Lec 17: Digestive system, Acid-controlling, Antiemetics, Bowel drugs

Lec 17

H₂ receptor agonists = -______

-tidine

• Famotidine

Proton pump inhibitors (PPIs) = -_______

-prazole

• Omeprazole

Antacids =

No consistent suffix

• Calcium carbonate

• Magnesium hydroxide

• Sodium bicarbonate

GI Protectants =

No consistent suffix

• Sulcrafate

Prostaglandin Analogs = -_______

-prostol

• Misoprostol

Antiemetics (Serotonin antagonists) = -______

-setron

• Ondansetron

Antiemetics (Prokinetics) =

No consistent suffix

• Metoclopramide

What are the types of acid controlling drugs?

• Antacids

• H2 Antagonists

• Proton Pump Inhibitors (PPIs)

What is the basic compound used to neutralize stomach acid?

Antacids

What do antacids promote?

Gastric mucosal defense mechanisms

Antacids stimulate the secretion of

• M____:

• B__________:

• P___________:

What do each of these do?

• Mucus: protective barrier against HCL

• Bicarbonate: helps buffer acidic properties of HCL

• Prostaglandins: prevent activation of proton pump

What drugs would you use for GERD and PUD?

Antacids

Antacids offer _____ relief of symptoms

acute

Antacids can be used alone or in combination, in which instances would it be used in combination and why?

• Antiflatulent drug simethicone

• Aluminm + Calcium based formulas also include magnesium

  • Magnesium contributes to acid neutralizing + help counteract constipating effects of alumnum + calcium

Antacids: Aluminum salts

• Example

• Indication

• Side effects

• Special considerations

• E: Maalox

• I: GERD, Heartburn, Peptic Ulcer Disease, Gastritis

• SE: Constipation, Hypophosphatemia (manifests as anorexia, malaise, tremors, muscle weakness)

• SC: Aluminium toxicity with prolonged use, Often recommended with renal disease (more easily excreted)

Antacids: Calcium salts

• Example

• Indication

• Side effects

• Special Considerations

• E: Calcium carbonate (TUMS)

• I: GERD, Heartburn relief, Calcium supplementation

• SE: Constipating, Hypercalcemia, Hypophosphatemia, Metabolic alkalosis

• SC: May lead to development of kidney stones (hypercalcemia)

Maalox: Therapeutic/Pharmacologic class?

Antacid

Maalox: Contains?

• Aluminum hydroxide

• Magnesium hydroxide

• Simethicone (antiflatulant)

Maalox: Actions?

• Neutralizes gastric acid

• Promote gastric mucosal defense mechanisms

• Anti-gas

Maalox: Indicated for?

• Peptic Ulcer Disease, GERD, Gas pain, Heartburn relief

Maalox: Contraindicated in?

• Renal impairment

  • Hypermagnesemia / aluminum toxicity

    • Cannot clear Magnesium or Aluminium

Maalox: Most common adverse effetcs?

• GI: Constipation, Decreased GI motility, Hemorrhoids, Stomach cramping

Maalox: Most serious adverse effects?

• Prolonged use can cause hypophosphatemia

  • Aluminum binds to and decreases phosphate absorption

Maalox: Special considerations?

• Avoid aluminum antacids in infants / young pediatric patients with renal impairment

Maalox: Administration?

• Route: Oral (liquid, suspension, tablet)

  • Suspension = shake 1 hr before taking

  • 1 hr before meals (best on empty stomach)

Maalox: Assessments during use?

• Monitor for relief of GERD/Ulcer symptoms (heartburn)

• Assess medical history: Renal impairment

• Monitor for abdominal pain, distension, tenderness

Maalox: Pt/family teaching?

• Take 1 hr before meals

• Avoid taking more than directed

What may restrict the use of antacids?

• Fluid imbalances

• Renal disease

• GI obstruction

• Heart Failure

• Pregnancy

Patients with what should not use antacids with high sodium content?

• Heart failure

• Hypertension

Most medications should be administered 1 to 2 hours _____ an antacid

after

What do acid-controlling drugs do?

Suppresses acid secretion in the stomach

Acid-controlling drugs: Histamine (H2) Receptor Antagonist

• Inhibits?

• What decreases effectiveness?

• For optimal results?

• Suffix?

• Inhibits histamine at H2 receptors within gastric parietal cells —> inhibits gastric acid secretion

• Smoking decreases effectiveness of H2 blockeers

• For optimal results, H2 receptor antagonists are taken 1-2 hours before antacids

• -tidine

Acid-controlling drugs: Proton Pump Inhibitors

• Inhibits?

• Suffix?

• Inhibits parietal cells which release positive hydrogen ions during HCL production —> suppresses gastric acid secretion

• -prazole

Famotidine: Therapeutic class?

Antiulcer agent

Famotidine: Pharmacologic class?

Histamine-2 Receptor Antagonist (H2 Blocker)

Famotidine: Actions and uses?

• Selectively blocks H2 receptors in the stomach lining which decreases gastric acid secretion and concentration of hyrodgen ions

• Promotes healing of ulcers and reduces irritation from acid reflux

Famotidine: Indications?

• Peptic ulcers (gastric + duodenal)

• GERD

• Heartburn, Indigestion, Sour stomach (OTC use)

• Prevention of stress-induced ulcers in critically ill patients

Famotidine: Contraindications?

• Hypersensitivity

• Renal impairment caution

  • Drug = renally excreted, so dose may need adjustment

• Elderly caution

  • Increased risk of CNS effects

Famotidine: Most common adverse effects?

• CNS: HA, Dizziness, Fatigue, Confusion

• GI: Constipation, Diarrhea, Nausea

• DERM: Rash, Pruritus

Famotidine: Most serious adverse effects?

• Heme: Rare bone marrow suppression

• CNS: Hallucinations, Seizures

• CARDIAC (IV USE): Arrhythmias, Hypotension with rapid infusion

Famotidine: Special considerations?

• Avoid long term use without medical supervision

• For IV infusion, give slowly equal/longer than 2 minutes

Famotidine: Administration?

• Routes: PO, IV, IM

• May be taken with/without food

• For ulcers: Give at bedtime to suppress nocturnal acid secretion

• Available OTC for heartburn/indigestion at lower doses

Famotidine: Assessent during use?

• Monitor relief of GERD/Ulcer symptoms

• Assess for confusion, dizziness, HA

• Monitor CBC with prolonged therapy

Famotidine: Pt/family teaching?

• Take as directed even if not feeling better, do not double doses if one is missed

• Avoid smoking, alcohol, caffeine, and NSAIDs

• Report black/tarry stools, coffee ground emesis, or persistent abdominal pain

• Notify provider if confusion, dizziness, or irregular heartbeat

• Discuss with provider if needed over 2 weeks

Omeprazole: Therapeutic class?

Antiulcer agent

Omeprazole: Pharmacologic class?

Proton pump inhibitor

Omeprazole: Actions and uses?

• Irreversibly inhibits H+/K+ ATPase in gastric parietal cells

• Suppresses the final step of gastric acid secretion —> profound + prolonged reduction in stomach acid

Omeprazole: Indications?

• Short term treatment of GERD

• Peptic ulcer disease

• Erosive esophagitis

• Zollinger Ellison syndrome and other hypersecretory symptoms

• Used with antibiotics for H. pylori eradication

  • Clarithromycin, Amoxicillin, Metronidazole

• OTC use: frequent heartburn (2 or more times/week)

Omeprazole: Contraindications?

• Hypersensitivity

• Hepatic impairment

• Long term therapy increases risk of complication

Omeprazole: Most common adverse effects?

• GI: N/V/D/C, abdominal pain, flatulance

• CNS: HA, dizziness, fatigue

• Resp: Upper respiratory infection symptoms (cough, pharyngitis)

Omeprazole: Most serious adverse effects?

• GI: Increased risk of C.diff-associated diarrhea

• Bone: Long-term use linked to osteoporosis-related fractures

• Nutritional: Vitamin B12 deficiency, hypomagnesemia with prolonged therapy

• Renal: Acute interstitial nephritis

• Immune: Hypersensitivity

Omeprazole: Special considerations?

• Use the lowest effective dose for shorest duration neccesary

• Monitor magnesium and vitamin B12 levels with long term therapy

• Has many drug interactions - amphetamines

Omeprazole: Administration?

• Route: PO, IV

• Take before meals preferably in the morning

• Swallow capsule/tablet whole, do not CRUSH or CHEW

  • Enteric coating to survive stomach acid

• May take several days for full symptom relief

• Therapy often limited to 4-8 weeks unless otherwise prescribed

• H. pylori treatment always used in combo with antibiotics

Omeprazole: Assessment during use?

• Monitor for GERD/Ulcer symptom relief

• Assess for abdomial pain, diarrhea, persistent GI symptoms (possible C.diff)

• Monitor magnesium, vitamin B12, bone density

• Evaluate liver function if prolonged use / high dose therapy

Omeprazole: Pt/family teaching?

• Take medication 30-60 minutes before eating

• Do not self treat chronic heartburn beyond 14 days OTC without evaluation

• Report persistent diarrhea, abdominal pain, black/tarry stools (C.diff, GI bleed)

• Stress importance of completing antibiotic regimen if prescribed for H. pylori

• Long term users should ensure adequate Calcium + Vitamin D intake

Compare: Antacids, H2 Blockers, PPIs

• Suffix

• Onset

• Duration

• Mode of Action

• Examples

• Best for

• Concerns

• None, -tidine, -prazole

• Minutes, 30-60 minutes, 1-2 days for full effects

• Short (1-3hr), 6-12hr, up to 24 hr

• Neutralize existing acid, Block histamine at H2 receptors to decrease acid, Irreversibly block proton pump to decrease acid

• TUMS / Maalox, Famotidine (pepcid), Omeprazole

• Quick symptom relief (heartburn), Mild-moderate GERD/Ulcers, Severe GERD/PUD/Erosive esophagitis

• C/D/Metabolic alkalosis, CNS effects in elderly/Renal dosing, Longterm= fractures/C.diff/B12 deficiency

GI Mucosal Protectant?

Misoprostol

Misoprostol: Therapeutic class?

• Antiulcer agent

• Cytoprotective agent

Misoprostol: Pharmacological class?

Prostaglandin E1 analog

Misoprostol: Action and uses?

• Binds to prostaglandin receptors on gastric parietal cells

  • Increases bicarbonate + mucus production in stomach lining

• Reduces gastric acid secretion

• Helps prevent/heal NSAID induced gastric ulcers

Misoprostol: Indication?

• Prevention of NSAID induced gastric ulcers in high risk patients

• Off label: Induction of labor + management of postpartum hemorrhage

Misoprostol: Contraindication?

• Pregnancy (category X) —> Causes contractions, miscarriage, congenital manisfestations

• Hypersensitivity

Misoprostol: Most common adverse effects?

• GI: D/N, Abdominal pain, cramping, faltulence

• GU: Spotting, dysmenorrhea in women

Misoprostol: Most serious adverse effects?

• OB: Uterine rupture (when used to induce labor, especially in women with prior c section)

• Immune: hypersensitivity

Misoprostol: Special considerations?

• Use effective contraception!

• Should be discontinued if pregnancy suspected

• Combined with mifepristone for medical termination of pregnancy

Misoprostol: Administration?

• PO (tablet)

• For ulcer prevention = take with meals at bedtime

• Always given with NSAID therapy in high risk patient to protect stomach

Misoprostol: Assessment during use?

• Monitor for GI effects

• In women = pregnancy status before use

Misoprostol: Pt/family teaching?

• Take exactly as prescribed, with food

• Report severe diarrhea, abdominal pain, vaginal bleeding

• Use reliable contraceptive

What are the types of Anti-emetic/Anti-nausea drugs?

• Antihistamines (Histamine 1 receptor blocker)

• Prokinetic drugs

• Serotonin blockers

What are anti-emetic/anti-nausea drugs for?

Reduce nausea/vomitting

Anti-emetic/Anti-nausea drugs: Antihistamine drugs

• Inhibits

• Prevent

• Also used for

• Inhibits acetylcholine (Ach) by binding to H1 receptors

• Prevents cholinergic stimulation in vestibular/reticular areas to prevent N/V

• Also used for motion sickness, nonproductive cough, allergy symptoms, sedation

Anti-emetic/Anti-nausea drugs: Prokinetic drugs

• Blocks

• Stimulates

• Used for

• Blocks dopamine receptors in chemoreceptor trigger zone (CTZ)

  • Cause CTZ to desensitize to impulses from GI tract

• Stimulate peristalsis in GI tract

  • Enhancing empyting of stomach contents

• Used for GERD, delayed gastric emptying (tube feeds)

Anti-emetic/Anti-nausea drugs: Serotonin blockers

• Prevent

• Often used for

• Prevent the reuptake / block the action of serotonin in serotonin receptors in the GI tract, CTZ, and vomitting center

• Often used for N/V in patients recieving chemotherapy or postop

Metoclopramide: Therapeutic class?

Antiemetic

Metoclopramide: Pharmacological class?

Prokinetic

Metoclopramide: Actions and uses?

• Block dopamine receptors in chemoreceptor trigger zone (CTZ)

  • Cause CTZ to be desensitized to impulses from GI tract

• Stimulates peristalsis in GI tract

Metoclopramide: Indication?

• GERD when failed traditional therapy

• Chemotherapy induced N/V

• Postop nausea

Metoclopramide: Common adverse effects?

• GI: Abdominal cramps, diarrhea

• Extrapyramidal symptoms: acute dystonia, pseudo parkinsons

Metoclopramide: Serious adverse effects?

• CNS toxicity: restlessness, fatigue, drowsiness, depression

• Tardive Dyskinesia with chronic use + irreversible

Metoclopramide: Special considerations?

• Females: Hyperprolactinemia / Galactorrhea (increased milk production)

• Males: Gynecomastia, erectile dysfunction

Metoclopramide: Administration?

• Oral (tablet, solution)

• IV, IM, Inranasal

  • IV = direct push / continuous infusion

Metoclopramide: Assessment during use?

• Monitor for neurological changes

• Monitor for improved N/V

Metoclopramide: Pt/family teaching?

• Take exactly as prescribed, 30 mins before meals

• Report depression, restlessness, uncontrollable movements

Ondansetron (ZOFRAN): Therapeutic class?

Antiemetic

Ondansetron (ZOFRAN): Pharmacological calss?

Selective 5-Ht₃ receptor antagonist

Ondansetron (ZOFRAN): Actions and uses?

• Blocks the action of serotonin by binding to the serotonin receptors

• Stops the transmission at receptors in the CTZ, vomitting center and GI tract

Ondansetron (ZOFRAN): Indications?

• GERD when traditional therapy fails

• Chemotherapy induced N/V

• Postop Nausea

Ondansetron (ZOFRAN): Contraindications?

• Some neurological disorders (parkinsons)

• Not used for >12 weeks

Ondansetron (ZOFRAN): Most common adverse effects?

• GI: Abdominal cramps, Diarrhea

• CNS: HA

• Extrapyramidal: Acute dystonia, pseudo parkinsons

Ondansetron (ZOFRAN): Most serious adverse effects?

• Cardiac: Arrhythmias (QT Prolongation)

• Seotonin syndrome

  • Nervous system

  • Skin flushing, muscle rigidity, hyperthermia, agitation, seizure, coma

  • Can occur with ondansetron + antidepressants

Ondansetron (ZOFRAN): Special considerations?

• Avoid in patients with increased risk for prolonged QT prolongation

• Caution with electrolyte abnormalities

Ondansetron (ZOFRAN): Administration?

• Oral, IV, IM, Intransal

Ondansetron (ZOFRAN): Assessment during use?

• Monitor neurological changes

• Monitor for improvement N/V

Ondansetron (ZOFRAN): Pt/family teaching?

• Take exactly as prescibed 30 minutes before meals

• Report depression, reestlessness, uncontrollable movements

What are the types of Bowel-Disorder Drugs?

• Antidiarrheals

• Laxatives

Goals of Diarrhea treatment:

• Stopping

• Alleviating

• Replenishing

• Preventing

• Stopping stool frequency

• Alleviating abdominal cramps

• Replenishing fluids and electrolytes

• Preventing weight loss and nutritional deficits from malabsorption

What are anti-diarrheals used for?

Reduce frequency of diarrhea

Antidiarrheals: Adsorbents

• Coat

• Bind

• Used in

• Coat the walls of the GI tract

• Bind to the causative bacteria/toxin which is then eliminated through the stool

• Used in more mild cases

Antidiarrheals: Antimotility drugs

• Used in

• Decreases + Reduce

• Decreases + absorption

• Used in more severe cases

• Decreases bowel motility + Reduces pain by relief of rectal spasms

• Decreases transit time through the bowel + Allowing more time for water and electrolytes to be absorbed

Bismuth Subsalicylate: Therapeutic class?

Anti-diarrheal