or other ocular signs should have a Schirmer tear test performed. Azathioprine An immunosuppressive and antiinflammatory agent, azathioprine inhibits purine synthesis, limiting the cell’s ability to produce DNA and RNA. It is used to treat inflammatory bowel disease. It comes in injectable and tablet forms. Adverse effects include bone marrow suppression, gastrointestinal upset, pancreatitis, and hepatopathy. Probiotics (FortiFlora, Proviable) Probiotics consist of naturally occurring bacteria and is classified as a nutritional supplement. They provide large amounts of healthy intestinal bacteria, improving immune function and restoring intestinal flora balance. They are used to treat stress related gastrointestinal upset, small intestinal bacterial overgrowth (SIBO), diarrhea from diet changes, and antibiotic associated diarrhea. There are different varities that comes as powders for oral use, tablets, pastes, and capsules. Adverse effects are rare. Bloat Guard Bloat guard is an antifoaming agent and surfactant. It changes surface tension and decreases bubble formation in the top layers of the rumen. It is used to treat frothy bloat in ruminants and comes as an oral liquid. Adverse effects are rare if used properly. Mirtazapine Mirtazapine is an atypical antidepressant and acts as an appetite stimulant. It antagonizes alpha-2 adrenergic and serotonin receptors, acts as an antihistamine. These actions directly increase appetite. It is used to improve appetite in anorectic cats and dogs. It comes in tablet form. Adverse effects are sedation, vocalization, and hypotension. Benzodiazepines Benzodiazepines enhance the effect of GABA, causing hypothalamic depression. They also act directly on the brain in manner that mimics hunger. They are used to stimulate appetite. Benzodiazepines come in injectable, tablet, oral solution, and rectal gel formulations. Adverse effects include lethargy, hypoventilation, and incoordination. Oral diazepam should never be used in a cat because it can cause fatal hepatic necrosis. Dental Care Products Dental care products are used to promote and maintain oral health. There are many, many products available in the stores. They come as solutions, gels, toothpastes, and premoistened sponges. When selecting chewable dental treats, it is important to select only those that are Veterinary Oral Health Council (VOHC) certified. The VOHC has researched the treats extensively and only award their seal to treats that will not damage the pet’s enamel. It is important to educate owners that human dental health products can be fatal for animals due to levels of toxic substances such as xylitol and fluoride. Brushing teeth should be performed daily and is most effective if started prior to development of tartar or after an anesthetized dental prophylactic cleaning. Food as Medicine Many diseases benefit from adding or limiting specific nutrients to their food. Some specialty foods are available without prescription, such as novel protein diets. Other diets require a prescription because they have the potential to cause harm if not used properly. These are typically calorie limited, the minerals not balanced for growing bones, or other nutrients are restricted. Homemade, boutique, raw, and exotic ingredient diets are not recommended because they do not meet the nutritional needs of pets. They are often associated with preventable diseases, and some may cause a health risk to the owners. Read this article about therapeutic diets: https://vetnutrition.tufts.edu/2017/01/therapeutic_diets/. Therapeutic Diets Multiple companies produce therapeutic diets that require a prescription. Hill’s Science Diet trademarked the term “Prescription Diet,” so technically all other diets are called therapeutic. Purina and Royal Canin also have therapeutic lines. Each diet is formulated to meet the unique nutritional needs of animals suffering from a specific disease process. They may not be nutritionally complete for puppies or animals who don’t have the particular disease, which is why they are restricted to use only with a veterinarian’s prescription. This list gives examples of common therapeutic diets: Aging care diets (Hill’s g/d, RC Maturity) Brain care diets (Hill’s b/d, Purina NC) Cardiac (Hill’s h/d, RC Early Cardiac) Dental care diets (Hill’s t/d, RC Dental, Purina DH) Dermatologic problems (Hill’s Derm Complete, RC Skin Support, Purina DRM) Diabetes mellitus (Hill’s w/d, RC Glycobalance) Gastrointestinal (Hill’s i/d, RC GI low fat, Purina EN) Hepatic (Hill’s l/d, RC Hepatic) Hyperthyroidism (Hill’s y/d) Hypoallergenic (Hill’s z/d, RC Hydrolyzed or Selected Protein, Purina HA) Joint support diets (Hill’s j/d, RC Mobility Support JS, Purina JM) Recovery (calorie dense) diets (Hill’s a/d, RC Recovery, Purina CN) Renal (Hill’s r/d, RC Renal Support, Purina NF Kidney Function) Urinary health (Hill’s s/d, RC Urinary SO, Purina UR Ox/St) Weight loss (Hill’s Metabolic/r/d, RC Weight Control/Satiety, Purina OM) Here are some additional veterinary nutrition resources for review: http://vetnutrition.tufts.edu/ https://vet.osu.edu/vmc/companion/our-services/nutrition-support-service http://veterinarycalendar.dvm360.com/therapeutic-diets-food-you-can-use- proceedings Websites for home made diet recipes: https://secure.balanceit.com/index.php - Requires vet approval to see recipes https://vetgirlontherun.com/veterinary-continuing-education-homemade- veterinary-diets-catherine-lenox-vetgirl-blog/ http://vetnutrition.tufts.edu/2016/07/should-you-make-your-own-pet-food-at- home/ https://vcahospitals.com/know-your-pet/nutrition-home-made-diets