Expected Action:

Proto: ranitidine (Zantec) — Others: cimetidine (Tagamet), 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:

·  dec. libido / impotence

·  CNS effects (lethargy, depression, confusion) - inc. frequent in elderly ĉ renal or liver dysfunction.

Contraindications/Precautions:

♀ (B)

[image]    

[image]   inc. risk of bacterial colonization of stomach and respiratory tract

Interactions:

·   

·  Warfarin, phenytoin – metabolizing enzymes inhibited by cimetidine - inc. levels

·  Concurrent use of antacids dec. absorption H₂-receptor antagonists

Education:

·  Stop drinking, stop smoking, eat smaller, more frequent meals

·  Ranitidine can be taken without regard to food

Expected Action:

Proto: omeprazole (Prilosec) — Others: pantoprazole (Protonix), lansoprazole (Prevacid), esomeprazole (Nexium)

·  dec. 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)

·   

[image]   inc risk pneumonia d/t  inc. pH promoting bacterial colonization

Interactions:

·   

·  Delayed absorption of Ampicillin, digoxin, iron, ketoconazole if concurrent

Education:

·   

·  IV pantoprazole may cause thrombophlebitis, headache, or diarrhea.

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 fluids and inc. fiber

Contraindications/Precautions:

♀ (B)

[image]    

Interactions:

·  Antacids interfere with absorption of sucralfate.

·  ò absorption of phenytoin, digoxin, warfarin, ciprofloxacin

Education:

·  Take on empty stomach, 4x per day

Expected Action:

Proto:Al(OH)₃ gel (Amphojel), Others: AlCO₃, 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)3-hypophosphatemia

·  Mg2+ compounds - toxicity with renal impairment.

Contraindications/Precautions:

♀ (C)

[image]   GI perforation or obstruction

Interactions:

·   

·  Aluminum-compounds bind to warfarin, tetracycline and dec. their absorption

Education:

·  Chew tablets thoroughly then take with 8 oz water or milk

·  Frequency of administration makes compliance difficult

Expected Action:

Proto: misoprostol (Cytotec)

·  dec. acid secretion / inc. secretion of HCO₃^- and mucus / dec. 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)

[image]   Potential to become pregnant

Agent:

Action

Use

Ondansetron

 SER_R in CTZ & vagal nerve

Chemo, radiation, postop

Prochlorperazine

DOP_R in CTZ

Chemo, opioids, postop

Dexamethasone

Unknown

Combo for chemotherapy

Dronabinol

Unknown

Chemotherapy (CINV)

Scopolamine

 impulses: inner ear - VC

Motion sickness

Dimenhydrinate

HIS_R MUS_R inner ear - VC

Motion sickness

Agent

Adverse Effect

Ondansetron

Headache, diarrhea, dizziness

Prochlorperazine

EPS (Tx ĉ Benadryl or Ativan), hypotension, sedation, and anticholinergic effects.

Dronabinol

Dissociation, dysphoria, hypotension, tachycardia

AntiCh, AntiHis

Sedation, anticholinergic effects

Interactions

·  CTZ = chemoreceptor trigger zone

·  CNS depressants / Antihypertensives / Anticholinergics - Additive Effects

[image]   Antagonists ĉ urinary retention, asthma, and narrow-angle glaucoma

·  Combo therapy allows lower doses of each \ dec. side effects

Agent:

Action

Use

Bulk-forming

{psyllium}

Soften mass, inc bulk – same as dietary fiber.

dec. diarrhea, control stool, promote defecation

Surfactant

{docusate}

inc. H₂O content

Opioids, pain, straining, dec. risk impaction, promote defecation

Stimulant

{bisacodyl}

inc. peristalsis, H₂O absorption (dec. colon, inc. intestine)

Colonoscopy prep, short-term Tx d/t  inc. opioid use

Osmotic

{Mg(OH) ₃}

inc. intestine H₂O ’= inc mass =’ stretching =’inc. peristalsis

Chemotherapy (CINV)

Agent

Adverse Effect

All

GI irritation

All

Rectal burning=’proctitis (D regular use of bisacodyl suppository)

Mg²⁺ salts

Accumulate toxic levels of magnesium ([image] in renal dysfunction)

Na⁺ salts

Accumulation: [image] in heart disease and hypertension

Interactions

·  Milk & antacids destroy enteric coating

[image]   Fecal impaction / bowel obstruction / ulcerative colitis / diverticulitis

·  Promote inc. fiber foods and > 1.5 L S daily

Expected Action:

Proto: diphenoxylate (Lomotil)

Others: loperamide (Imodium), difenoxin (Motofen)

·  Activate opioid receptors in GI to dec. motility and inc. absorption of water & Na⁺

Adverse Effects:

·  At recommended doses, diphenoxylate has no CNS effects

·  inc. diphenoxylate doses=’ typical opioid responses

Contraindications/Precautions:

♀ (?)

·   

·  inc. risk of megacolon with inflammatory bowel disorders =’ serious complications including perforated bowel.

Interactions:

·  CNS depressants inc. depressive effect

Education:

·  Encourage use of electrolyte replacement drinks

·  Avoid plain water (no electrolytes) and caffeine (inc. motility)

·  Manage dehydration (weight, VS, I&O) – 0.45% NS may be prescribed

Expected Action:

Proto: metoclopramide (Reglan)

·   dopamine and serotonin receptors in CTZ \dec emesis

·  Augments action of acetylcholine to ñ upper GI motility

Therapeutic Uses:

·  Postop and chemo-induced nausea and vomiting

·  GERD

·  Diabetic gastroparesis

Adverse Effects:

·  EPS: Restlessness, spasms of face & neck. Minimize EPS with benzodiazepine like lorazepam (Ativan).

·  Diarrhea

·  Sedation

Contraindications/Precautions:

♀ (?)

[image]   Seizure disorder (ñ seizure risk)

[image]   GI perforation or bleeding, bowel obstruction, and hemorrhage

[image]   Kids and older adults due to inc. risk of EPS

Interactions:

·  Concurrent EtOH or CNS depressant: inc. seizure / sedation risks

·  Opioids and anticholinergics dec. effects of metoclopramide.

Education:

·  Dose ≥ 10 mg ’ dilute in 50 mL D₅W or Ringer’s; Infuse over 15m