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Week – 4 Pharmacology
Drugs
and Disorders of the
Gastrointestinal Tract
Nutritional Supplements
chapters – 25 and 20
GI TRACT – A DEFINITION
Long, hollow tube from the mouth to the anus
 primary purpose - to convert food into chemicals that can be
used by the body
 Food’s pathway through GI tract …
… Mouth  Esophagus  Stomach Small Intestines 
[gallbladder, liver, pancreas enzymes]Large Intestine Anus
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HOW DRUGS WORK IN THE GI SYSTEM

1. they increase or decrease function by changing muscle
tone, or changing the level of secretions (for example …
decreasing the level of acid-production to prevent or cure
ulcers)
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2. Increase or decrease ‘emptying time’ (the time it takes food
to pass through the stomach/GI tract) … this is accomplished
by altering ‘peristalsis’
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3. Replacement of enzymes (in cases of deficiency)
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LIFESTYLE MODIFICATIONS FOR GI
PROBLEMS

Foods to avoid
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Tomato
Orange/Grapefruit juice
ETOH
Caffeine
Chocolate
peppermint
Don’t over eat, maintain ‘normal’ weight
 Avoid eating within 2 hours of bedtime
 Don’t smoke
 Elevate head of the bed 6-8 inches (gravity can help empty the
stomach!)
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GASTRIC CONDITIONS/ENVIRONMENT
Acidic environment is needed in the stomach for enzymes to
work and inhibit or kill microorganisms found in food and
other materials that are ingested
 Sometimes acid level is too high and can erode the stomach
wall/lining
 Worry and Stress increase secretions in the stomach
 This can lead to ulcers
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Gastric ulcer = Peptic ulcer = stomach ulcer (all the same)
 ‘Deodenal ulcer’ is found at the junction of stomach and duodenum
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ULCERS – GENERAL INFO

Goal of treatment: to alleviate symptoms, promote healing
prevent complications, and prevent recurrence.
 Heliobacter pylori has been found in >75% of peptic ulcer
disease! (the remaining 25% caused by NSAID & ASA use)

Opportunistic infection at the site of the ulcer.
Smoking slows the healing of ulcers … it increases acid
production
 Eating multiple small meals decreases changing acid levels
 Drugs (ASA and NSAID’s) can cause irritation to the stomach
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MEDICATIONS TO TREAT ULCER

All these work together to eradicate the microorganism
Helicobacter pylori and reestablish an intact lining of the
stomach by neutralizing excess hydrochloric acid.
 Antacids (neutralizes acid that is currently present)
 Mucosal protectants (forms a protective barrier on the
surface of ulcerated tissue)
 Antibiotics
 Antisecretory Agents (reduce excess acid-production)
 Antispasmodics
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ANTACIDS
Alkaline compounds used to neutralize HCl acid in the stomach
 Used as prophylaxis for stress-induced ulcers
 Relieves symptoms of Gastroesophageal Reflux Disease (GERD)
 Protect intestinal mucosa by neutralizing acid
 Poorly absorbed (this is good!), therefore they do not alter
systemic pH when used properly

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ANTACIDS CONTINUED
More effective when taken on a regular basis
 Can be dosed up to 7 times per day (before meals, after meals,
and bedtime)
 Come in liquids, chew tabs, and a few swallow tabs or caps.
 Short duration of action … ~ 30 minutes on empty stomach
 Chronic use can produce acid rebound
 Classified by formulation (aluminum, magnesium, etc)
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ANTACID FORMULATIONS
Aluminum (side-effect = Constipation)
 Calcium (side-effect = Constipation)
 Magnesium (side-effect = Diarrhea)
 Sodium (can change systemic pH – dangerous choice)
 Aluminum & Magnesium combo is common because these
cancel out each other’s negative side-effects … very effective!
 Choose product with care, based on patient’s profile
 NOTE - sodium bicarbonate changes the pH (acid/base
balance) in the body and can lead to other problems
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PATIENT EDUCATION FOR ANTACIDS
Chewable antacids should be taken with a full glass of water
or milk to help with absorption
 Shake liquids well and don’t follow with additional liquids …
this dilutes the antacid, reducing its effect
 Antacids and H-2 blockers should be taken at least an hour
apart, antacids first.
 careful when taking other medications, these can interfere
with absorption of other drugs
 Examples of Antacids …

Mylanta, Maalox
 Tums, Rolaids
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ANTISECRETORY AGENTS
These Decrease the secretion of gastric fluids (acid)
 Two types

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H2-receptor antagonists (H2)
Zantac (ranitidine)
 Pepcid (famotidine)
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Proton pump inhibitors (PPIs)
Prilosec (omeprazole)
 Previcid (lansoprazole)
 Nexium (esomeprazole)
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* NOTE – see how the generic drug names within the same class tend to end
with the same suffix? This is very helpful in learning drugs!
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H2-RECEPTOR ANTAGONISTS
Inhibits interaction of histamine (H2) at the H2-receptors
 Histamine receptors in gastric mucosa mediate the secretion
of gastric acid and pepsin
 Work to directly inhibit the acid secretions
 Not affected by food (ok with or w/o meals)
 best to take at bedtime (acid production peaks during the
overnight hours!)
 Well tolerated, low incidence of side-effects
 Very effective for GERD
 Available as OTC and RX
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PROTON PUMP INHIBITORS (PPIS)
Inhibits chemicals essential to Gastric-acid production (H+
and K+ ions, which generate gastric acid)
 For SHORT TERM treatment of benign gastric ulcers and GERD!
 often used in combo with antibiotics for H. pylori to promote
healing and prevent reoccurrence
 Should only be used for confirmed active ulcers and erosive
esophagitis.
 Side effects are relatively rare (headache, abdominal pain,
diarrhea, nausea, constipation are possible)
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PROTECTANTS
 Carafate
(sucralfate)
Adheres to ulcerated tissue, forming a barrier
 Soothing effect like Antacids
 Does not alter pH
 Take on empty stomach
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 Cytotec (misoprostol)
Protects from irritation of certain medications, like NSAIDS
 Used to prevent ulcers in patients who must take medications that
can cause gastric irritation
 Take on a empty stomach
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ANTIBIOTICS
Commonly used to treat Heliobacter pylori
 Treatment with two antibiotics decreases resistance
 Used in combo with bismuth-salts to prevent bacteria from
attaching stomach wall.
 Antibiotics that are commonly used …

Amoxicillin
 Tetracycline
 Metronidazole (Flagyl)
 Clarithromycin (Biaxin)

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antisecretory agents often used in combo (PrevPak)
See table 25-6 in text on page 503
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ANTISPASMOTICS
These relax GI smooth-muscle tissue, reducing cramping and
spasms (IBS)
 Not as commonly used as the previously mentioned
medications due to more frequent Side-Effects
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Cause problems in glaucoma & urinary retention patients
more Side Effects …
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Visual disturbances
Confusion in demented patients
Changes in heart rhythm
Headache
Insomnia
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VITAMINS, MINERALS, AND
GENERAL NUTRITION
CHAPTER - 20
“YOU ARE WHAT YOU EAT”
oYour body needs a balance of nutrients
for optimum health …
• Water
• Minerals/Vitamins
• Proteins/Carbohydrates
• Fiber
• Essential fatty acids
FOOD & NUTRITION BOARD OF THE
NATIONAL ACADEMY OF SCIENCE
o a DRI is a ‘Dietary Reference Intake’ for
vitamins and minerals:
•EAR (ESTIMATED AVERAGE REQUIREMENT)
•RDA (RECOMMENDED DAILY ALLOWANCE)
•AI (ADEQUATE INTAKE)
•UL (UPPER INTAKE LEVEL)
o Vitamins- ( origin of names - see pg. 46)
Organic materials required in minute amounts/ we can’t
manufacture.
o Minerals- non-organic material, found in the “earth”.
o Essential fatty acids- found in fats, not produced by the body made
up of carbon and hydrogen.
o Antioxidants - inhibit oxidation, reducing tissue damage/aging:
• Vitamin C
• Vitamin E
• Lutien
o Fiber - (see table 15-1 for sources)
A food substance, found only in plants… not digested “roughage”
VITAMINS: CHARACTERISTICS
Organic in nature
 Very small amounts needed daily
 Preformed in the diet or synthesized by intestine
 NECESSARY for body’s normal growth & function
 Store in dark containers in a cool place
 NECESSARY for enzymatic reactions
 Common vitamin-deficiency symptoms include …
- aches/pains
- general, overall ‘poor’ feeling
- tiredness/low energy
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‘FAT SOLUBLE’ VITAMINS
obe careful … these can accumulate!
•Vitamin A
•Vitamin D
•Vitamin E
•Vitamin K
‘WATER SOLUBLE’ VITAMINS
(2) General Groups
1)
Those that release energy from food (thiamine, riboflavin)
2)
Aides to red blood cell formation (folic acid, Vitamin B12)
FOLIC ACID IN PREGNANCY
o extremely important supplement for women!
o Reduces the incidence of neural tube birth defects such
as …
* Spina Bifida
* anenchephaly
* encephalocele
o … essential for DNA formation
o Women of childbearing age should consume 0.4-mg/day
of Folic acid
o Also known as ‘Folate’
MINERALS
o Iron – (oral, injectable)
o Calcium (lactate/glucomate/chloride/carb
onate)
o Phosphorous
o Potassium – (chloride/gluconate)
oFreely found in soil, plants used
for food, and sea food.
oOnly required in trace amounts
oRole in transmission of nerve
impulses
oControl of cardiac rhythm