Transcript Document
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
2
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)
2. Increase or decrease ‘emptying time’ (the time it takes food
to pass through the stomach/GI tract) … this is accomplished
by altering ‘peristalsis’
3. Replacement of enzymes (in cases of deficiency)
3
LIFESTYLE MODIFICATIONS FOR GI
PROBLEMS
Foods to avoid
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!)
15
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
Gastric ulcer = Peptic ulcer = stomach ulcer (all the same)
‘Deodenal ulcer’ is found at the junction of stomach and duodenum
5
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
6
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
7
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
8
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)
9
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
10
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
11
ANTISECRETORY AGENTS
These Decrease the secretion of gastric fluids (acid)
Two types
H2-receptor antagonists (H2)
Zantac (ranitidine)
Pepcid (famotidine)
Proton pump inhibitors (PPIs)
Prilosec (omeprazole)
Previcid (lansoprazole)
Nexium (esomeprazole)
* 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!
12
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
13
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)
14
PROTECTANTS
Carafate
(sucralfate)
Adheres to ulcerated tissue, forming a barrier
Soothing effect like Antacids
Does not alter pH
Take on empty stomach
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
15
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)
antisecretory agents often used in combo (PrevPak)
See table 25-6 in text on page 503
16
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
Cause problems in glaucoma & urinary retention patients
more Side Effects …
Visual disturbances
Confusion in demented patients
Changes in heart rhythm
Headache
Insomnia
17
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
‘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