SV_Anti-Ulcer Drugs, Laxatives, and Anti-Emetics.pptx

ANTI-ULCER DRUGS, LAXATIVES, AND ANTIEMETICS ULCER FORMATION GI protective Mucus Bicarbonate Prostaglandins Ulcer causing HCl Pepsin Helicobacter Pylori NSAID’s ANTACIDS Use - Little use in gastric and duodenal ulcer and gastric reflux. Common use in heartburn and indigestion. Rapid action, relieves...

ANTI-ULCER DRUGS, LAXATIVES, AND ANTIEMETICS ULCER FORMATION GI protective Mucus Bicarbonate Prostaglandins Ulcer causing HCl Pepsin Helicobacter Pylori NSAID’s ANTACIDS Use - Little use in gastric and duodenal ulcer and gastric reflux. Common use in heartburn and indigestion. Rapid action, relieves gastric discomfort. Limited healing of ulcer. Take after meals and at bedtime. Liquids more effective. Combinations of Al+++ and Mg++ most used. Frequent dosing, chalky taste, liquid is inconvenient, alters absorption of some drugs. All are weak bases. Calcium - constipation and “acid rebound”. Magnesium – diarrhea. Aluminum - constipation. NaHCO3 - Makes CO2 gas, belching and gas, alkalosis. ANTI-SECRETORY DRUGS: HISTAMINE 2 (H2) RECEPTOR ANTAGONISTS Drugs - Cimetidine (Tagamet ), famotidine (Pepcid ). Use - Moderate effectiveness. Gastric ulcer, duodenal ulcer, gastric reflux, heartburn and indigestion. Relieve pain in days, heal ulcers in weeks-months. More effective at bedtime. Adverse effects are uncommon Rare = confusion, dizziness, restlessness, agitation, bradycardia, nephritis, hepatitis, B12 deficiency More adverse effects with cimetidine - impotence, gynecomastia, drug interaction Block 40-70% of H+ secretion ANTI-SECRETORY DRUGS: PROTON PUMP INHIBITORS (PPI’S) Drugs - Omeprazole (Prilosec ), esomeprazole (Nexium ) lansoprazole (Prevacid ), pantoprazole (Protonix) Use – Common use. Gastric and duodenal ulcer, gastroesophageal reflux, NSAID ulcers. Relieve pain in days, heal ulcers in weeks-months. High effectiveness and long durations, can be used one time per day. Blocks 70-90% of H+ secretion. Adverse effects: Minor = diarrhea, abdominal pain, nausea, headache Gastric atrophy: ↓ acid Gastrointestinal infections, pneumonia: ↓ acid MUCOSAL PROTECTIVE AGENT Drugs - Bismuth subsalicylate, colloidal bismuth subcitrate Pharmacological effects. Binds to ulcer and protects from acid and pepsin. Inhibits pepsin activity. Has antibacterial activity against the bacterium Helicobacter pylori. Use. Effectiveness limited. Used in combination with other drugs to destroy Helicobacter pylori in gastric and duodenal ulcer. Use in heartburn and indigestion. Adverse effects. Black tongue and stool, tinnitus. HELICOBACTER PYLORI TREATMENT Antibiotics: treatment is a combination of 3-4 meds 1o Clarithromycin (Biaxin ), metronidazole, amoxicillin; 2o tetracycline. Bismuth subsalicylate (Pepto Bismol ). Pharmacological effects: Destroys Helicobacter pylori in the G.I. tract of patients with ulcers. Indication: Gastric and duodenal ulcer. Treatment Regimens Bismuth quadruple therapy: PPI, bismuth, metronidazole, and tetracycline. Recommended Triple therapy: three 1o antibiotics plus PPI. Antibiotic adverse effects: diarrhea, abdominal pain, LAXATIVES Used to treat constipation. The most common cause of constipation is reduced fluid in the stool due to a diet deficient in fiber and fluid. Uses of laxatives: Reducing painful elimination with hemorrhoids Reducing the need to strain to defecate with cardiovascular disease For loss of muscle tone in geriatric patients Emptying the bowel for a procedure LAXATIVES Bulk forming: Psyllium (Metamucil, Benefiber) Polysaccharides and celluloses that swell in water to from a gel to soften the feces and increase its mass. Produces a soft stool in 1-3 days. Adverse effects. Gas, bloating, intestinal obstruction. Stool Softeners: Docusate Increases entry of water into feces. Inhibits fluid reabsorption. Softens/lubricates the feces. Produces a soft stool in 1-3 days. Low effectiveness. Adverse effects. Few – bitter taste, nausea. LAXATIVES Osmotic laxatives: Magnesium hydroxide (Milk of Magnesia) Osmotic effect to retain fluid in the intestine. Softens/expands fecal mass, increases peristalsis. Produces a semifluid stool in 3-12 hours. Low doses for constipation. Higher doses to empty the bowel for surgical or diagnostic procedures. Adverse effects: Cramps, fluid loss, electrolyte imbalances. Use with caution in renal failure. Must increase fluid intake. LAXATIVES Stimulants: Directly increase intestinal motility, increased secretion of fluid and electrolytes. Produce a semi-fluid stool in 3-12 hours. Bisacodyl – enteric coated, should not be chewed or crushed. Senna (Senokot®) – may color the urine yellow or brown. Adverse effects: Cramps, watery stools, nausea, dehydration, electrolyte imbalance, colitis. Can cause dependence on laxatives to maintain normal bowel function. Used occasionally for < 1 week. ANTIEMETICS Pathophysiology of vomiting Direct stimulation of the vomiting center of the brain Indirect stimulation of the vomiting center: stimulation of the Chemoreceptor Trigger Zone (CTZ) which in turn activates the vomiting center Antiemetics Given to suppress nausea and vomiting Chemotherapy Induced Nausea and Vomiting (CINV) Anticipatory, acute, delayed Prevention is best approach ANTIEMETICS SEROTONIN RECEPTOR ANTAGONISTS Ondansetron (Zofran)PO, IM, or IV, granisetron PO, IV, transdermal Uses: N and V caused by chemotherapy (CINV), radiation, viral gastroenteritis, anesthesia, and pregnancy MOA: Blocks type 3 serotonin receptors (5-HT3 receptors) in the CTZ and on afferent vagal neurons in the upper GI tract Effectiveness increased when given with dexamethasone DOPAMINE ANTAGONISTS Prochlorperazine (Compazine); promethazine (Phenergan) Uses: Post op and V, CINV MOA: Block dopamine receptors in the CTZ Adverse Effects: extrapyramidal, anticholinergic, sedation, hypotension Metoclopramide (Reglan) - can also be used as an appetite stimulant Adverse Effects: extrapyramidal OTHER ANTIEMETICS Glucocorticoids: methylprednisolone and dexamethasone Benzodiazepines: Lorazepam (Ativan), Cannabinoids: dronabinol (Marinol) and nabilone (Cesamet) Drugs for motion sickness: Scopolamine Antihistamines NAUSEA AND VOMITING OF PREGNANCY (NVP) Extremely common; Generally controlled with non-drug measures About 10% of women with NVP require drug therapy First line therapy: doxylamine ad vitamin B6. available in a fixed-dose combination (Diclectin, Diclegis) Second line therapy (if first-line therapy not successful): Prochlorperazine Metoclopramide Ondansetron Methylprednisolone - last resort and after 10 weeks gestation).