laxatives

WordNet

1. stimulating evacuation of feces
2. a mild cathartic

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2012/11/22 15:24:25」(JST)

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Laxatives (purgatives, aperients) are foods, compounds or drugs taken to loosen the stool, most often taken to treat constipation. Certain stimulant, lubricant and saline laxatives are used to evacuate the colon for rectal and/or bowel examinations, and may be supplemented by enemas under certain circumstances. Sufficiently high doses of laxatives may cause diarrhea. Laxatives work to increase the movement of feces along the colon.

Some laxatives combine more than one active ingredient. Laxatives may be oral or in suppository form.

Foods

Foods that help with laxation include fruits, especially kiwifruit and prunes, bran products, aloe vera, blackstrap molasses, and nuts (especially almonds and walnuts).

Bulk-producing agents

• Site of action: small and large intestine
• Onset of action: 12–72 hours
• Examples: Bran (insoluble fibre), Gamkaraya, Sterculia[Normacol], psyllium husk (Metamucil (soluble fibre)), methylcellulose (Citrucel), polycarbophil, dietary fibre, apples (soluble fibre), broccoli, prunes (soluble fibre).

A bulk-forming agent is a substance, such as fiber in food, that adds bulk and water to stools so that they can pass more easily through the intestines (lower part of the digestive tract).

Also known as bulking agents or roughage, these include insoluble dietary fibre. Bulk-producing agents cause the stool to be bulkier and to retain more water, as well as forming an emollient gel, making it easier for peristaltic action to move it along. They should be taken with plenty of water. Bulk-producing agents have the gentlest of effects among laxatives and can be taken just for maintaining regular bowel movements.

Stool softeners

• Site of action: Small and large intestine
• Onset of action: 12–72 hours
• Examples: docusate (Colace, Diocto), Gibs-Eze

These enable additional water and fats to be incorporated in the stool, making it easier to move.

Lubricants or emollient

• Site of Action: Colon
• Onset of Action: 6–8 hours

These simply make the stool slippery, so that it slides through the intestine more easily. An example is mineral oil, which also retards colonic absorption of water, softening the stool. Mineral oil may decrease the absorption of fat-soluble vitamins and some minerals.

Hydrating agents (osmotics)

These cause the intestines to hold more water within, softening the stool. There are two principal types, saline and hyperosmotic.

Saline

• Site of Action: Small and large intestine
• Onset of Action: 0.5–6 hours
• Examples: sodium phosphate (and variants), potassium sodium tartrate, magnesium citrate, magnesium hydroxide (Milk of magnesia or Cream of magnesia), magnesium sulfate (which is Epsom salt).

Saline laxatives attract and retain water in the intestinal lumen, increasing intraluminal pressure and thus softening the stool. They also cause the release of cholecystokinin, which stimulates the digestion of fat and protein. Saline laxatives may alter a patient's fluid and electrolyte balance.

Hyperosmotic agents

• Site of Action: Colon
• Onset of Action: 0.5–3 hours
• Examples: Glycerin suppositories, sorbitol, lactulose, and polyethylene glycol (PEG).

Lactulose works by the osmotic effect, which retains water in the colon, lowering the pH through bacterial fermentation to lactic, formic and acetic acid, and increasing colonic peristalsis. Lactulose is also indicated in Portal-systemic encephalopathy. Glycerin suppositories work mostly by hyperosmotic action, but also the sodium stearate in the preparation causes local irritation to the colon.

Solutions of polyethylene glycol and electrolytes (sodium chloride, sodium bicarbonate, potassium chloride, and sometimes sodium sulfate) are used for whole bowel irrigation, a process designed to prepare the bowel for surgery or colonoscopy and to treat certain types of poisoning. Brand names for these solutions include GoLytely, GlycoLax, CoLyte, Miralax, NuLytely, SUPREP, Fortrans and others.

Effectiveness

For adults, a randomized controlled trial found PEG [MiraLax or GlycoLax] 17 grams once per day to be superior to tegaserod at 6 mg twice per day. A randomized controlled trial found greater improvement from 2 sachets (26 grams) of PEG versus 2 sachets (20 grams) of lactulose. 17 grams/day of PEG has been effective and safe in a randomized controlled trial for six months. Another randomized controlled trial found no difference between sorbitol and lactulose.

For children, PEG was found to be more effective than lactulose.

Stimulant or irritant

Stimulant laxatives act on the intestinal mucosa or nerve plexus, altering water and electrolyte secretion. They also stimulate peristaltic action and can be dangerous under certain circumstances. They are the most powerful among laxatives and should be used with care.

Common Stimulant Laxatives

Preparation(s)	Type	Site of Action	Onset of
Cascara (casanthranol)	Anthraquinone	colon	36–8 hours
Buckthorn	Anthraquinone	colon	36–8 hours
Senna extract (senokot)	Anthraquinone	colon	36–8 hours
Aloe vera (aloin)	Anthraquinone	colon	58–10 hours
Phenolphthalein	Triphenylmethane	colon	48 hours
Dulcolax (bisacodyl) (PO)	Triphenylmethane	colon	66–12 hours
Dulcolax (bisacodyl) (suppository)	Triphenylmethane	colon	160 minutes
Microlax	enema	rectum and colon	015–60 minutes
Castor oil	ricinoleic acid	small intestine	22–6 hours

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.

Tegaserod (brand name Zelnorm) was discontinued from marketing in the United States on March 30, 2007. It is still available to physicians for patients in emergency situations that are life-threatening or require hospitalization.

Cisapride (brand name Prepulsid) was voluntarily removed from the U.S. market on July 14, 2000 for the same reason as Tegaserod. Its use in many other countries is discontinued or restricted. It is still available for veterinary use as a compound to treat GI tract problems.

Prucalopride (brand name Resolor) is a current drug which was approved for use in the EU October 15, 2009 and in Canada (brand name Resotran) on December 7, 2011. It has not been approved by the Food and Drug Administration for use in the United States, but it is in development by Shire PLC.

Chloride channel activators

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

Uses

• Bowel preparation
• Chronic constipation
• Chronic immobility

Problems with use

Laxative abuse

Laxative abuse is potentially serious since it can lead to intestinal paralysis,^{[citation needed]} irritable bowel syndrome (IBS), pancreatitis,^{[citation needed]} renal failure, and other problems, even though recovery is possible with proper treatment.

Laxative gut

Physicians warn against the chronic use of stimulant laxatives due to concern that chronic use causes the colonic tissues to get worn out over time and not be able to expel feces due to long term overstimulation.^{[citation needed]} A common finding in patients who have used stimulant laxatives is a brown pigment deposited in the intestinal tissue, known as melanosis coli.^{[citation needed]}

Eating disorders

Laxatives are often used by people with an eating disorder.^{[citation needed]} In cases of bulimia nervosa the patient abuses laxatives to get rid of calories, to purge food in the intestines before it becomes digested and absorbed by the body.^{[citation needed]} This will not work, because laxatives hasten the elimination of undigested remains of food in the large intestine and colon.^{[citation needed]} The large intestine and colon do not digest food. They just collect the undigested remains and hold it and absorb water until it is defaecated. Weight loss may be felt, but this is only temporary due to the fact that the person has expelled much of the fluids from their body.^{[citation needed]} The common question of whether or not chronic diarrhea associated with laxative use can promote some degree of true weight loss remains unknown. In any case, this type of laxative misuse causes water to be lost more rapidly than is healthy, potentially leading to dehydration and electrolyte imbalance. Prolonged usage of laxatives will actually cause constipation. The sensation of bloating can be significant due to excessive water retention, leading to people with eating disorders to increase the dosage of the laxatives, resulting in dependency and further complicating the constipation. Abusing stimulant-type laxatives can lead to permanent impairment of the bowels, and the constipation problem becomes irreversible. In addition, blood can develop in stools, and excessive blood loss can result in anemia. Patients recovering from laxative abuse often have several months of problematic water retention, resulting in temporary weight gain (not noticeable on the exterior), and sometimes "pitting" edema (in which pressing on the skin leaves an indentation).^{[citation needed]}

See also

• ATC code A06
• Cathartic

References

UpToDate Contents

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• 1. 成人における慢性便秘のマネージメント management of chronic constipation in adults
• 2. 高齢者における便秘 constipation in the older adult
• 3. 幼児および小児における慢性機能性便秘および便失禁：治療 chronic functional constipation and fecal incontinence in infants and children treatment
• 4. 虚偽性下痢症：臨床症状、診断およびマネージメント factitious diarrhea clinical manifestations diagnosis and management
• 5. 下痢に伴う酸塩基および電解質の異常 acid base and electrolyte abnormalities with diarrhea

English Journal

• Morbidity and medication in a large population of individuals with Down syndrome compared to the general population.

• Alexander M1, Petri H2, Ding Y3, Wandel C4, Khwaja O5, Foskett N1.
• Developmental medicine and child neurology.Dev Med Child Neurol.2016 Mar;58(3):246-54. doi: 10.1111/dmcn.12868. Epub 2015 Aug 18.
• AIM: The aim of this study was to describe the incidence of morbidities and the prevalence of medical prescriptions in a large Down syndrome population.METHOD: A retrospective cohort study was carried out using the UK Clinical Practice Research Datalink from 1 January 2004 to 31 December 2013. We ma
• PMID 26282180

• Polypharmacy, potentially inappropriate medication and cognitive status in Austrian nursing home residents: results from the OSiA study.

• Alzner R1, Bauer U2, Pitzer S2, Schreier MM2, Osterbrink J2, Iglseder B3.
• Wiener medizinische Wochenschrift (1946).Wien Med Wochenschr.2016 Feb 5. [Epub ahead of print]
• There is little research investigating polypharmacy and potentially inappropriate medications (PIM) in connection with cognitive status in residents of Austrian nursing homes. Our findings result from a cross-sectional survey of 425 residents (315 women, 110 men, mean 83.6 years) from 12 Austrian nu
• PMID 26847440

• The influence of non-steroidal anti-inflammatory drugs on the gut microbiome.

• Rogers MA1, Aronoff DM2.
• Clinical microbiology and infection : the official publication of the European Society of Clinical Microbiology and Infectious Diseases.Clin Microbiol Infect.2016 Feb;22(2):178.e1-9. doi: 10.1016/j.cmi.2015.10.003. Epub 2015 Oct 16.
• The composition of the gut microbiome with the use of non-steroidal anti-inflammatory drugs (NSAIDs) has not been fully characterized. Drug use within the past 30 days was ascertained in 155 adults, and stool specimens were submitted for analysis. Area under the receiver operating characteristic cur
• PMID 26482265

Japanese Journal

• 大腸内視鏡検査の前処置が原因と考えられた高マグネシウム血症の一例

• 日本集中治療医学会雑誌 23(1), 65-66, 2016
• NAID 130005118693

• Bowel Movement Frequency, Laxative Use, and Mortality From Coronary Heart Disease and Stroke Among Japanese Men and Women: The Japan Collaborative Cohort (JACC) Study

• Journal of Epidemiology advpub(0), 2016
• NAID 130005116300

• 分娩前7日間に妊婦が行った陣痛発来への取り組み

• 日本助産学会誌 29(2), 251-261, 2015
• NAID 130005127645

Related Links

• List of Laxatives - Drugs.com

Compare laxatives. View important safety information, ratings, user reviews, popularity and more... ... Drugs.com provides accurate and independent information on more than 24,000 prescription drugs, over-the-counter medicines and ...

• Laxatives - NHS Choices - NHSChoices Home Page

Read about the different types of laxatives available, as well as how to use them and how long to use them for. Also, find out about the possible side effects of laxatives.

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