2- GI Drugs Flashcards
What antacids are fast acting, not useful for ulcers, and should be used with caution in pts with CHF?
Sodium bicarbonate
Pt taking a calcium carbonate antacid should be cautioned on what 2 side effects?
“Milk alkali” syndrome- high blood calcium + metabolic alkalosis
Acid rebound
What are the SEs of magnesium hydroxide and aluminum hydroxide? (antacids)
Magnesium hydroxide- diarrhea (also used at laxative)
Aluminum hydroxide- constipation
Combined to decrease SEs
Magnesium hydroxide and aluminum hydroxide (antacids) should be used with caution in patients with what?
Renal function (accumulation)
What drug interaction between magnesium hydroxide and aluminum hydroxide is of importance when they are combined?
Decreased absorption
What is the use of antacids?
Temporary relief of heartburn, gastritis
Drug interactions
Theophylline, ketoconazole, quinolone abx, and tetracycline form complexes with what meds?
Antacids
Drug interactions
What meds will decrease the absorption of digoxin, phenytoin, and propranolol?
Antacids
Drug interactions
What meds will increase the elimination of phenobarbital and salicylates leading to alkalinization of urine?
Antacids
What drugs are H2 antagonists?
(decrease GI acid formation through H2 receptor blockade, all OTC)
Cimetidine (Tagamet)
Ranitidine (Zantac)
Famotidine (Pepcid)
Nizatidine (Axid)
What is the use of H2 blockers?
Ulcers (used at night)
GERD (adjunct)
Pre-anesthesia
How are H2 blockers given for severe allergic reaction?
In combo with H1 antagonists
How are H2 blockers metabolized and excreted?
Metabolized by liver
Excreted by kidney
What are the SEs of H2 blockers?
HA, dizziness, nausea, rash/ itch
(worse in elderly)
What drug has an anti-testosterone effect and can therefore be beneficial in women, but cause gynecomastia/ loss of libido/ impotence in men?
Cimetidine
(H2 blocker)
Drug interactions
What drug inhibits metabolism of warfarin, phenytoin, theophylline, and digoxin?
Cimetidine
(H2 blocker)
What drugs end in “prazole”?
PPIs
(Omeprazole, Esomeprazole, Lansoprazole, Rabeprazole, Pantoprazole)
What is the DOC for GERD?
PPIs (“prazoles”)
What drugs irreversibly block acid formation and have a duration of action of 2-3 days as new pumps are formed?
PPIs (take on empty stomach, in a.m.)
What are the SEs of PPIs?
Nausea, diarrhea, colic, osteoporosis, decrease Mg++ absorption
What are the uses for PPIs (aside from GERD = DOC)? (3)
Ulcers refractory to tx w/ H2 antagonists
Pts on NSAIDS
Zollinger-Ellison syndrome
What is the MOA of Misoprostol (Cytotec)?
PGE1 analogue
What drug is used to prevent or reduce NSAID-induced damage?
Misoprostol (Cytotec)
What are the SEs and contraindication of Misoprostol (Cytotec)?
SEs: diarrhea, nausea, HA, dizziness
C/i: pregnancy (can induce abortion)
What drugs are prokinetic agents? (3)
Metoclopramide
Bethanechol
Erythromycin
What is the use of Metoclopramide?
Antiemetic
What are the SEs of Metoclopramide?
Parkinson’s-like sxs, antiemetic, GI cramping, diarrhea
Contraindication to use of Metoclopramide?
Pregnancy (methemoglobinemia in infants)
What prokinetic agent is used to tx diabetic gastroparesis?
Erythromycin
MOA/ SEs for Bethanechol? (prokinetic agent)
MOA: muscarinic agonist
SEs: diarrhea, abd cramps
What are the most commonly used muscarinic antagonists, used to decrease GI spasms?
Glycopyrrolate and dicyclomine
What are the SEs of Glycopyrrolate and Dicyclomine? (antispasmodics- muscarinic antagonists)
Dry mouth, sedation, constipation
Pt presents with IBS. What GI drug should you prescribe to decrease GI effects and decrease pain transmission?
Amitriptyline
Pt presents with IBS WITH diarrhea. What antispasmodic agent should be prescribed and what is its SE?
Eluxadoline (opioid agonist)
SE: severe constipation
What drugs are very effective for N/V induced chemotherapy, radiation, and gastric diseases, but NOT used for motion sickness?
5HT3 antagonists; “setrons”
Ondansetron (Zofran)
Granisetron (Kytril)
Dolasetron (Anzemet)
Palonosetron (Aloxi)
What are the SEs for the 5HT3 antagonists? (“setron”)
HA, constipation, dizziness
What antiemetic drugs can be used post-op, for gastroenteritis, or chemo SEs, AS WELL AS motion sickness (but not DOC)?
Prochlorperazine, Promethazine
(block DA, muscarinic, histamine receptors)
What are the SEs of Prochlorperazine and Promethazine?
Highly sedating
You are treating a pt with chemo-induced N/V with Dronabinol/ medical marijuana (THC). What SE should they be aware of?
Stimulates appetite
What drug might you combine a 5HT3 antagonist for increased antiemetic effects?
Aprepitant- NK1 antagonist
What is the best bulk-forming laxative and what are common SEs?
High-fiber diet (+ water)
SEs: bloating, flatulence
(other fiber sources: Methylcellulose, Psyllium, Polycarbophil)
What are the types of osmotic laxatives (NOT absorbed, pulls water w/ them)?
Magnesium hydroxide- stimulates GI tract, increases peristalsis
Sodium salts- oral/ enema, caution w/ overuse
Artificial sweeteners (Sorbitol, Mannitol, Sucralose)
Pt undergoing prep for colonoscopy will likely be taking what laxative?
(large volume consumed + electrolytes)
Polyethylene glycol
What OTC laxative may be used for occasional constipation (up to 7 days) and what pt edu should be provided?
Miralax (polyethylene glycol)
LOTS OF WATER
What laxative is used to decrease blood ammonia levels in pts with cirrhosis or liver disease and what are its SEs?
Lactulose
SEs: flatulence and diarrhea
Female pt who is pregnant presents to your office with GI complaints. What laxative can be prescribed in order to stimulate peristalsis and enhance secretion/ inhibit absorption of H2O?
Bisacodyl, Senna
(mucosal agents)
What mucosal agent is used for diagnostic surgery procedures (colonoscopy) and what is its c/i?
Castor oil
C/i: pregnancy (stimulates uterus)
Although generally not very effective and not recommended, what laxatives are used as lubricants/ stool softeners?
Mineral oil
Docusate
Glycerin
What are the cautions with mineral oil use? (lubricant/ softener)
Inhibits absorption of fat soluble vitamins, oral inhalation (pneumonia), leaking (need diaper)
What stool softeners are safe to be used long-term/ chronically?
Lubiprostone, Linaclotide
What is the use of Lubiprostone?
Increase fluid secretion, softer stool
(PGE1 analogue, activations Cl channels)
Pt presents with IBS WITH constipation. What laxative can be used and what is a SE?
Linaclotide
SE: diarrhea
Contraindication to Linaclotide?
Children and teens < 18 yo (risk of dehydration)
What is considered first line for tx of constipation?
Diet, water, exercise
(THEN drugs)
What are the contraindications to laxative use?
- N/V/ abd cramps
- Undiagnosed abd pain
- Appendicitis
- Intestinal obstruction
What are the concerns with overuse of laxatives?
Fluid/ electrolyte imbalance
Spastic colitis
UC
(can only use Lubiprostone and Linaclotide chronically)
What anti-diarrheal agents may benefit watery diarrhea by increasing bulk?
Adsorbents
(absorb water, form gel-like mass)
(dietary approach = bananas, applesauce, rice)
What opioid may be used in the tx of diarrhea, has low abuse potential because it does not enter the CNS and has SEs of abd pain and constipation?
Loperamide (Imodium)
Pt presents with sxs of atropine poisoning. What anti-diarrheal have they likely overdosed on?
Diphenoxylate/ atropine (Lomotil)
What opioid may be used in the tx of diarrhea, is combined w/ atropine to reduce abuse potential and increase effectiveness?
Diphenoxylate/ atropine (Lomotil)
What anti-diarrheal is most commonly used in the tx of “traveller’s diarrhea” to absorb water and pathogens?
Bismuth subsalicylate
(salicylate = anti-inflammatory)
SE of bismuth subsalicylate? (Pepto-Bismol)
Black tongue, mouth, stool
Contraindications to bismuth subsalicylate (Pepto-Bismol)?
Pts allergic to aspirin
Children (risk of Reyes)
Asthmatics (caution)
What GI drug should be considered for tx of IBD (best for UC) and what is its c/i?
Sulfasalazine (5-ASA + sulfapyridine)
C/i: children (Reyes)
Pt presents with severe UC or Crohn’s that is refractory to other drug treatments. What drugs can be used?
Infliximab, Adalimumab
(TNF alpha blocking agents, anti-inflammatory effects)
What is the major adverse effect of Infliximab and Adalimumab?
(TNF alpha blocking agents used for refractory IBD)
Immunosuppression (TB test required)
What drug coats and dissipates gas to decrease bloating and flatulence and can be used in combo with antacids?
Simethicone
