GI Notes

Monitoring for tumor necrosis factor (TNF) inhibitors: TNF is a protein that is a pro-inflammatory cytoskine. Once treatment has began important to monitor the concentration of Anti- TNF levels, concentration of albumin & CRP (c-reactive protein) since these can alter effectiveness of anti-TNF. (Biologics are second line treatment for Crohn’s disease and ulcerative colitis). IA GERD First line - lifestyle modifications to decrease alcohol intake, lose weight / avoid overeating, do not lie down for 3 hours after eating, decrease spicy, greasy food, quit smoking 1) First line medications – Antacids: Over the counter – Calcium Carbonate (Tums), Magnesium and Aluminum Salts Mechanism of Action: Partially neutralize HCI in gut. By increasing the pH level, the of pepsin is also inhibited. Another antacid product combo with alginic acid forms a viscous solution on surface of gastric contents – as a barrier to GERD Uses: Mild, intermittent symptoms ( 2 times per wk) OR as breakthrough for patients taking other acid suppression therapies. Acid indigestion, heartburn, dyspepsia, GERD Contraindications / precautions: No significant contraindications exist ALL antacids can interfere with absorption of oral drugs if given at same time SEPARATE the admin times with other drugs by 1 to 3 hours (see nursing implications) Side effects / Adverse reactions: Diarrhea, constipation, electrolyte imbalances, aluminum accumulation in serum Nursing implications: - Those taking Digoxin, Phenytoin, Ketoconazole, iron salts, Isoniazid, Quinolones and Tetracycline may be reduced if taken within 2 hours of antacids. BE SURE know all meds, herbals and OTC (over the counter meds) pt is taking - Antacids should not be taken within 1 hr of most other meds - Check electrolytes intermittently for imbalances 2) Second line medication – H2 blockers – “tidine” meds: Famotidine (Pepcid), Cimetadine (Tagamet), Ranitidine (Zantac), Nizatidine (Axid) Mechanism of action: H2 receptor antagonists (H2RA) inhibit histamine action on H2 receptors, which are found on the acid-secreting gastric parietal cells. The action reduces the secretion of basal gastric acid, as well as hydrogen ion concentration contact: Uses: Prevention and treatment of gastric & duodenal ulcers, heartburn, acid indigestion, and GERD. Decrease. H2 blockers also for allergic reactions Contraindications / precautions: Caution with hepatic and renal failure, In older patients can cause confusion (most common) and agitation Side effects / Adverse reactions: Diarrhea (most frequent), constipation - Decrease in stomach acid may increase Candida / bacterial growth in gut = increased risk for pneumonia - Cimetidine: may bind with androgens causing gynecomastia & impotence (effects reverse after stop taking - When given IV may cause hypotension & dysrhythmias Nursing implications: - Antacids can decrease absorption especially with Cimetidine - Cimetidine has many drug interactions so make sure you know all OTC, Herbals, meds patient on - PO meds can be taken with or without food - Avoid alcohol - Smoking may decrease effectiveness - Teach signs of GI bleeding: black, tarry stools, coffee-ground emesis – Call practitioner if occurs - Notify practitioner if respiratory problems - 3 to 5 small meals may be tolerate better than large meals 3)– PPIs – “prazole” drugs Omeprazole (Prilosec), Esomeprazole (Nexium), Lansoprazole (Prevacid), Pantoprazole (Protonix) Mechanism of Action: Suppresses the secretion of gastric acid - blocks the last step common pathway for gastric acid formation by combining with hydrogen, potassium and adenosine triphosphate in the gastric parietal cells: decrease hydrogen ion transport into the gastric lumen Uses: Short-term 4 – 8 wks for duodenal ulcers assoc. with H. Pylori, gastric ulcers, erosive gastritis & GERD. Long term hypersecretory conditions – Zollinger – Ellison syndrome Prevention and treatment gastric & duodenal ulcers, heartburn, acid indigestion, and GERD. Decrease. H2 blockers also for allergic reactions Contraindications / precautions: - Use caution in hepatic impairment - May interfere with the metabolism of: Diazepam, phenytoin and warfarin – may cause HIGHER serum levels of these drugs - May interfere with drugs that depend on gastric pH for absorption such as: Ketoconazole, Digoxin, Ampicillin, Magnesium, Vitamin B12, Calcium and Iron salts Side effects / Adverse reactions: Headache (most frequent), diarrhea, nausea, vomiting, flatulence - Long term use may increase risk of developing C-diff & GI infections (Salmonella), pneumonia, rebound acid hypersecretion, osteoporosis, fractures, hypomagnesemia, & B12 deficiency, (Need monitoring of labs intermittently) Nursing implications - Teach to not open, crush or chew capsules and to take before meals - Teach to follow up if symptoms unresolved after 4 to 8 wks - Encourage to intake adequate calcium and Vit D - Teach symptoms hypomagnesemia: tremor, muscle cramps, seizures, dysrhythmias - If on Warfarin, Phenyotin, Diazepam – use caution - Watch with meds that depend on gastric pH for absorption Antacids Aluminum hydroxide, Mg hydroxide (Maalox, Mylanta) liquid Calcium carbonate, Mg hydroxide (Tums, Rolaids) Sodium bicarbonate (Alka Seltzer, baking soda) MOA Weak bases act to locally neutralize acid, effective for symptom relief Dosage ● Effective (sometimes) in control of episodic GERD, dyspepsia ● Are not for long term therapy in patients with moderate to severe disease ● Rapid onset of action, generally short acting, one to two hours ● Use after meals or at bedtime Adverse Effects ● Diarrhea-unabsorbed Mg ● Constipation-Aluminum ● Metabolic Alkalosis- absorption of unreacted alkali ● Sodium overload- especially in patients with heart/renal failure H2 Receptor Antagonists— take without regards to meals, kidney reduction Cimetidine (Tagamet) Famotidine (Pepcid) Nizatidine (Axid) Ranitidine (Zantac) MOA Reversibly inhibit the H2 receptors on gastric parietal cells which dec acid secretion and pepsin activation ● They are particularly effective in blocking nocturnal acid secretion (which depends largely on histamine) ● Less effective than PPI’s at blocking meal stimulated acid, which is stimulated by gastrin, and Ach as well as histamine Dosage ● Duration of action around 10 hours, hence BID dosing is commonly given to block 24-hour acid secretion ● Take without regard to meals, monitor for drug interactions, may be scheduled or used on an as needed basis Adverse Effects ● Generally, well tolerated, may experience headache, dizziness, confusion ● Crosses the placenta, though no known adverse effects on the fetus ● May decrease absorption of other drugs ● tetracycline, fluoroquinolones Cimetidine (Tagamet) ● Confusion, mental status changes (elderly) ● Anti-adrogenic effects: Gynecomastia and impotence in men Drug Interactions ● Most reports are with Cimetidine ● Cimetidine inhibits cytochrome P-450 enzyme system ● Potential to inc metabolism and inc concentration and possibly toxicity of some drugs (Warfarin, phenytoin, theophylline, Cyclosporine, propranolol) Contraindication ● hypersensitivity to H2RAs ● Consider dose reduction in elderly and renal impairment PPIs Omeprazole: Pantoprazole MOA Inhibit gastric proton pumps located on the parietal cells producing long suppression of acid secretion ● Duration of acid inhibition is up to 24 hours due to the irreversible inactivation of the proton pump ● Unlike H2 blockers, PPI’s block the final common pathway of acid secretion, the proton pump itself GERD: ● Considered the most effective agents for both erosive and nonerosive reflux disease with respect to healing and for management of severe symptoms (i.e.-erosive esophagitis, strictures, Barretts PUD: ● H pylori associated ulcers: Healing, and eradication of organism ● Gastric prophylaxis in patients who continue to take NSAIDs and are high risk (elderly, prior PUD, etc.) Dosage ● Should be taken 30-60 minutes before meals, because they only bind to active proton pumps, and serum half life is short ● Do not crush, chew or split delayed release tabs Once daily ● PUD / GERD healing ● Initial symptom control ● Maintenance ● NSAID prophylaxis/gastroprotection Twice daily ● H pylori eradication regimens ● severe / complicated GERD (med to long term) ● severe / complicated PUD (short term) Adverse Effects Generally, well tolerated and safe as a class of drugs ● Headache, diarrhea, abdominal pain, and nausea and constipation and bloating ● May inhibit cytochrome P-450 to various degrees ● May affect the absorption of drugs which are dependent upon low gastric pH (iron, digoxin, and ketoconazole) ● May inhibit clopidogrel ● Omeprazole pregnancy C all others B Long term effects ● Malabsorption of Ca+ and Mg ● Risk for infection (C diff & pneumonia) Mucosal Protectants Sucralfate (Carafate) ● Approved for duodenal ulcers ● Stress ulcer prophylaxis ● Not effective for H pylori MOA Forms viscous adhesive substance that attaches and protects ulcer from noxious gastric content ● Takes 1-2 hrs to work ● take on empty stomach; Adverse event: constipation contraindication: hypersensitivity to sucralfate; monitor for drug interactions Bismuth subsalicylate (peptol bismol) MOA Acid secretion suppressing effects. It inhibits the antimicrobial effects preventing h pylori adhesion to epithelial cells. Takes 10-14 days (H pylori tx) Adverse events: ● black stools, darkened tongue, constipation, tinnitus ● Contraindication: ● hypersensitivity to salicylates ● Avoid in pregnancy and lactation