Re: lazy bowel syndrome (from the Merck Manuals):
Osmotic agents (Magnesium) pull large amounts of water into the large intestine, making the stool soft and loose. The excess fluid also stretches the walls of the large intestine, stimulating contractions. These laxatives consist of salts or sugars that are poorly absorbed. They may cause fluid retention in people who have kidney disease or heart failure, especially when given in large or frequent doses.
In general, osmotic laxatives are reasonably safe even when used regularly. However, osmotic agents that contain magnesium and phosphate are partially absorbed into the bloodstream and can be harmful to older people, people who have kidney failure or kidney disease, and people who take drugs that affect kidney function (such as diuretics, angiotensin-converting enzyme [ACE] inhibitors, and angiotensin II receptor blockers).
Stimulant laxatives (such as phenolphthalein, bisacodyl, and anthraquinones) contain irritating substances,
such as senna and cascara. These substances stimulate the walls of the large intestine, causing them to contract and move the stool. They are useful for preventing constipation in people who are taking drugs that will almost certainly cause constipation, such as opioids. Stimulant laxatives are also often used to empty the large intestine before diagnostic tests are done.
Taken by mouth, stimulant laxatives usually cause a semisolid bowel movement in 6 to 8 hours, but they often cause cramping as well. As suppositories, stimulant laxatives often work in 15 to 60 minutes.
Prolonged use of stimulant laxatives can create abnormal deposits of a dark pigment in the lining of the large intestine (a condition called melanosis coli). Other side effects include allergic reactions and loss of electrolytes from the blood. Also, the large intestine can become dependent on stimulant laxatives, leading to lazy bowel syndrome. Therefore, stimulant laxatives should be used only for brief periods.
Something to keep in mind...
