Chapter 10

Drugs for Gastrointestinal and Related Diseases

Chapter 10 Definitions

• Gastrointestinal (GI) tract• GI transit time• GERD• Peptic Disease• Ulcer

The Gastrointestinal System

• Gastrointestinal (GI) tract is a continuous tube

• Starts at mouth pharynx esophagus stomach small intestine large intestine ends at anus

• Digestive and absorptive process take place in the GI tract

GI Transit Time

• Speeding up transit time = less absorption

• Slowing transit time = more absorption

Gastroesophageal Reflux Disease (GERD)

• Symptoms– Radiating burning or pain in chest– Acid taste– Recurrent abdominal pain

• Meal-related esophagitis due to reflux (backflow) of acidic stomach contents through incompetent esophageal sphincter

H2 Histamine Receptor Antagonists

• Block gastric acid and pepsin secretion

• Blocks action of histamine in the stomach- decreasing the production of acid

• All available OTC in some strengths

• Bedtime dose is most important

Therapeutic Uses of ranitidine (Zantac, Zantac 75)

• Active duodenal ulcers and benign gastric ulcers

• Long-term prevention of duodenal ulcers

• Gastric hypersecretory states• GERD• Postoperative ulcers• Preventing stress ulcers• Upper GI bleeding

Therapeutic Uses of ranitidine (Zantac, Zantac 75)

• Precautions:– Pregnancy-B– Do not crush, chew or break

• Side-Effects:– Increase risk of Pneumonia– HA, dizziness, insomnia, decreased

sex drive, swollen breast-men, nausea, vomiting, diarrhea, constipation

Dispensing Issues of Ranitidine

Look-alike and sound-alike – Ranitidine (H2 antagonist)– Amantadine (for flu) – Rimantadine (antiviral)

Dispensing Issues of Zantac

• Look-alike and sound-alike– Zantac– Xanax (antianxiety)

Proton Pump Inhibitors

• An enzyme maintains acidity in gastric secretions by pumping– Acidic hydrogen ions (protons) into

stomach– Nonacidic potassium ions out

• Proton pump inhibitors (PPIs) block this enzyme, reducing stomach acidity

• PPIs must be taken daily

omeprazole (Prilosec)

• Indicated for short-term treatment of esophagitis, GERD, and hypersecretory conditions

• Take before meals• Also indicated for peptic disease

caused by bacterium Helicobacter pylori (H. pylori)

omeprazole (Prilosec)

• Precautions:– Pregnancy Cat C– Do not crush, chew or break

• Side Effects:– Fever– Cold symptoms– Stomach pain– Nausea, vomiting, diarrhea– headache

lansoprazole (Prevacid)

• Indicated for short-term therapy of ulcers and esophagitis

• Indicated for long-term treatment of hypersecretory disorders and Zollinger-Ellison syndrome (hypersecretion from a tumor)

lansoprazole (Prevacid)

• Not for immediate relief of heartburn

• Precautions: – 1Q24H for 14days, 4 months between

treatments– Pregnancy Cat. B– Do not crush, chew or break

• Side Effects:– Headache, nausea, stomach pain,

diarrhea, constipation

esomeprazole (Nexium)

• Very similar to Prilosec, but metabolized slower which increases duration of acid suppression

• Take on an empty stomach

esomeprazole (Nexium)

• Not for immediate relief of heartburn• 4-8 weeks full glass of water, 1 hr

before food• Precautions:

– Severe liver disease, low levels of magnesium

– Pregnancy Cat B• Side Effects:

– Headache, drowsiness, diarrhea, nausea, stomach pain, constipation, dry mouth

Agents for GERDCombinations – calcium carbonate-famotidine-

magnesium hydroxide (Pepcid Complete)

– lansoprazole-naproxen (Prevacid NapraPAC)