Constipation Flashcards
Exclusion from Self-treatment
-marked abdominal pain, flatulence
-N/V/D, fever
-chronic condition precluding laxatives (tetraplegia, inflammatory bowel disease, colostomy)
-blood in stool
-anorexia
-under 2 y
-bowel symptoms for more than 2 weeks or recurring in a period of 3 months
-inflammatory bowel disease
Potential cause of Constipation
-inability to relax the sphincter
-no signal to relax the sphincter
-swollen rectum
Where does stool emptying occur under normal conditions?
-Sigmoid colon
-with medication also emptying of the descending and transversal colon
How is the defecation process initiated?
-Peristaltic movement -> signal to the defecation center in the spinal cord
-sphincter relaxes, abdominal pressure incerases
-voluntary relaxation of the external anal sphincter
Signs of constipation
-frequency of bowel movement has changed
-hard stool
-lassitude, anorexia, low back pain
-abdominal discomfort, distention (Dehnung)
What is the “normal” frequency range of bowel movement?
3x a day to 3x a week
number of BM is not enough to define constipation
-IMPORTANT: know the normal frequency of the patient
Sequelaes of Constipation
-Hemorrhoids
-Cardiovascular problems
-Cardiac rhythm disturbance
-Blood presseure surges
-rectal prolapse
What is the recommended daily intake of fluids and fiber?
-2L of fluid
-14 g per 1000 calories of fiber
Fiber: vegetables, fruits
Fiber vs. Pre-biotic
-Pre-biotic: is the Fiber provided to Pro-biotics
f.e. Fiber supplement with Probiotics
How should a patient increase their amount in fiber intake?
Slowly over a period of weeks, too much fiber may cause other side effects
What is Encopresis?
-often in children -> spots in the underwear
-overstretched rectum -> loss of urge to poo
-first BM is stuck and dries out, the feces behind is liquid and leaks
What is the first line medication to treat constipation?
-Bulk-forming laxative
-FiberCon
MOA Bulk-forming laxatives
-dissolves in the intestinal fluid -> increases bulk in the stool, needs sufficient fluid -> facilitates the passage of intestinal content
-Stimulate peristalsis
What type of patients are appropriate to use FibCon Bulkf-forming laxatives?
-patients who cannot add fiber to the die
-postpartum women (after childbirth)
-older patients
-patients with colostomy (created passage for BM), IBS, diverticular (digestive) disease
Onset of Bulk-forming laxatives
12 to 24 hours ->may take as long as 72 hours
What are the side effects of Bulkf-forming laxatives?
-Abdominal cramping and flatulence
-Esophageal obstruction
-Acute bronchospasm (inhalation of hydrophilic material)
What patient population would not be appropriate to treat with bulk-forming laxatives?
-Heart failure patients are restricted to increased fluid intake to preserve the heart
-children (there are better options)
-DDI: oral tetracyclines - separate by 2 hours
Precautions Bulk-forming laxatives
-Patients at risk for hypercalcemia (HIV, elderly, malignancy, or renal disease -> avoid calcium polycarbophil
-Diabetic patients - some products contain dextrose
-Phenylketonurics - avoid sugar-free agents, bc they contain aspartame
MOA of Emollients
Anionic surfactant -> increases wetting efficiency of intestinal fluid
-> facilitates mixing of aqueous and fatty contents to soften the stool
Onset of Emollients
24 to 72 hours (can take up to 3-5 days)
needs to be taken every day for chronic patients, PRN will not be efficient
When is Emollients appropriate to use?
-For prevention rather than treatment
-prevents painful defecation and straining
-for colostomy patients with constipation
Side Effects and Precautions
-diarrhea and cramping
-Overdoses can cause weakness, sweating, muscle cramps, and irregular heartbeat
Precaution:
-increases the absorption of mineral oil -> toxicity
-Do not use if nausea, vomiting, signs of appendicitis, or undetermined abdominal pain
MOA Lubricant agents
-Mineral Oil
-Oral or rectal
-coating the fecal and preventing the absorption of water in the colon
Onset Lubricant agents
Oral: 6-8 hours
Rectal: 5-15 minutes
Precautions of Lubricant agents
-should be avoided - bc of side effects
-not in children under 6y
-can cause loss of fat-soluble nutrients (Vit A, D, E, K?)
-can be aspirated -> lipid pneumonia
-reduces the absorption of coagulants, contraceptives, and digitalis (treats heart failure)
MOA Saline laxatives
-Non-absorbalbe cations and anions
-draws water into the intestine -> increases intraluminal pressure
-exerts mechanical stimulus
Which patient population is NOT appropriate for Saline laxatives?
-Patients with chronic constipation
-great for relief, not prevention
-pt under 2y
-pt with renal impairment -> frequent intake of magnesium products leads to hypermagnesemia -> hypotension, muscle weakness
Onset of Saline laxatives
Oral: 30 minutes to 3 hours
Rectal: 2-5 minutes (ER room)
-for acute evacuation
DDI of Saline laxatives
-anticoagulants, digitalis, phenothiazines, tetracyclines
Contraindication of Saline laxatives
-patients with ileostomy or colostomy, dehydration
syndromes, renal impairment, and CHF
-patients on sodium restrictions and patients that
cannot tolerate fluid loss
-(Fleet’s Phospho-soda: without adequate hydration -> acute kidney injury when used as a bowel
prep
Hyperosmotic Agents
-Glycerin
-MiraLAX: PEG (Polyethylene glycol) 3350 w/o electrolytes
Glycerin
-Osmotic irritant effects, drawing water into the rectum to stimulate a bowel movement
(Saline laxatives also draw water into the intestine)
Adults can use suppositories, children should use liquids
caution in pt with previous rectal irritation
-Onset: 15 minutes
Onset of PEG 3350
-poorly absorbed ethylene glycol molecules create an osmotic effect
-17 grams mixed in 4-8 ounces of clear liquid
-produce a bowel movement in up to 3 days
Side effects PEG 3350
-bloating, abdominal discomfort, cramping and flatulence
-high doses cause diarrhea
Stimulant laxatives drugs
Anthraquinones and diphenylmethanes
MOA Stimulant
-action on the intramural nerve plexus of the
smooth muscle -> local irritation of the
mucosa
-> increases propulsive peristalsis
Which side effect is especially associated with stimulants?
Crampings throughout the whole large intestine
Why do Anthraquinones mostly work in the colon?
-minimally absorbed -> limited to the colon
-Aloe, casanthranol, senna, rhubarb
-> Only Senna is recommended
Onset and MOA of Anthraquinones
-Onset: 6-12 hours
-Inhibit water and electrolyte absorption from the large intestine
-> Increases intestine volume and pressure to colonic motility
Diphenylmethanes MOA
-Bisacodyl
Tablets: hours; Rectal: Minutes
-contact with the mucosal nerve plexus on the colon
->Producing segmental and axonal contractions of the entire colon
-Onset 15 minutes
Castor oil
-Classified as a stimulant or anionic surfactant (Emollient)
-prolonged use -> excessive loss of fluid, electrolytes, and nutrients
Why can prolonged use of Castor oil cause excessive loss of nutrients?
-Because its site of action is the small intestine (absorption of nutrients)
Side effects of Stimulants
-Severe cramping
-Electrolyte and fluid deficiencies
-Enteric loss of protein
-Malabsorption (excessive hypermotility)
-Hypokalemia
-Colic
-Increased mucous secretions
Council on patients about Stimulative laxatives
-reversible pigmentation of the colonic mucosa
-can change the color of the urine
metabolic acidosis or alkalosis, hypocalcemia, tetany, loss of enteric protein, and malabsorption
Combination of products
-When indicated: senna and docusate
-other combis are NOT recommended unless they are part of colon prep
Which patient population might use combinations of laxatives?
-Patients with chronic diseases
-patients taking opioids
Product selection
First line: bulk-forming laxatives
Second line: PEG 3350
Third line: stimulant (Cations, anions - Mg citrate; Senna)
How to treat patients who seek fast relief?
Lubricant agents: 5-15 min
Saline laxatives (rectal): 2-5 min
Diphenylmethanes (Bisacodyl -rectal): minutes
In the next hours:
Saline Laxatives - Oral: 30 minutes to 3 hours
Lubricant agents - Oral: 6-8 hours
Anthraquinones (Stimulant): 6-12 hours
Laxatives with relief in days
Bulk-forming laxatives: 12-72 hours (up to 3 days)
Emollients: 24-72 hours (1-3 days)
