Consult Your Pharmacist - Constipation Has Multiple Causes

W. Steven Pray, Ph.D., R.Ph., Professor of Nonprescription Products and Devices, School of Pharmacy, Southwestern Oklahoma State University, Weatherford, OK

US Pharmacist. 2000;25(6) 

In This Article


Constipation may be treated via manual or pharmacological means. Manual methods are useful for patients with motility problems such as with spina bifida. The patient is instructed to facilitate evacuation by digital manipulation of the anal sphincter.[11]

The safest and most natural of the laxatives are the bulk-forming agents. They replace the fiber that the Western diet tends to lack due to the widespread ingestion of highly refined foods. Bulking ingredients include psyllium, bran, calcium polycarbophil, malt soup extract, and methylcellulose. This month's patient information page discusses adding fiber to one's diet and other methods of preventing constipation.

The emollient laxatives (stool softeners) containing docusate are also a fairly good choice, especially for hard, dry stools. They help maintain an appropriate water-to-fecal mass ratio to allow passage of softer feces.

Generally, the patient should avoid saline laxatives and mineral oil products (unless specifically directed by a physician to use them.) Saline laxatives usually produce watery stools and may dehydrate the patient. Mineral oil can cause aspiration pneumonia and rectal leakage, as well as deficiencies of vitamins A and D.

Phenolphthalein was removed from all major laxative products due to unresolved questions about carcinogenicity. Several other stimulant laxatives are still on the market. However, most of these products (senna, aloe and cascara sagrada) are currently assigned to Category III (more data needed to determine whether they are carcinogenic) by the FDA.[12] Bisacodyl has been cleared of carcinogenicity. (See: "Why Are Some Laxatives Being Reevaluated?")

If a pregnant female asks for a laxative recommendation, the pharmacist should ascertain whether she has discussed the problem with her obstetrician. If not, she should be instructed to do so. The female who has passed her "due date" may have been advised to purchase castor oil by well-meaning friends. This old wives' tale may lead to fatal consequences. Castor oil given to induce labor endangers the fetus (from meconium aspiration) and can cause rupture of the uterus, and death of both mother and child.


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