Meds Affecting Digestion and
Nutrition
(General Key Points)
N203
ATI (Unit 10)
Digestion and Nutrition -
GI tract is the route of administration and the target of action
GI effects are common (abdominal pain, constipation, nausea)
When peptic ulcers are caused by H. pylori, non-antibiotics promote healing but
only antibiotics will cure the disease.
Drug therapy for peptic ulcers is directed at controlling symptoms, facilitating
healing, lowering risk for complications, and preventing relapse
Prevention of emesis is more effective than treating it.
Histamine2 (H2) Receptor
Agonists
N203
ATI (Unit 10)
Digestion and Nutrition -
Proto: ranitidine (Zantec) — Others: cimetidine (Tagamet),
Expected Action: nizatidine (Axid), famotidine (Pepcid)
Selectively block H2 receptors in parietal cells to suppress gastric acid secretion
Therapeutic Uses: OTC for heartburn, sour stomach, and indigestion
Gastric/peptic ulcers / GERD / hypersecretory conditions (Zollinger syndrome)
In conjunction with antibiotics to treat ulcers caused by H. pylori.
Adverse Effects: libido / impotence
CNS effects (lethargy, depression, confusion) - frequent in elderly ĉ renal or
liver dysfunction.
Contraindications/Precautions: ♀ (B)
risk of bacterial colonization of stomach and respiratory tract
Interactions:
Warfarin, phenytoin – metabolizing enzymes inhibited by cimetidine levels
Concurrent use of antacids absorption H2-receptor antagonists
Education: Stop drinking, stop smoking, eat smaller, more frequent meals
Ranitidine can be taken without regard to food
Proton Pump Inhibitor
N203
ATI (Unit 10)
Digestion and Nutrition -
Proto: omeprazole (Prilosec) — Others: pantoprazole (Protonix),
Expected Action: lansoprazole (Prevacid), esomeprazole (Nexium)
gastric acid secretion by irreversible inhibition of enzyme that produces it.
Reduce basal and stimulated acid production
Therapeutic Uses:
Gastric/peptic ulcers / GERD / hypersecretory conditions (Zollinger syndrome)
Adverse Effects: Insignificant ĉ short-term treatment
Contraindications/Precautions:♀ (C)
risk pneumonia d/t pH promoting bacterial colonization
Interactions:
Delayed absorption of Ampicillin, digoxin, iron, ketoconazole if concurrent
Education:
IV pantoprazole may cause thrombophlebitis, headache, or diarrhea.
Sucralfate
N203
ATI (Unit 10)
Digestion and Nutrition -
Expected Action: Proto: Sucralfate (Carafate)
Acidic conditions Δ sucralfate to viscous gel that adheres to and protects ulcers.
Therapeutic Uses: Acute duodenal ulcers
Investigational use for gastric ulcers and GERD
Adverse Effects: No systemic effects
Avoid constipation by > 1500 cc and fiber
Contraindications/Precautions: ♀ (B)
Interactions: Antacids interfere with absorption of sucralfate.
absorption of phenytoin, digoxin, warfarin, ciprofloxacin
Education: Take on empty stomach, 4x per day
Antacids
N203
ATI (Unit 10)
Digestion and Nutrition -
Proto: Al(OH)3 gel (Amphojel), Others: AlCO3,
Expected Action: Mg(OH)2 (Milk of Magnesia), NaHCO3
Neutralize gastric acid and inactivate pepsin
Mucosal protection through stimulation of prostaglandin production
Therapeutic Uses: Peptic ulcer disease and GERD
Adverse Effects: Al/Ca compounds constipation, Mg compounds diarrhea
Na+-containing fluid retention Al(OH)3hypophosphatemia
Mg2+ compounds toxicity with renal impairment.
Contraindications/Precautions: ♀ (C) GI perforation or obstruction
Interactions:
Aluminum-compounds bind to warfarin, tetracycline and their absorption
Education: Chew tablets thoroughly then take with 8 oz water or milk
Frequency of administration makes compliance difficult
Prostaglandin E Analog
N203
ATI (Unit 10)
Digestion and Nutrition -
Expected Action: Proto: misoprostol (Cytotec)
acid secretion / secretion of HCO3- and mucus / submucosal vasodilation.
Therapeutic Uses: Long-term NSAID therapy
Induce labor by causing cervical ripening.
Adverse Effects: Diarrhea and abdominal pain Dysmenorrhea and spotting
Contraindications/Precautions: ♀ (X) Potential to become pregnant
Antiemetics
(Types)
N203
ATI (Unit 10)
Digestion and Nutrition -
Serotonin antagonists........................................................ondansetron (Zofran)
Dopamine antagonists........................................prochlorperazine (Compazine)
Glucocorticoids dexamethasone (Decadron)
Cannabinoids dronabinol (Marinol)
Anticholinergics scopolamine (Transderm Scop)
Antihistamine dimenhydrinate (Dramamine)
Others
Granisetron (Kytril)
Promethazine (Phenergan)
Metoclopramide (Reglan)
Hydroxyzine (Vistaril)
Aprepitant (Emend)
Antiemetics
(Action, Use, Effects, Interactions)
N203
ATI (Unit 10)
Digestion and Nutrition -
Agent: Action Use
Ondansetron SERR in CTZ & vagal nerve Chemo, radiation, postop
Prochlorperazine DOPR in CTZ Chemo, opioids, postop
Dexamethasone Unknown VC = Combo for chemotherapy
Dronabinol Unknown vomiting center Chemotherapy (CINV)
Scopolamine impulses: inner ear VC Motion sickness
Dimenhydrinate HISR MUSR inner ear VC Motion sickness
Agent Adverse Effect
Ondansetron Headache, diarrhea, dizziness
EPS (Tx ĉ Benadryl or Ativan), hypotension, sedation, and
Prochlorperazine
anticholinergic effects.
Dronabinol Dissociation, dysphoria, hypotension, tachycardia
AntiCh, AntiHis Sedation, anticholinergic effects
Interactions CTZ = chemoreceptor trigger zone
CNS depressants / Antihypertensives / Anticholinergics Additive Effects
Antagonists ĉ urinary retention, asthma, and narrow-angle glaucoma
Combo therapy allows lower doses of each side effects
Laxatives
N203
ATI (Unit 10)
Digestion and Nutrition -
Agent: Action Use
Bulk-forming Soften mass, bulk – same as diarrhea, control stool, promote
{psyllium} dietary fiber. defecation
Surfactant Opioids, pain, straining, risk
H2O content
{docusate} impaction, promote defecation
Stimulant peristalsis, H2O absorption Colonoscopy prep, short-term Tx
{bisacodyl} ( colon, intestine) d/t opioid use
Osmotic intestine H2O mass
Chemotherapy (CINV)
{Mg(OH) 3} stretching peristalsis
Agent Adverse Effect
All GI irritation
All Rectal burningproctitis ( regular use of bisacodyl suppository)
Mg2+ salts Accumulate toxic levels of magnesium ( in renal dysfunction)
Na+ salts Accumulation: in heart disease and hypertension
Interactions Milk & antacids destroy enteric coating
Fecal impaction / bowel obstruction / ulcerative colitis / diverticulitis
Promote fiber foods and > 1.5 L daily
Antidiarrheals
N203
ATI (Unit 10)
Digestion and Nutrition -
Proto: diphenoxylate (Lomotil)
Expected Action: Others: loperamide (Imodium), difenoxin (Motofen)
Activate opioid receptors in GI to motility and absorption of & Na+
Adverse Effects: At recommended doses, diphenoxylate has no CNS effects
diphenoxylate doses typical opioid responses
Contraindications/Precautions: ♀ (?)
risk of megacolon with inflammatory bowel disorders serious complications
including perforated bowel.
Interactions: CNS depressants depressive effect
Education: Encourage use of electrolyte replacement drinks
Avoid plain water (no electrolytes) and caffeine ( motility)
Manage dehydration (weight, VS, I&O) – 0.45% NS may be prescribed
Prokinetic Agents
N203
ATI (Unit 10)
Digestion and Nutrition -
Expected Action: Proto: metoclopramide (Reglan)
dopamine and serotonin receptors in CTZ emesis
Augments action of acetylcholine to upper GI motility
Therapeutic Uses: Postop and chemo-induced nausea and vomiting
GERD Diabetic gastroparesis
Adverse Effects: EPS: Restlessness, spasms of face & neck. Minimize Diarrhea
Sedation EPS with benzodiazepine like lorazepam (Ativan).
Contraindications/Precautions: ♀ (?) Seizure disorder ( seizure risk)
GI perforation or bleeding, bowel obstruction, and hemorrhage
Kids and older adults due to risk of EPS
Interactions: Concurrent EtOH or CNS depressant: seizure / sedation risks
Opioids and anticholinergics effects of metoclopramide.
Education: Dose ≥ 10 mg dilute in 50 mL D5W or Ringer’s; Infuse over 15m
