1. Constipation Myths and Facts Slideshow
2. Hemorrhoids Slideshow: Causes, Symptoms, and Treatment
3. Hemorrhoids Quiz: Test Your Medical IQ of Piles

Medical Author:

John P. Cunha, DO, FACOEP

John P. Cunha, DO, FACOEP

John P. Cunha, DO, is a U.S. board-certified Emergency Medicine Physician. Dr. Cunha's educational background includes a BS in Biology from Rutgers, the State University of New Jersey, and a DO from the Kansas City University of Medicine and Biosciences in Kansas City, MO. He completed residency training in Emergency Medicine at Newark Beth Israel Medical Center in Newark, New Jersey.

View Full Profile

Medical Editor:

Jay W. Marks, MD

Jay W. Marks, MD

Jay W. Marks, MD, is a board-certified internist and gastroenterologist. He graduated from Yale University School of Medicine and trained in internal medicine and gastroenterology at UCLA/Cedars-Sinai Medical Center in Los Angeles.

View Full Profile

In this Article

• What is constipation?
• What causes constipation?
• When should a doctor be consulted for constipation?
• What natural remedies can a person take for constipation?
• What over-the-counter preparations can be used for constipation?
• Bulk-forming laxatives
• Stool softeners (emollient laxatives)
• Lubricant laxatives
• Stimulant laxatives
• Saline laxatives and osmotic laxatives
• Enemas and suppositories
• How is constipation treated in infants and in children?
• How is constipation treated during pregnancy?
• Laxatives for Constipation At A Glance
• Patient Comments: Constipation - Causes
• Find a local Gastroenterologist in your town
• Laxatives For Constipation Index

The active ingredients in saline laxatives are mostly magnesium, sulfate, citrate, and phosphate ions. These ions draw water into the intestines. The additional water softens the stool, increases pressure within the intestines, and increases intestinal contractions resulting in the discharge of softer stool. Fleet Phospho-Soda, milk of magnesia, and magnesium citrate are examples of saline laxatives.

Oral doses of saline laxatives should be taken with one to two glasses of water. The onset of bowel response is usually 1/2 to 3 hours after consuming the laxative. Small doses are sometimes recommended for the treatment of occasional constipation, while larger doses can produce complete evacuation of the intestine. Complete cleansing of the bowel is useful in preparing for colonoscopy, sigmoidoscopy, and barium enema.

The active ingredients in osmotic-type laxatives such as GoLYTELY, GlycoLax, and MiraLax is polyethylene glycol (PEG). These work by holding water in the stool to soften the stool and increasing the number of bowel movements. Osmotic-type laxatives are often used to cleanse the bowel prior to colonoscopies or colon surgery.

Precautions

Since there may be some absorption of the active ingredients from the intestines into the blood circulation, saline laxatives should not be used in certain individuals. Individuals with impaired kidney function should not use laxatives containing magnesium or phosphate salts. Excess accumulation of magnesium and phosphate in the blood of these individuals can lead to toxicity. Those who need to limit their sodium intake, such as those with congestive heart failure, kidney disease, and high blood pressure, should not use laxatives that contain sodium.

Side effects of osmotic-type laxatives include nausea, abdominal cramping, or gas. People who have a history of abdominal surgery or bowel obstruction should consult their doctor before using this medication. Caution is advised when using this drug in the elderly because they may be more sensitive to its side effects, especially diarrhea.