Laxatives (purgatives, aperients) are foods, compounds, or medication that promote and facilitate bowel evacuation by acting locally to stimulate intestinal peristalsis, to soften bowel contents, or both. Laxatives are generally indicated in constipation (bowel movements that are infrequent and/or hard to pass). With constipation stools are usually hard, dry, small in size, and difficult to eliminate. At least 1 bowel movement/day is essential for health; yet 3 bowel evacuations/week are quite normal.
The causes of constipation can vary:
- Inadequate intake of dietary fiber
- Less fluid intake
- Lack of exercise, sedentary lifestyle
- Changes in life or routine
- Misconception about normal frequency, amount or consistency of stools
- Side effects of medications (narcotics, antispasmodics, antiparkinsonism drugs, antidepressants, diuretics, etc.)
- Diseases like irritable bowel syndrome, hypothyroidism, colorectal cancer, etc.
Laxative or Purgative abuse:
Some individuals are obsessed with using purgatives regularly. Laxative abuse occurs when a person attempts to get rid of unwanted calories, lose weight, feel thin, or feel empty through the repeated misuse of laxatives. This may be the reflection of psychological problem.
Others use a purgative casually, obtain thorough bowel evacuation, and by the time the colon fills up for a proper motion (2-3 days) they get convinced that they are constipated and start taking the drug regularly. Chronic use of purgatives give rise to the risk of laxative dependence, i.e., the inability to do without them. Once the purgative habit forms, it is difficult to break.
Health consequences of laxative/purgative abuse:
- Constipation and laxative dependency
- Flairing of intestinal pathology, rupture of inflamed appendix
- Fluid and electrolyte imbalance, specially hypokalemia
- Steatorrhoea, malabsorption syndrome
- Lazy colon, Irritable bowel syndrome
- Renal failure
- Liver damage
- Protein losing enteropathy
- Spastic colitis
- Severe dehydration
How laxative habituation occurs?
When the sigmoid colon and rectum are filled, the natural defecation reflex empties the large bowel (intestine) up to and including the descending colon.
When laxative is taken:
A large bowel irritant purgative (sennae, phenolpthalein, bisacodyl, picosulfate) clears out the entire colon leading to requirement of a longer period for the next natural defecation to occur. Fearing constipation, the user becomes impatient and again resorts to the laxative, which then produces the desired effect as a result of emptying out the upper colonic segments. Therefore, a “compensatory pause” following cessation of laxative use must not give cause for concern.
Development of laxative abuse cylce:
When the colon empties prematurely, there will be an enteral loss of NaCl, KCl and water. To compensate this depletion of NaCl and water, the body responds with an increased release of aldosterone which stimulates their reabsorption in the kidney. The enteral and renal K+ (potassium) loss add up to a K+ depletion of the body, evidenced by hypokalemia accompanied by a reduction in intestinal peristalsis (bowel atonia). The affected individual infers “constipation,” again partakes of the purgative, and the vicious circle is closed.
No laxatives should be used unless suggested by a healthcare provider. Tapering off laxatives is necessary to prevent problems.