Laxatives Used In Constipation

Published Date: 02 Nov 2017

Abstract

Introduction

Laxatives are agents that add bulk to intestinal contents by retaining water within the bowel lumen by virtue of their osmotic effects, or that stimulate intestinal secretion or motility thereby increasing the frequency and ease of defecation (Ashafa AOT 2011). Many types of laxatives have been developed, including bulking agents, osmotic agents, stimulants and lubricating agents. The extracts from the roots, bark and dried leaves of buckthorn, senna, cascara, aloe, frangula and rhubarb contain anthraquinone derivatives, and are used as herbal laxative preparations (Kumar ABS 2007). Constipation is defined as a condition of the bowels in which the feces are dry and hard, making evacuation difficult and infrequent which may be idiopathic or may be caused by various identifiable disease processes (Kumar ABS 2007) and often chronic functional gastrointestinal disorder affecting 3-15% of the general population. A number of conditions such as metabolic problems, fiber deficiency, anorectal problems, and drugs can cause constipation, consisting of two subtypes, namely, slow-transit constipation and nonsynergic defecation (Ashafa AOT 2011). Research reveals that 50% of patients define constipation by the symptoms reported most often are infrequent, difficult, or incomplete evacuation or the passage of hard stool or the unproductive urge to defecate. Most clinicians define constipation simply as fewer than 3 bowel movements per week but both the Rome II Functional Gastrointestinal Disorders Coordinating Committee and the American College of Gastroenterology Chronic Constipation (CC) Task Force have published current guidelines for diagnosis and treatment that are more specific. Rome II criteria for CC specify that during the preceding 12 months symptoms must have occurred for at least 12 weeks (LA 2005). Constipation is also common gastrointestinal symptom in diabetic patients but exact pathogenesis of constipation in diabetes is not well understood and seems to be due to autonomic dysfunction with a lack of synchronicity between the gut musculature and the sphincters is thought to be the major contributing factor. The diabetic patients with severe constipation had a totally absent gastrocolic response to feeding, with variable consequences resulting in mild to moderate constipation (Bekele G 1996). In children, between 5% and 28% experience great difficulty with elimination of food waste, accompanied with pain, fear, and avoidance (Alcantara J 2008). Textbooks and clinical practice guidelines from the North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition suggested that hypothyroidism should be considered in the differential diagnosis of constipation (Bennett JWE 2012). Constipation is also a common complaint in older adults and although not a physiologic consequence of normal aging, decreased mobility and other co-morbid medical conditions may contribute to its increased prevalence in older adults (Hsieh 2005). At an International Congress of Gastroenterology in Rome, a working group of experts recommended operational definitions, named the "Rome Criteria," for chronic constipation in adults as two or more of the complications for at least 12 weeks in the preceding 12 months like straining with defecation more than 25% of the time or lumpy or hard stools more than 25% of the time or sensation of incomplete emptying more than 25% of the time or manual maneuvers used to facilitate emptying in more than 25% of defecations and in last fewer than three bowel movements per week (McKay 2012). Physical assessment should begin with observation, auscultation, percussion, and palpation while bowel sounds are assessed to assure active motility and transit to rule out bowel obstruction. (McKay et al. 2012). The majority of cases are attributed to functional disorders without a structural underlying cause that could explain symptoms. Risk factors, such as dietary habits, physical inactivity, socioeconomic level, psychological parameters, medications, age, gender, etc have been implicated in the development of chronic functional constipation. However, the specific etiology of this gastrointestinal disorder has not been elucidated (Peppas 2008). Constipation is more common in women, blacks, persons from lower socioeconomic levels, and persons living in rural areas and northern states (Hsieh 2005). People with neurological disease have a much higher risk of both faecal incontinence and constipation than the general population. There is often a fine line between the two conditions, with any management intended to ameliorate one risking precipitating the other (Coggrave M 2006). Bowel problems occur in 27% to 62% of patients with spinal cord injuries (SCI), most commonly constipation, distention, abdominal pain, rectal bleeding, hemorrhoids, bowel accidents, and autonomic hyperreflexia. The acute abdomen, with a mortality of 9.5%, does not present with rigidity or absent bowel sounds but rather with dull/poorly- localized pain, vomiting, or restlessness, with tenderness, fever, and leukocytosis in up to 50% of patients (E 2012). Dysautonomia-related gastrointestinal symptoms, including sialorrhea, dysphagia, and constipation are common in Parkinson’s disease(PD) and negatively impact on patient’ safety and quality of life, yet may not directly correlate with other parkinsonian motor signs (Evatt ML 2009). Gastrointestinal mucosal abnormalities ranging from edema to ulceration occur in two thirds of patients dying of uremia (JY 1993).

Nowadays, 20 to 30% of people over the age of 60 use laxatives more than once a week (Hara 2008). Constipation can be divided into primary and secondary causes (Hsieh 2005) and primary causes of constipation can be further classified into three groups: normal transit constipation, slow transit constipation, and anorectal dysfunction in which normal transit constipation, also known as functional constipation, is the most common. In patients with functional constipation, stool passes through the colon at a normal rate while slow transit constipation is characterized by prolonged delay in the passage of stool through the colon and patients may complain of abdominal bloating and infrequent bowel movements, causes for slow transit constipation are unclear. Anorectal dysfunction is the inefficient coordination of the pelvic musculature in the evacuation mechanism and patients are more likely to complain of a feeling of incomplete evacuation, a sense of obstruction, or a need for digital manipulation and it may be an acquired behavioral disorder, or the process of defecation may not have been learned in childhood (Hsieh 2005). An important secondary cause of constipation is the use of medications, especially those that affect the central nervous system, nerve conduction, and smooth muscle function. This may include measurement of colonic transit time, anorectal manometry, defecography, or a balloon expulsion test to assess colonic transit and anorectal function (Hsieh 2005). The treatment with classic drugs did not cut, in one hand with the inadequate relief of bloating and other symptoms, and with the lack of efficacy in relieving constipation. So far, half of patients were not satisfied with the effect of laxatives on improving quality of life (Meite 2010).

Laxatives

Foods as laxative

The foods having laxative qualities are prunes, pears, bran cereals or other fiber-rich foods by making stools bulkier, which helps encourage intestinal contractions that allow the individual to have an easier time moving his bowels. While fruit overall may be helpful for preventing and dealing with constipation like dried prunes and prune juice are commonly used as a laxative. Pear juice is usually more effective than whole pears for treating constipation., but some people find canned pears effective as well. An individual may do well to avoid bananas when he is constipated, as they can make constipation worse. Laxatives help the bowels push feces out of the digestive system at a faster rate. They can also soften stools, which make it easier for them to be eliminated from the colon. Any weight loss you see is generally water weight. Columbia University health services explains that taking laxatives causes a reaction that flushes water into the intestine, softens the stool, and then causes a muscle reaction to expel it.

Bulk-producing agents

Bulk forming laxatives like Bran (insoluble fibre), Gamkaraya, Sterculia[Normacol], psyllium husk (Metamucil (soluble fibre)), methylcellulose (Citrucel), polycarbophil, dietary fibre, apples (soluble fibre), broccoli, prunes (soluble fibre) are indigestible, hydrophilic colloids, may be natural or synthetic, act in both the small intestine and colon by forming a bulky gel that distends the colon and increase peristalsis. They should be taken with plenty of water to avoid intestinal obstruction and their action is slow (onset is about12-72 hours) and weak, used for maintaining regular bowel movements. These agents may produce abdominal distension due to digestion of plant fibers by bacteria within the colon and contraindicated in fecal impaction or intestinal obstruction. Bulk-producing agents have the gentlest of effects among laxatives and can be taken just for maintaining regular bowel movements and are generally the preferred laxatives for most ages. Psyllium, one type of bulk-forming laxative, has also been used along with diet to treat high cholesterol. Bulk laxatives are generally available over the counter and come in many forms, including liquid, granule, powder, tablet, delayed-release tablet, chewable tablet, packet, capsule, and wafer forms. Failure to take a bulk-forming laxative with sufficient liquid can lead to a blockage in your intestinal tract.

Lubricants or emollient

Lubricant laxatives coat the entire gastro intestinal tract with a thin waterproof film to make the stool slippery and this waterproof film also coats the stool, helping to retain moisture in the stool. The coated stool remains soft as it passes through the colon. Emulsification of the mineral oil also enhances its ability to soften the stool mass. Mineral oil and certain plant oils make stools easier to pass by lubrication but the prolonged use of oil laxatives may interfere with the absorption of certain vitamins. Mineral oil should not be taken with meals because it may delay emptying of the stomach.

Stimulant or irritants

Stimulant laxatives like aloe, cascara, senna compounds, bisacodyl, and castor oil. Bisacodyl (Dulcolax, Correctol) is available OTC in oral pill form and as a suppository or enema induce bowel movements by increasing the contraction of muscles in the intestines, and are effective when used on a short-term basis. The oral form takes 6 to 10 hours to work. Bisacodyl is commonly used in cleansing the colon for colonoscopies, barium enemas, and intestinal surgeries. Other stimulant laxatives include senna (Ex-Lax, Senokot), cascara sagrada (Nature's Remedy), and casanthranol. These laxatives are converted by the bacteria in the colon into active compounds which then stimulate the contraction of colon muscles. Prolonged, chronic use of these laxatives can cause the lining of the colon to become darker than normal (melanosis coli) due to the accumulation of melanin. Castor oil is a liquid stimulant laxative that works in the small intestine. It causes the accumulation of fluid in the small intestine and promotes evacuation of the bowels and usually used to cleanse the colon for surgery, barium enema, or colonoscopy. They stimulate intestinal motility by direct stimulation of the enteric nervous system or colonic electrolyte and fluid secretion examples are Aloe, senna and cascara which are poorly absorbed from the GIT. The main side effects are abdominal cramps, excess fluid loss and dehydration, blood electrolyte disturbances such as low levels of blood potassium (hypokalemia), and malnutrition with chronic use.

Serotonin agonist

These are motility stimulants that work through activation of 5-HT4 receptors of the enteric nervous system in the gastrointestinal tract. However, some have been discontinued or restricted due to potentially harmful cardiovascular side-effects. They are serotonin 5-HT4 partial agonist act by stimulating 5HT4 receptors on the submucosal plexus of nerves stimulates the peristalsis reflex of the stomach, small intestine, large intestine but not the esophagus and also stimulates chloride secretion from the colon leading to increased stool liquidity when administrated orally, before meals because food decreases its absorption. It is used for Chronic constipation and Irritable bowel syndrome

Chloride channel activators

It causes the intestines to produce a chloride-rich fluid secretion which soften the stool, increases motility, and promotes spontaneous bowel movements and used used in the management of chronic idiopathic constipation and irritable bowel syndrome.

Osmotic laxatives

Osmotic laxatives are soluble non-absorbable compounds like magnesium salts, lactulose and Glycerine suppository with onset of action of 0.5 - 3 hours that enter in the substance of stools, exert osmotic pressure and increase fluid content of stools leading to softening and increased bulk in small intestine and colon result in rapid bowel evacuation. If they are given in large doses, defecation may occur in one to two hours, used to treat acute constipation and bowel evacuation prior to surgical procedures (oral or enema). In addition to its osmotic effect, lactulose also lowers colonic pH thereby stimulating the large bowel). Lactulose is slower in action than magnesium salts.

A solution of polyethylene glycol, sodium sulfate, sodium chloride, sodium bicarbonate and potassium chloride (so that no intravascular fluid or electrolyte shift occur) is used for complete colonic cleansing before gastrointestinal endoscopic procedures and smaller doses may be used for treatment of chronic constipation. It does not cause abdominal distension and cramps like lactulose.

Management of constipation

Dietary and lifestyle modification

The dynamic lifestyle with physical exercise each day and also need to schedule enough time for a bowel movement and must not disregard or postpone the urge when it occurs. Drinking of more fluids i.e. approximately eight glasses of water in a day and set up of a regular to time to use the toilet. A number of yoga poses can relieve gas, bloating and constipation. The foods like fatty or fried foods, alcohol, chocolate, coffee, tea, spicy foods & vinegar and tomatoes & tomato sauces.

High fiber diet

Eating a high-fiber diet has many potential health benefits, and it may also help reduce heart disease and diabetes. Eating a diet with insoluble fiber helps to treat digestive problems such as constipation, diarrhea, hemorrhoids and fecal incontinence. Fiber helps the stool pass regularly and can reduce the risk of coronary artery disease and stroke by 40 to 50 percent as well as reduce the risk of developing type 2 diabetes.

Adequate fluid intake

Water can help prevent and alleviate chronic constipation by facilitating the flow of food though the intestines by lubricating the intestines and the food and the best source of hydration, fruit and vegetable juices, clear soups, and herbal teas are also good sources of fluid.

Regular exercise

Exercise helps constipation by decreasing the time it takes food to move through the large intestine, thus limiting the amount of water absorbed from the stool into your body. In addition, aerobic exercise accelerates your breathing and heart rate which helps to stimulate the natural contraction of intestinal muscles. Intestinal muscles that contract efficiently help move stools out quickly. The study of Meshkinpour et al., (1998) shows that regular physical exercise has long been considered in the management of chronic constipation. Meshkinpour H, Selod S, Movahedi H, Nami N, James N, Wilson A. Effects of regular exercise in management of chronic idiopathic constipation. Dig Dis Sci. 1998; 43(11):2379-83.

Laxative poisoning

A laxative is a medication used to produce bowel movements. Laxative overdose occurs when someone accidentally or intentionally takes more than the normal or recommended amount of this medication. Most laxative overdoses in children are accidental. However, some people abuse laxatives by regularly taking overdoses in an effort to lose weight. Nausea, vomiting, abdominal cramping, diarrhea, are most common. Dehydration and electrolyte problems are more common in children than adults. Mineral oil can cause aspiration pneumonia, a condition where vomited stomach contents are inhaled. Products containing methylcellulose, carboxymethylcellulose, polycarbophil, or psyllium may cause choking or intestinal blockage if they are not taken with plenty of fluids.

Kudo K, Miyazaki C, Kadoya R, Imamura T, Jitsufuchi N, Ikeda N. Laxative poisoning: toxicological analysis of bisacodyl and its metabolite in urine, serum, and stool. J Anal Toxicol. 1998 Jul-Aug;22(4):274-8.

Laxative abuse

Laxative abuse is potentially serious since it can lead to variety of health complications and sometimes causing life-threatening conditions like disturbance of electrolyte and mineral balances of sodium, potassium, magnesium, and phosphorus, necessary for proper functioning of the nerves and muscles, including those of the colon and heart and upsetting this delicate balance can cause improper functioning of these vital organs while severe dehydration may cause tremors, weakness, blurry vision, fainting, kidney damage, and, in extreme cases, death. Laxative dependency occurs when the colon stops reacting to usual doses of laxatives so that larger and larger amounts of laxatives may be needed to produce bowel movements while internal organ damage may result in colon infection, Irritable Bowel Syndrome or liver damage. Individuals who abuse laxatives can generally be categorized as falling into one of four groups. By far the largest group is made up of individuals suffering from an eating disorder such as anorexia or bulimia nervosa. The prevalence of laxative abuse has been reported to range from approximately 10% to 60% of individuals in this group. The second group consists of individuals who are generally middle aged or older who begin using laxatives when constipated but continue to overuse them.

Normal bowel function consists of the absorption of nutrients, electrolytes and water from the gut. Most nutrients are absorbed in the small intestine, while the large bowel absorbs primarily water. There are several types of laxatives available, including stimulant agents, saline and osmotic products, bulking agents and surfactants. The most frequently abused group of laxatives are of the stimulant class. This may be related to the quick action of stimulants, particularly in individuals with eating disorders as they may erroneously believe that they can avoid the absorption of calories via the resulting diarrhoea.

Medical problems associated with laxative abuse include electrolyte and acid/base changes that can involve the renal and cardiovascular systems and may become life threatening. The renin-aldosterone system becomes activated due to the loss of fluid, which leads to oedema and acute weight gain when the laxative is discontinued. This can result in reinforcing further laxative abuse when a patient feels bloated and has gained weight.

Roerig JL, Steffen KJ, Mitchell JE, Zunker C. Laxative abuse: epidemiology, diagnosis and management. Drugs 2010; 70(12):1487-503.