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Laxatives

Rectal laxatives are used as enemas or suppositories to produce bowel movements in a short time.

There are several different types of rectal laxatives and they work in different ways. The different types of rectal laxatives include:

Carbon dioxide-releasing-Carbon dioxide-releasing laxatives (e.g., potassium bitartrate and sodium bicarbonate) are suppositories that encourage bowel movements by forming carbon dioxide, a gas. This gas pushes against the intestinal wall, causing contractions that move along the stool mass.

Hyperosmotic-Hyperosmotic laxatives (e.g., glycerin; sodium phosphates) draw water into the bowel from surrounding body tissues. This provides a soft stool mass and increased bowel action.

Lubricant-Mineral oil coats the bowel and the stool mass with a waterproof film. This keeps moisture in the stool. The stool remains soft and its passage is made easier.

Stimulants-Stimulant laxatives (e.g., bisacodyl; senna), also known as contact laxatives, act on the intestinal wall. They increase the muscle contractions that move along the stool mass.

Stool softeners (emollients)-Stool softeners (emollient laxatives-e.g., docusate) encourage bowel movements by helping liquids mix into the stool and prevent dry, hard stool masses. This type of laxative has been said not to cause a bowel movement but instead allows the patient to have a bowel movement without straining.

Rectal laxatives are available in the following dosage forms in the US:

Laxative
Rectal solution
(enema)
Suppository
Bisacodyl (Dulcolax, Fleet)
X
X
Docusate (Therevac)
X
 
Glycerin
X
X
Mineral Oil
X
 
Potassium Bitartrate & Sodium Bicarbonate
 
X
Senna
  
X
Sodium Phosphates (Fleet Enema)
X
 
  • Laxative, carbon dioxide-releasing-Potassium Bitartrate and Sodium Bicarbonate
  • Laxative, hyperosmotic-Glycerin
  • Laxative, hyperosmotic, saline-Sodium Phosphates
  • Laxative, lubricant-Mineral Oil
  • Laxative, stimulant (contact)-Bisacodyl; Senna
  • Laxative, stool softener (emollient)-Docusate

Medline Plus Drug Information: Laxatives (Rectal). (Revised: 07/31/1996). Retreived August 23, 2004 from http://www.nlm.nih.gov/medlineplus/druginfo/uspdi/202320.html