Various Types of Laxatives Used to Treat Constipation


Laxatives are substances which soften stool and increase bowel movements. They are used in the relief and treatment of constipation.

The different types of laxatives used to treat constipation include:

  • Stool softeners – These are also known as Emollients. They are the best type of laxative for use by pregnant women, individuals with hemorrhoids, and those recovering from a surgery. Stool softeners add water to the stool which enables an easy bowel movement. They function directly in the small and large intestines. It takes about 5-7 days to be effective. Examples of stool softeners are Surfak and Colace.
  • Hyperosmotic agents – This is a type of hydrating laxative also known as an osmotic agent. It functions in the colon and takes about 1-3 days to be effective. Hyperosmotic agents concentrate more water within the intestine. A good example of this type of laxative is Lactulose. Lactulose functions by osmosis. It helps retain water in the colon and lowers pH through bacterial fermentation to lactic, formic, and acetic acids. It also increases colonic peristalsis.
  • Relistor (Methylnaltrexon Bromide) – Relistor is used for special cases such as opioid-induced constipation (OIC) patients with advanced illness. Opioids are a class of drugs prescribed to kill the pain. They include substances such as codeine, morphine, oxycodone, etc. Examples of laxatives are Carbon, Lomotil, Oxycoton, Demerol etc. These are used when laxative therapy has not been sufficient for treatment of constipation. Relistor should not be used by pregnant women.
  • Stimulant Laxative – A stimulant laxative provides immediate relief from constipation and therefore should not be used daily. Daily use may cause damage to the colon austral fold. A stimulant laxative acts directly in the colon and takes only a few hours to become effective. Regular usage of stimulant laxatives could result in dehydration and electrolyte imbalances. Examples of stimulant laxatives are castor oil, Senna, and Microlax with an active ingredient of bisacodyl and sennosidesis.
  • Castor oil – Castor oil acts directly on the mucosa in the small intestines. It alters water and electrolyte secretion.
  • Fiber (Bulking Agents) – This is also known as roughage. These are hydrophilic agents which increases water content and bulk to stools, aiding in quick movement of the colon. Fiber acts directly on the small and large intestines and takes about 1-3days to become effective. Examples of dietary fiber supplements are Citrucel and Fibercon. Fruits such as kiwi, prunes, apples, and vegetables such as broccoli, cooked winter squash, and baked potatoes, are used as bulking agents. These sources of fiber are recommended by most doctors because they are natural and slow transit constipation. Make sure stay well-hydrated when using this type of laxative because these fiber sources absorb more water.
  • Saline Agent – This is another type of osmotic agent. Saline agents retain water in the hollow of the intestine, soften stool, and increase intraluminal pressure. A saline agent is not recommended for long-term use. They function at the small and large intestines and takes between 30 minutes and 6 hours to become effective.
  • Lubricant Laxatives – An example of this type of laxative is mineral oil. Mineral oil increases the weight of the stool and decreases colonic absorption of water. They are best for short term use. It is not advisable to take mineral oil with other medications.

Adverse Effects – Overdose of any of the above-mentioned laxatives could lead to minor health issues such as dehydration, hypotension, postural dizziness, tachycardia and syncope, and serious health issues such as ulceration of colonic mucosa, renal failure, diarrhea, hypokalemia, metabolic alkaloids etc.

Precaution – Do not use an overdose of laxatives

  • Always drink plenty of water
  • Use fiber first as regular medication
  • If symptoms persist, please see your doctor.