Antidiarrheals

Antidiarrheals

Drugs that are used to treat diarrhea.
Diarrhea
I Definition: Abnormal frequent passage of loose stools or abnormal passage of stools with increased frequency, fluidity, and weight. Or with increased stool water excretion.
A. acute:
1. sudden onset in a previously healthy person
2. lasts from 3 days to 2 weeks
3. self-limiting
4. resolves without sequelae
5. causes
a. bacterial
b. viral
c. drug induced
d. nutritional
e. protozoal
B. chronic
1. lasts for more than 3 weeks
2. associated with recurring passage of diarrheal stools, fever, loss of appetite, nausea, vomiting, weight loss, and chronic weakness
3. causes
a. tumors
b. diabetes
c. Addison’s disease
d. hyperthroidism
e. irritable bowel syndrome (IBS)


Antidiarrheals
I Adsorbents
A. Mechanism of action
1. act by coating the walls of the GI tract.
2. bind the causative bacteria or toxin to their adsorbent surface for elimination from the body through the stool
3. ex: bismuth subsalicylate (pepto-bismol). This agent is in an “aspirin-like” compound.
B. Side effects
1. increased bleeding time (anti-coagulant, not a blood thinner)
2. constipation
3. dark stools
4. confusion
5. twitching
6. hearing loss, tinnitus
7. metallic taste
8. blue gums
C. Interactions
1. adsorbents decrease the absorption of many agents including: digoxin, clindamycin, quinidine, and hypoglycemic agents.
2. adsorbents cause increased bleeding time when given with anticoagulants.
D. Agents
1. activated charcoal
2. aluminum hydroxide
3. attapulgite
4. bismuth subsalicylate
5. cholestyramine
6. kaolin-pectin
7. polycarbonphil
****Do not give bismuth subsalicylate to children younger than 16 or teenagers with chicken pox because of the risk of Reye’s syndrome.

II Anticholinergics
A. Mechanism of action
1. decrease intestinal muscle tone and peristalsis of GI tract
2. result: slowing the movement of fecal matter through the GI tract
3. examples:
a. belladonna alkaloids (Donnatal)
b. atropine
c. hyoscyamine
B. Side effects
1. urinary retention, hesitancy
2. impotence
3. headache, dizziness, confusion, anxiety, drowsiness
4. dry skin, rash, flushing
5. blurred vision, photophobia, increased intraocular pressure
6. hypotension, hypertension, bradycardia, tachycardia
C. Indications
1. antacids can decrease effects of anticholinergic antidiarrheal agents.
D. Agents
1. atropine
2. hyoscyamine
3. hyoscine
*** Anticholinergics should not be administered to patients with a history of glaucoma, BPH, urinary retention, recent bladder surgery, cardiac problems, or myasthenia gravis. It will make them worse.

III Intestinal Flora Modifiers
A. Mechanism of action
1. bacterial cultures of Lactobacillus organisms. Work by:
a. supplying missing bacteria to the GI tract
b. suppressing the growth of diarrhea-causing bacteria
2. example: L. acidophilus (Lactinex) Used after a course of antibiotics.
B. side effects: mild
C. Indications
D. Agents
1. Lactobacillus acidophilus


IV Opiates
A. Mechanism of action
1. decrease bowel motility and relieve rectal spasms
2. decrease transit time through the bowel, allowing more time for water and electrolytes to be absorbed.
3. examples:
a. paregoric
b. opium tincture
c. codeine
d. loperamide (Imodium)
e. diphenoxylate (Lomotil)
f. vicodin/hydrocodone
4. Opiates cause constipation in all of our patients
B. Side effects: (some similarities to antcholinergic)
1. drowsiness, sedation, dizziness, lethargy
2. nausea, vomiting, anorexia, constipation
3. respiratory depression
4. bradycardia, palpitations, hypotension
5. urinary retention
6. flushing, rash, urticaria
7. addiction (not Immodium)
C. Agents
1. opium tincture
2. paregoric
3. codeine
4. diphenoxylate (Lomotil)
5. loperamide (Immodium)
6. morphine


***
Opiates have some similarities to anticholinergic drugs

Contraindicated for pts on anti-coagulants

Any liquid med, do not give with other meds. Changes the pH of the stomach.