Guest Author - Denise Howard, M.D., M.P.H.

Constipation is a common problem in women. It consists of bowel movements, less than twice weekly and the passage of hard, pellet stools. In many cases it can be relieved by simple dietary measures especially adherence to a fiber rich diet. If this is not affective then medication maybe indicated.

Bulk forming laxatives increases the water content, volume and weight of stool. This improves the stool consistency and transition time through the colon. Psyllium is a natural bulk forming laxative while methylcellulose and polycarbophil are synthetic types. They tend to be more refined and concentrated than bran and of course more expensive. They must be diluted with water or mixed with food.

Osmotic laxatives include sorbitol and lactulose. They are sugars that are not well absorbed. The colonic bacterium tends to break them down into acids. This leads to an accumulation of fluid in the colon resulting in soft formed stools. They can cause bloating and increased gas formation. Miralax or polyethylene glycol is an osmotic agent that is effective and doesn’t cause the bloating or gas formation and is relatively safe for long term use. It is a powder that is mixed with fluid and the dose can be adjusted, usually 8-25 grams a day is needed. Miralax is now available over the counter.

Other laxatives include docusate which can be used short term but is probably not effective for chronic constipation. Mineral oil softens stools and is especially effective for use in enemas. It’s use long term maybe limited by annoying side effects, especially given the availability of more effective laxatives. Saline type laxatives such as magnesium citrate should be used for select circumstances such as when a bowel preparation is required.

Stimulant laxatives typically will work in 2-8 hours. They work by changing fluid and electrolye transport in the colon or by increasing intestinal motility. Their use should be limited to 2-3 times per week as more frequent use can produce electrolyte abnormalities and dehydration. Agents in this group include bisacodyl, senna, and castor oil.

In severe cases enemas made of tap water and mineral oil maybe required to evacuate the rectum. Impaction of stool can occur if constipation is prolonged and in rare instances, colonic perforation can result if the impaction is not relieved. In cases where laxative use is not effective then an evaluation by a specialist, such as a Gastroenterologist or a Colorectal Surgeon maybe needed to prevent this undesired complication of chronic constipation.