Chapter 51: bowel disorders Flashcards
• Drugs used to treat diarrhea are called antidiarrheal drugs. Based on the specific mechanism of action, they are divided into different groups:
adsorbents, antimotility drugs, and probiotics (also known as intestinal flora modifiers and bacterial replacement drugs).
• Adsorbents work by coating the wall of the GI tract
. They bind the causative bacteria or toxin to the adsorbent surface in the intestine to be eliminated from the body through stool. They may increase bleeding and cause constipation, dark stools, and black tongue.
. The antilipemic drugs
drugs colestipol and cholestyramine are anion exchange resins prescribed as antidiarrheal adsorbents and lipid-lowering drugs
action of opiates in diarrhea treatment
• The primary action of opiates in diarrhea treatment is to reduce bowel motility. A secondary effect that makes opiates beneficial in the treatment of diarrhea is reduction of the pain associated with diarrhea by relief of rectal spasms.
• Anticholinergic drugs work
to slow peristalsis by reducing the rhythmic contractions and smooth muscle tone of the GI tract; they also have a drying effect and reduce gastric secretions. They are used in combination with adsorbents and opiates. Adverse effects include urinary retention, headache, confusion, dry skin, rash, and blurred vision.
• Probiotics
• Probiotics are also used to manage diarrhea and consist of bacterial cultures of Lactobacillus. They reestablish normal intestinal flora destroyed by infection or antibiotics and suppress the growth of diarrhea-causing bacteria
A number of the antidiarrheals have the potential to alter
• Many drugs are absorbed from the intestines into the bloodstream, where they are delivered to their respective sites of action. A number of the antidiarrheals have the potential to alter this normal process by either increasing or decreasing the absorption of these other drugs
• In 2008, a new class of drugs was approved for the treatment of very specific types of constipation related to opioid use and bowel resection surgery
These peripherally acting opioid antagonists include methylnaltrexone (Relistor) and alvimopan (Entereg). They block the entrance of an opioid drug into the bowel cells, thus allowing the bowels to function normally.
• Some of the common uses of laxatives include
facilitation of bowel movements in patients with inactive colon or anorectal disorders, reduction of ammonia absorption in hepatic encephalopathy (lactulose only), treatment of drug-induced constipation, treatment of constipation associated with pregnancy and/or the postobstetric period, treatment of constipation caused by reduced physical activity or poor dietary habits, removal of toxic substances from the body, facilitation of defecation in megacolon, and preparation for colonic diagnostic procedures or surgery.
the frequency of bowel sounds ranges
• When the frequency of bowel sounds ranges from 6 to 32 per minute, it is important to describe exactly what is heard and the amount of activity in each of the four quadrants. Terms such as high-pitched, low-pitched, gurgling, or tinkling may be used to describe the character of the sounds, whereas activity may be described as hypoactive (fewer than 6 sounds per minute), normoactive (between 6 and 32 sounds per minute), or hyperactive (more than the normal range).
