drugs for Constipation

Saline or stimulant cathartics are acceptable (e.g., magnesium citrate, polyethylene glycol-electrolyte solution, bisacodyl).

-These drugs should not be used more than once per week. -Frequent use is likely to produce laxative abuse. For occasional use to cleanse the bowel for endoscopic or radiologic examinations

Lactulose (Chronulac)

-a disaccharide that is not absorbed from the GI tract. It exerts laxative effects by *pulling water into the intestinal lumen * to treat constipation and hepatic encephalopathy. The latter condition usually results from alcoholic liver disease in which ammonia accumulates and causes stupor or coma. Metabolism of dietary protein and intestinal bacteria produce ammonia. *Lactulose decreases production of ammonia in the intestine. The goal of treatment is usually to maintain two to three soft stools daily; effects usually occur within 24 to 48 hours. It is important to use the drug cautiously because it may produce electrolyte imbalances and dehydration.

Lactulose(Chronulac)

-acidifies the stool and traps ammonia and eliminates it with other fecal material. *To prevent absorption of intestinal ammonia in patients with hepatic encephalopathy

Stool softeners (e.g., docusate sodium)

-are the agents of choice For patients in whom straining is potentially harmful or painful such as coronary artery disease (e.g., post-myocardial infarction), hypertension, cerebrovascular disease, anal fissures, or hemorrhoids *Surfactant Laxatives-stool softeners/docusate calcium,potassium,sodium (Colace) *decrease surface tension, allowing water to penetrate into stool *stools become softer & easier to expel *1-3 days, taken daily

Sorbitol

-may be given with activated charcoal to remove toxic substances To accelerate elimination of potentially toxic substances from the GI tract (e.g., orally ingested drugs or toxic compounds) -a monosaccharide that pulls water into the intestinal lumen and has laxative effects -Given with sodium polystyrene sulfonate (Kayexalate), a potassium-removal-resin to treat hyperkalemia,it can prevent constipation and aid expulsion of the potassium-resin complex. However, the combination is not recommended as it may cause colonic intestinal necrosis, which can be fatal.

magnesium citrate, milk of magnesia

-not well absorbed from the intestine *increase osmotic pressure in the intestinal lumen and cause water to be retained. Distention of the bowel leads to increased peristalsis and decreased intestinal transit time for the fecal mass. The resultant *stool is semifluid *used when rapid bowel evacuation is needed. With oral magnesium preparations, effects occur within ½ to 6 hours; with sodium phosphate-containing rectal enemas, effects occur within 15 minutes. - Saline cathartics are generally useful and safe *for short-term treatment of constipation, cleansing the bowel before endoscopic examinations, and treating fecal impaction -not safe for frequent or prolonged usage or for certain patients because they may produce fluid and electrolyte imbalances( with impaired renal function are at risk for hypermagnesemia with magnesium-containing laxatives because some of the magnesium is absorbed systemically) (with congestive heart failure are at risk for fluid retention and edema with sodium-containing cathartics) -Saline cathartics containing phosphate, sodium, magnesium, or potassium salts are usually contraindicated or must be used cautiously in the presence of impaired renal function and in people who follow a sodium-restricted diet for hypertension. Ten percent or more of the magnesium in magnesium salts may be absorbed and cause hypermagnesemia; sodium phosphate and sodium biphosphate may cause hyperphosphatemia, hypernatremia, acidosis, and hypocalcemia; and potassium salts may cause hyperkalemia. Polyethylene glycol-electrolyte solution (e.g., NuLYTELY) is formulated for rapid and effective bowel cleansing without significant changes in water or electrolyte balance. The drug is a non absorbable oral solution that induces diarrhea within 30 to 60 minutes and rapidly evacuates the bowel, usually within 4 hours. It is a prescription drug used for bowel cleansing before GI examination (e.g., colonoscopy) and is contraindicated in patients with GI obstruction, gastric retention, colitis, or bowel perforation. Combination products such as HalfLytely combine polyethylene glycol with a stimulant cathartic, bisacodyl, to evacuate the colon in preparation for a colonoscopy. Polyethylene glycol solution (MiraLAX) is an oral laxative that may be used to treat occasional constipation. Effects may require 2 to 4 days. It is a prescription drug, and people should not take it for longer than 2 weeks. Refrigerating magnesium citrate and polyethylene glycol electrolyte solution before giving increases the palatability and retains potency.

Other Drugs in the Class Stimulant Cathartics

Besides bisacodyl(Dulcolax), other stimulant cathartics are available. In addition to irritant, stimulant effects, *glycerin exerts hyper-osmotic effects in the colon. It usually acts within 30 minutes. Available in the form of rectal suppositories, glycerin is not given orally for laxative effects. Oral stimulant cathartics include CASTOR OIL and SENNA preparations(bedtime dose produces morning bowel movement). *also CASCARASAGRADA

Miscellaneous

Lactulose (Chronulac)

Cathartic

Stimulant Bisacodyl (Dulcolax) Saline Milk of Magnesia

Cathartics

The stimulant cathartics are the strongest and most abused laxative products. Two types of cathartics exist: stimulant and saline. Bisacodyl (Dulcolax), a stimulant cathartic, is the prototype cathartic.

Mineral oil

(*encases & slides out) is the only lubricant laxative used clinically. *It lubricates the fecal mass and slows colonic absorption of water from the fecal mass, but its exact mechanism of action is unknown. Effects usually occur in 6 to 8 hours. Oral mineral oil may cause several adverse effects and is *not recommended for long-term use because body becomes dependent. Mineral oil is probably* most useful as a retention enema to soften hard, dry feces and aid in their removal. Oral use of mineral oil may cause potentially serious adverse effects (decreased absorption of fat-soluble vitamins and some drugs; lipid pneumonia if aspirated into the lungs*danger of aspiration). Thus, mineral oil is not an oral laxative of choice in any condition, although occasional use in the alert patient is unlikely to be harmful. It should not be used regularly. With mineral oil, lipid pneumonia and decreased absorption of vitamins A, D, E, and K can occur. QSEN Safety Alert Lipid pneumonia can be prevented by not giving mineral oil to patients with dysphagia or impaired consciousness. Decreased absorption of fat-soluble vitamins can be prevented by not giving mineral oil with or shortly after meals or for longer than 2 weeks.

Laxatives and Cathartics for Specific Conditions

*are for promoting bowel elimination *bulk forming laxatives *surfactant laxative(stool softener) *saline cathartics *stimulant cathartics *lubricant or emollient laxatives

Bulk-forming laxatives (e.g., Metamucil)

- usually are preferred. - However, because obstruction may occur, these agents should not be given to patients with difficulty in swallowing or adhesions or strictures in the gastrointestinal (GI) tract or to those who are unable or unwilling to drink adequate fluids. -For long-term use of laxatives or cathartics in patients who are debilitated, older, or unable or unwilling to eat an adequate diet *substances not absorbed from theintestines *w/water, the agents swell & become gel-like *physiologic in its action; similar to increased intake of dietary fiber *acts w/in 12-24 hrs or 2-3 days to exert effects

1. psyllium (Metamucil)

-acts within 12 to 24 hours,may take 2-3 days to exert its full effects - is essentially unabsorbed by the body -absorbs excess water while stimulating normal bowel elimination -adds bulk and size to the fecal mass that stimulates peristalsis and defecation. -pulls water into the intestinal lumen. -for: occasional constipation or bowel irregularity,to lower cholesterol when combined with a diet low in cholesterol and saturated fat, diarrhea. -It should be noted that because psyllium(Metamucil), like most laxatives, is not absorbed or metabolized extensively, it can usually be used without difficulty in patients with hepatic impairment. *Use carefully with water: polycarbophil(Fibercom) & Psyllium preps(Metamucil) -bulk forming laxatives used in Diarrhea to decrease fluidicity of stools -may cause abdominal discomfort and bloating Children should obtain adequate fiber from dietary intake. Although psyllium(Metamucil)-containing products are available without pres.

A rectal suppository (e.g., bisacodyl) or an enema (e.g., oil retention or Fleet enema)

-is preferred. -Oral laxatives are contraindicated when fecal impaction is present but may be given after the rectal mass is removed. -After the impaction is relieved, measures should be taken to prevent recurrence. - If dietary and other nonpharmacologic measures are ineffective or contraindicated, use of a bulk-forming agent daily or another laxative once or twice weekly may be necessary For fecal impaction

Bisacodyl(Dulcolax)

-is very poorly absorbed in the small intestine following oral administration or in the large intestine following rectal administration half-life of 16 hours. metabolized in the liver. excreted in the feces, and any systemically absorbed portion of the drug is excreted in the urine. and other stimulant cathartics *act by irritating the GI mucosa and pulling water into the bowel lumen. As a result, feces move through the bowel too rapidly to allow colonic absorption of fecal water, so there is elimination of a watery stool. -for the relief of constipation and as part of bowel preparation before medical examinations and surgery, management of neurogenic bowel dysfunction. not restricted with renal or hepatic impairment. -generally avoided in children younger than 6 years of age for occasional constipation - used short term as rescue therapy or cautiously in children with difficult-to-treat constipation. -as with laxatives, cathartics are often used or overused in older adults. - maintaining adequate fluids, a high-fiber diet, and exercise are much preferred to cathartics. -In critically ill patients, an altered diet regime, change in bowel habits, use of medications known to cause constipation, and decreased activity with bedrest increase the risk of constipations. Often, a bowel management program that includes routine laxative administration is necessary. AE:abdominal pain and cramping, nausea, diarrhea, and weakness. Contraindications: known allergy to the drug,presence of undiagnosed abdominal pain or with intestinal obstruction or fecal impaction precludes its use.

Bisacodyl(Dulcolax)

-should not be taken within an hour after ingesting milk, because milk increases gastric pH and may reduce the resistance of the enteric coating of the tablet, resulting in earlier release of the drug Drugs That Decrease the Effects of Bisacodyl(Dulcolax) • Anticholinergic drugs (e.g., atropine) Slow intestinal motility, increasing constipation • H2 receptor blockers (e.g., ranitidine) Decrease stomach acid, resulting in premature tablet dissolution and gastric irritation • Proton pump inhibitors (e.g., omeprazole) Decrease stomach acid, resulting in premature tablet dissolution and gastric irritation - take on an empty stomach, or at bedtime. Patients should swallow the drug whole. QSEN Safety Alert *People should not use frequently or for longer than 1 week because it may produce serum electrolyte and acid-base imbalances (e.g., hypocalcemia, hypokalemia, metabolic acidosis, or alkalosis).The nurse inserts bisacodyl(Dulcolax) rectal suppositories to the length of the index finger, next to the rectal mucosa. Ther. Effects:Oral formulations produce laxative effects in 6 to 12 hours, and a single bedtime dose of bisacodyl(Dulcolax) usually produces a morning bowel movement. Rectal forms of bisacodyl (Dulcolax) typically produce a bowel movement within 15 minutes to 1 hour. Adverse Effects: nurse monitors for bowel elimination patterns and the presence of diarrhea. In addition, the nurse should monitor for the existence of abdominal pain and cramping, nausea, or weakness. - important to instruct the patient to swallow the tablets without chewing and not to take them within an hour after ingesting milk or gastric antacids or while receiving H2 receptor blocker therapy. This prevents abdominal cramping and vomiting associated with premature tablet dissolution and gastric irritation

Laxatives

Bulk-forming Psyllium preparations (Metamucil) Lubricant laxative Mineral oil Surfactant (stool softener) Docusate Sodium (Colace)

Laxatives

Bulk-forming laxatives are soluble fibers that are largely unabsorbed by the intestine. When water is added, these substances swell and become gel-like. Bulk-forming laxatives are the most physiologic laxatives because their effect is similar to that of increased intake of dietary ber. The bulk-forming laxative psyllium (Metamucil, others) is the prototype laxative.

1. psyllium (Metamucil)

used or over-used in elderly. Nondrug measures to prevent constipation re much preferred to laxatives in such patients. If a laxative is required on a regular basis, a bulk-forming psyllium compound (e.g., Metamucil) is best because it is most physiologic in its action. - analgesics slow GI motility and cause constipation. The reduced mobility and altered bowel regimes that are often found in these patients increase the risk of constipation, so they need a bowel mgmt program -home care nurse may assess usual patterns of bowel elimination, identifying patients at risk for constipation, promoting lifestyle interventions to prevent constipation, obtaining laxatives when indicated, and counseling about rational use -this med or any fiber product may result in severe gas and bloating. In addition, there have been reports of abdominal cramping and esophageal or bowel obstruction -contraindicated undiagnosed abdominal pain. danger- may cause an inflamed organ (appendix) to rupture and spill GI contents into the abd cavity with subsequent peritonitis(life-threatening) Other contras: known allergy to drug and intestinal obstruction and fecal impaction *contraindiations -when Diarrhea is caused by Toxic materials, microorganisms(salmonella, E. Coli, Shigella) -antibiotics may be indicated -if antibiotic associated with Colitis...Stop antibiotic! -enzyme deficiency(pancreatic enzymes) -C.Difficile: continual Diarrhea is treated with metronidazole or Vancomycin for 7-10 days

1. psyllium (Metamucil)

QSEN Safety Alert People who have difficulty swallowing, including those with esophageal stricture or other narrowing or obstruction of the GI tract, should not take psyllium(Metamucil). -no known drug or herbal interactions exist. However, the laxative may reduce or delay the absorption of certain medications, including carbamazepine, digoxin, lithium, tricyclic antidepressants, and warfarin. --should take at least 1 hour before or 2 to 4 hours after taking other medications - potential risk of interfering with nutrient absorption, but clear evidence is not available. - important to take the drug with at least 8 ounces of water or another liquid. With the psyllium-containing preparation Metamucil, there have been reports of obstruction in the GI tract when the compound was taken with insufficient fluid. People should take capsules one at a time. -nurse assesses for relief from constipation within 12 to 72 hours. - assesses for choking or trouble swallowing, severe stomach pain or cramping, nausea or vomiting, rectal bleeding, or constipation lasting longer than 7 days. - take as directed with a full glass of liquid, as soon as it is mixed. Maintaining adequate overall intake of fluids also helps improve bowel regularity. QSEN Safety Alert Psyllium(Metamucil) products may contain sugar, sodium, potassium, or artificial sweeteners-concern to patients who have diabetes, high blood pressure, renal disease, or phenylketonuria- important to teach patients to check the product label if they have these conditions.

docusate sodium(Colace) docusate calcium

Surfactant Laxatives (Stool Softeners) - decrease the surface tension of the fecal mass to allow water to penetrate into the stool. They also act as a detergent to facilitate admixing of fat and water in the stool. As a result, stools are softer and easier to expel. These agents have little, if any, laxative effect. Their main value is to prevent straining while expelling stool. They usually act within 1 to 3 days and should be taken daily.