Laxatives are medications that promote bowel movements in patients who suffer from constipation. They are typically used only after changes in diet, exercise and other lifestyle patterns fail to promote regularity.

Physicians may also instruct patients to take laxatives prior to certain medical procedures, such as a colonoscopy, which helps detect the presence of colon cancer.

Bowel movements occur with varying frequency among healthy people. However, factors such as a poor diet, physical inactivity, pregnancy, illness and stress can all interrupt a patient’s ability to have normal bowel movements. Laxatives can promote bowel movements in different ways. Some medications soften stools whereas others trigger rhythmic muscle contractions in the intestines that encourage bowel movements to occur.

There are several different types of laxatives. They include:

• Bulking agents. Add water to stool to increase its bulk and stimulate the natural contractions of the large intestine.
  

  

• Stimulant laxatives. Contain stimulants, such as senna, cascara and bisacodyl, which trigger rhythmic muscle contractions in the intestines.
  
  
• Osmotic agents. Draw water from surrounding tissues into the bowel, which creates a soft stool mass and stretches the walls of the large intestine, thereby stimulating contractions.
  
  
• Stool softeners. Add moisture to the stool and prevent dehydration, which keeps the stool from becoming hard and dry.

Most laxatives are available in over-the-counter formulations. They are delivered either orally or rectally. Some are intended to gradually promote regularity over a period of time whereas others work quickly to trigger bowel movements within hours or even minutes.

Although laxatives can help people restore their bowel movements, these medications can also pose certain risks. Frequent use of laxatives can aggravate or even cause constipation. Patients who use certain laxatives too often may develop lazy bowel syndrome, in which the bowels fail to properly function without the aid of laxatives. Pregnant and breastfeeding women, children and elderly people should use extra caution when taking laxatives, as they may have negative effects. For these reasons, patients should not take laxatives without first consulting their physician.

Laxatives are medications used to relieve constipation by promoting bowel movements. There are many different types of laxatives. Some are intended to gradually promote regularity over a period of time whereas others work quickly to trigger bowel movements within hours or even minutes. Some fiber-rich foods such as bran or fruits with sorbitol (a crystalline alcohol) also have laxative effects.

Physicians may also instruct patients to take laxatives prior to certain medical procedures, such as a colonoscopy, which helps detect the presence of colon cancer.

Bowel movements occur naturally at different frequencies for different people. Some people may have as many as three bowel movements a day whereas others normally have as few as three bowel movements per week. However, several factors can interrupt a patient’s pattern or ability to have normal bowel movements. These include poor diet, physical inactivity, pregnancy, illness and stress.

Physicians usually prefer that patients try other methods of promoting regularity before using medications. These may include eating a fiber-rich diet, drinking plenty of fluids and exercising. However, in some cases laxatives may be the best alternative to treat conditions such as persistent constipation.

In most cases, laxatives are available in over-the-counter formulations. However, some laxatives are available only by prescription. Oral laxatives are available in liquid, wafer, tablet, gum, powder and granule forms. Rectal laxatives – which are usually intended to produce a bowel movement in a short period of time – are available as suppositories and enemas.

Patients who take laxatives are urged to remember that the medications can have negative side effects. For instance, patients who use certain laxatives too often may develop lazy bowel syndrome, in which the bowels fail to properly function without the aid of laxatives. In addition, some people may abuse laxatives, such as patients with bulimia nervosa who use laxatives to help maintain their body weight.

The major types of laxatives can be divided into several categories. Bulking agents, also known as fiber supplements or bulk-forming laxatives, are generally considered to be the safest laxatives available. They work slowly and gently, and are taken with water. Bulking agents are not digested, but instead absorb water in the intestine and then swell to soften stool. The water they add to the stool increases its bulk, which stimulates the natural contractions of the large intestine. Patients take small amounts of the medication initially, then gradually take larger doses until they achieve regularity. A drawback of these laxatives is that they may prevent proper absorption of some medications.

As their name implies, stimulant laxatives contain stimulants, including senna, cascara and bisacodyl, which trigger rhythmic muscle contractions in the intestines. When taken orally, they will usually cause a bowel movement within six to eight hours. In suppository form, they can produce a bowel movement in as little as 15 minutes to an hour. Stimulants are considered to be the harshest laxatives and should only be used every three days under close physician supervision. Some studies have found a link between increased cancer risk and phenolphthalein, an ingredient found in some stimulant laxatives. The U.S. Food and Drug Administration (FDA) has proposed a ban on all over-the-counter products containing phenolphthalein, and most manufacturers of laxatives have either replaced the substance or are planning to remove it from their products.

Osmotic agents draw water from surrounding tissues into the bowel, which creates a soft stool mass and stretches the walls of the large intestine, thereby stimulating contractions. There are three types of osmotics:

• Saline laxatives. Used to rapidly empty the lower intestine and bowel, but are not recommended for long-term constipation or repeated use. They have more limited uses than other laxatives and are usually used to provide rapid relief. For example, they may be used in order to provide a stool sample, and to eliminate foods or drugs rapidly from the body in cases of poisoning or overdose. In smaller doses, they may also be used as antacids.
  
  
• Lactulose laxatives. Have a sugar-like composition and work like saline laxatives. However, they produce results more slowly and are used more often in the long-term treatment of chronic constipation. They are also sometimes used to reduce ammonia levels in the blood. This type of laxative is available by prescription only.
  
  
• Polymer laxatives. These cause water to be retained in stool, softening the stool and increasing the number of bowel movements. Polymer laxatives are used on a short-term basis to treat constipation.

Other common types of laxatives include:

• Stool softeners. Add moisture to the stool and prevent dehydration, which keeps the stool from becoming hard and dry. This effect is achieved by decreasing the surface tension of the stool, which allows more water to penetrate the surface. Physicians often recommend these laxatives following childbirth or surgery. Stool softeners do not actually trigger bowel movements, but instead allow the patient to have a bowel movement without straining.
  
  
• Lubricants. Taken orally or in suppository form, lubricants provide a waterproof coating to the stool that locks moisture into the stool and allows it to move through the intestine more easily.
  
  
• Carbon dioxide-releasing agents. These laxatives are available as suppositories and once inserted form the gas carbon dioxide, which then pushes against the intestinal wall and triggers contractions that move along a stool mass.

• Chloride channel activators. Chloride channels are present in the intestinal epihelial cells and when stimualted, there is an increase in fluid secretion in the small intestine. This, in turn, permits the passage of stool. Chloride channel activators are used in treatment of chronic constipation. Lubiprostone is a selective chloride channel activator and is a newly approved medication for treatment for chronic constipation.

Examples of some of these laxatives include:

In addition, some products combine laxatives. These products may be more likely to cause side effects than single-action laxatives. Combination laxatives include:

• Bulking agent/stimulant
• Bulking agent/stimulant/stool softener
• Osmotic/lubricant
• Stimulant/stool softener

Most often, laxatives are prescribed to treat conditions related to constipation, a condition in which a person is unable to have regular bowel movements or is unable to do so comfortably. Several digestive conditions are related to constipation. For example, inflammatory bowel disease (which includes colitis and Crohn's disease) and encopresis both cause constipation that may be helped by the occasional use of mild laxatives. Research also shows that constipation resulting from the use of certain medications, such as opioid painkillers, may also be relieved by laxative use.

Short-term use of laxatives (except saline laxatives) may also be recommended for relief from constipation during pregnancy and shortly after giving birth and for constipation in patients confined to their beds. A physician may also suggest use of laxatives to clear the colon prior to having certain tests or procedures to examine part of or the entire intestine. Such procedures include a colonoscopy or  lower gastrointestinal (GI) series.

In addition to treating constipation, bulking agents (e.g., bran, psyllium) may be used to treat diarrhea.

Laxatives can also be helpful during periods when it is important to avoid straining during bowel movements, such as following surgery or when a person has certain medical conditions that can be worsened by straining. These include:

• Heart disease
• Hemorrhoids
• Hernia (rupture)
• High blood pressure (hypotension)
• History of stroke

Patients who are candidates for taking laxatives should inform their physician about any previous allergic reactions to laxatives or other substances, including foods, preservatives or dyes. 

Patients who have kidney disease should not use saline laxatives that contain magnesium, potassium or phosphates. Kidney problems can cause these substances to build up in the body. Osmotic agents may cause fluid retention in people with kidney or heart problems. Patients with diabetes are urged to use caution, because laxatives often contain high levels of sugar. Patients with high blood pressure or heart disease are also urged to use caution, as many laxatives contain high levels of sodium.

Swallowing difficulties can also present problems for users of oral laxatives. Difficulty swallowing can cause the lubricant laxative mineral oil to enter the lungs, which may result in pneumonia. Bulking agents can also become lodged in the esophagus of patients who have difficulty swallowing.

Use of laxatives is common among individuals with bulimia nervosa, an eating disorder characterized by a pattern of binge eating followed by harmful purging behaviors, including self-induced vomiting and inappropriate use of laxatives. Therefore, laxative use is not recommended for patients with a history of this disorder.

Patients who are not good candidates for laxative use may benefit from other treatments, such as biofeedback. In fact, recent research indicates that biofeedback may be more effective in alleviating certain types of constipation than laxatives. In addition, researchers are currently studying the benefits of alternative types of medications in treating chronic constipation.

Frequent use of laxatives can aggravate constipation. In some cases, it may actually cause constipation. Patients who use stimulant laxatives too frequently may develop lazy bowel syndrome, in which the bowels no longer function properly without the aid of laxatives. Eventually, laxative use may cause damage to nerve cells and muscles in the colon, preventing it from contracting as it should naturally. Overuse of laxatives can also damage the intestinal tract and cause poor absorption of vitamins and other nutrients.

Minor side effects from laxatives that usually do not usually require medical attention include bloating, cramping, diarrhea, nausea, gas, increased thirst, skin irritation in the rectal area and throat irritation (for those taking oral laxatives).

More serious side effects may require medical attention. Patients should notify their physician if they experience any of the following:

• Breathing difficulties
• Intestinal blockage
• Itchiness or skin rash
• Swallowing difficulties
• Dizziness or lightheadedness
• Confusion
• Irregular heartbeat
• Muscle cramps
• Unusual tiredness or weakness
• Pink, red, violet or brown color in urine

Pregnant and breastfeeding women should not take laxatives without first consulting a physician. Stronger laxatives and chloride channel activators have the potential to harm a pregnant woman or a developing fetus. For example, castor oil, a stimulant laxative, is known to sometimes cause early labor. The lubricant laxative mineral oil can interfere with a woman’s ability to absorb nutrients and vitamins A, D and K, and long-term use has been associated with severe bleeding in newborn infants. Bulking agents and stool softeners may be safe to use during pregnancy.

Laxatives are usually considered safe to use during breastfeeding. However, some ingredients may pass into breast milk, causing diarrhea in infants.

Use of the lubricant laxative mineral oil in older adults can lead to a form of pneumonia resulting from inhaling oil droplets into the lungs. Older adults may also be more vulnerable to side effects associated with stimulant laxatives, including weakness, lack of coordination, and dizziness or lightheadedness.

Older adults who use laxatives in enema or suppository form are at greater risk than younger adults for side effects such as weakness, increased sweating and convulsions.

Preparing questions in advance can help patients to have more meaningful discussions with their physicians regarding their conditions. Patients may wish to ask their doctor the following laxative-related questions:

1. Can you tell me the differences between the major types of laxatives?
   
   
2. Which laxatives are most appropriate for my condition?
   
   
3. Are laxatives safe for me to use given my medical history?
   
   
4. Can laxatives interact with any of the other medications I’m currently taking?
   
   
5. Are there any dietary changes I can make instead of using laxatives?
   
   
6. How long should I use laxatives for?
   
   
7. What are the risks associated with using laxatives for a prolonged period?
   
   
8. When can I expect the laxatives to start working?
   
   
9. What should I do if the laxatives don’t seem to work?
   
   
10. Are there special concerns regarding laxative use among people in my age group?