Pharm exam 1 - GI drugs

Gastroesophageal Reflux Disease - pathophysiology

• Failure of lower esophageal sphincter to contract properly
• Regurgitation of stomach contents into esophagus

What are the risk factors for GERD

• Hiatal hernia
• Esophageal defects
• BMI
• Pregnancy

What is Peptic ulcer disease (PUD) ?

Varying degrees of erosion to stomach or proximal duodenum

What are the causes of PUD?

Cause: Aggressive factors outweigh defensive factors

◦ Gastric acid must be present for an ulcer to form

What are the most common symptoms of PUD?

◦ Dyspepsia
◦ Epigastric pain / “burning”
◦ Fullness, bloating, nausea, early satiety

PUD aggressive factors

• H. Pylori

• NSAIDs

• Acid

• Pepsin

• Smoking

PUD defensive factors

• mucus

• bicarbonate

• blood flow

• prostaglandins

What is the most common cause of PUD?

the bacteria: H. Pylori (Helicobacter pylori)

Medications to treat PUD and GERD

Class
Antibiotics (for PUD)
Histamine-2 receptor antagonists (H2 blockers)
Proton pump inhibitors (PPI)
Mucosal protectant (sucralfate)
Antacids

What is triple therapy?

2 antibiotics + H2 blocker or PPI

What is quadruple therapy?

2 antibiotics + H2 Blocker or PPI + bismuth

What patients with PUD receive antibiotics?

All patients with PUD who test positive for H. pylori

*multiple antibiotics are needed

What are the antibiotic options for PUD?

◦ Clarithromycin (-mycin = macrolide class)
◦ Amoxicillin (-cillin = penicillin class)
◦ Tetracycline (-cycline = tetracycline class)
◦ Bismuth (pepto-bismol in the pink bottle, OTC)
◦ Metronidazole (Misc class)

What is Cimetidine (end in –dine)?

Histamine2 receptor antagonists (H2RA or H2 Blockers)

It works by blocking histamine in the stomach, effectively reducing the production of gastric acid

*available over the counter (OTC)

What is the MOA for Cimetidine?

Selectively blocks the histamine 2 receptors in the stomach, which reduces volume and acidity of gastric acids by 80%

What is the pharmacokinetics for Cimetidine?

Short T1/2 (2 hours)

What do we use Cimetidine for?

◦ Gastric and duodenal ulcers
◦ GERD
◦ Ulcer prophylaxis

What are the adverse effects of Cimetidine?

◦ BBB →CNS disturbances
◦ elderly
◦ renal impairment

What is Omeprazole (end in –prazole)?

Proton Pump Inhibitors (PPIs)

an oral medication that belongs to a class of drugs called Proton Pump Inhibitors (PPIs)

What is the MOA for Omeprazole?

Irreversibly inhibits the enzyme ATPase that makes gastric acid

What is Omeprazole most effective for?

suppressing gastric acid production by 97%

What are the uses for Omeprazole?

◦ Short-term use (4-8 weeks)
◦ Gastric or duodenal ulcers
◦ Standard treatment for H. pylori
◦ GERD or dyspepsia

What are the adverse effects for Omeprazole?

◦ 3+ months of treatment: Magnesium deficiency
◦ 12+ months of treatment: osteoporosis, bone fractures
◦ 36+ months of treatment: B12 deficiency
◦ Rebound acid hypersecretion
◦ Available OTC!

What is the MOA for SucralfatevMucosal protecting agent

Reacts with stomach acid to form viscous gel that coats the stomach lining

How does sucralfate mucosal protecting agent promote healing?

by creating a protective barrier between the ulcer and the stomach acid

What does sucralfate mucosal protecting agent inhibit?

pepsin, which breaks down proteins (prevents worsening of the ulcer)

What do we use sucralfate mucosal protecting agent for?

Acute and chronic ulcer treatment

Are there significant systemic adverse effects for sucralfate mucosal protecting agent?

No because there is minimal systemic absorption

What are the interactions for sucralfate mucosal protecting agent?

◦ Requires gastric pH <4 to work, so antacids that increase gastric pH may decrease effectiveness of sucralfate
◦ Impairs absorption of some drugs when given together (wait > 2 hours)

What are Antacids?

Alkaline compounds that neutralize or at least raise the pH of gastric acid

What is the MOA of antacids?

direct interaction with hydrogen ions in gastric acid

What are the uses of Antacids?

PUD & GERD (symptom relief)

What are the different types of antacids?

Aluminum, magnesium, calcium, and sodium compounds

What are the adverse effects of antacids?

◦ Calcium and Aluminum = constipation
◦ Magnesium = diarrhea

What is Misoprostol Prostaglandin analog?

A mucosal defense-enhancing agent

What is the MOA for Misoprostol Prostaglandin analog

is a synthetic replacement for endogenous prostaglandins

What are the uses for Misoprostol Prostaglandin analog?

only approved for prevention of NSAID-induced gastric ulcers

What are adverse effects of Misoprostol Prostaglandin analog?

◦ Diarrhea, abdominal pain or cramps
◦ Contraindicated in pregnant women
◦ may cause expulsion of fetus
◦ Teratogenic

What are the nursing considerations for H2 blockers?

• Without regard to meals
•Elderly: CNS effects (confusion, dizziness)

What are the nursing considerations for PPIs?

• Before meals
• Short term use
• Watch for vitamin deficiencies (mag, cal, B12)

What are the nursing considerations for sucralfate?

• 1 hour before meal, other meds 2 hrs after

What are the nursing considerations for antacids?

• 1 hour before or after taking other meds (to minimize drug interactions)
• Ca-based: avoid in hypercalcemia, kidney stones
• Mag-based: avoid in renal disease

What are the nursing considerations for misoprostol?

• after meals (to minimize GI upset)
• Contraindicated in pregnancy

Antibiotics therapeutic use?

Cure H. pylori infection

Histamine-2 receptor antagonists (H2 blockers) prototype:

Cimetidine

Histamine-2 receptor antagonists (H2 blockers) therapeutic use:

Suppress acid secretion for healing, symptom management, prevent recurrence

Proton pump inhibitors (PPI) prototype:

Omeprazole

Proton pump inhibitors (PPI) therapeutic use:

Suppress acid secretion for healing, symptom management, prevent recurrence

Mucosal protectant prototype:

Sucralfate

Mucosal protectant therapeutic use:

Barrier to protect mucosa, symptom management, prevent recurrence

Mucosal defense enhancer prototype:

Misoprostol

Mucosal defense enhancer therapeutic use:

Stimulates secretion of mucus and bicarbonate; maintain submucosal blood flow to protect and prevent recurrence, symptom management

Antacids prototype:

Aluminum hydroxide, magnesium hydroxide, calcium carbonate, sodium bicarbonate

Antacids therapeutic use:

Neutralizes gastric acid, symptom management, prevent damage

What is constipation?

• Hard or infrequent stools
• Excessive straining or prolonged effort to produce bowel movement
• Incomplete evacuation or inability to produce bowel movement

What are the goals of treatment for constipation?

• Soften stools
• Increase stool volume
• Increase GI motility to hasten fecal passage through intestines
• Facilitate evacuation from rectum

How many types / groups of laxatives are there?

3

What type of stool does group 1 produce?

Produce watery stool in 2-6 hours

What are group 1 osmotic laxative doses?

◦ Osmotic laxatives in high doses (magnesium citrate, polyethylene glycol aka Miralax)
◦ Others (castor oil)

What type of stool does group 2 produce?

Produce semifluid stool in 6-12 hours

What are group 2 osmotic laxative doses?

◦ Osmotic laxatives in low doses (mag citrate, polyethylene glycol aka Miralax)
◦ Stimulant laxatives (Bisacodyl aka Dulcolax, Ex-Lax Ultra and Senna aka Ex-Lax, Senokot)

What type of stool does group 3 produce?

Produce soft stool in 1-3 days

What are the different types of lactatives for group 3?

◦ Bulk forming laxatives (methylcellulose aka Citrucel, psyllium aka Metamucil,
polycarbophil aka Fibercon)
◦ Surfactant laxatives (docusate sodium)
◦ Lactulose

docusate sodium (Colace) Surfactant Laxative MOA:

Allows more water into the stool to give it more volume and make it softer

docusate sodium (Colace) Surfactant Laxative goal of treatment:

Produce soft stool in 1-3 days

Nursing considerations for docusate sodium (Colace) Surfactant Laxative:

Nurse’s role is to EDUCATE!
◦ Poor diet, fluid intake & low activity is a common cause of constipation.
◦ Increase dietary fiber (whole grains, fresh fruits & vegetables)
◦ Increase daily water intake
◦ Exercise can promote normal bowel function
◦ Docusate sodium works slowly – do not expect an immediate
stool
◦ If needed, laxatives should be used only briefly and only in addition to improved diet, adequate hydration, and regular physical activity