Senna is a laxative substance, which means it improves intestinal transit time, and docusate makes the stool softer and easier to pass. Together the two substances are used to treat constipation, but only when the constipation is short-term and does not relate to any underlying illness. When the constipation lasts for longer than a week with use of senna with docusate, then the treatment should be discontinued and a medical professional should be consulted.
Normally, in a healthy person's body, the intestines expel waste matter out of the body through muscle contractions of the intestinal tube, and conscious control over the time of evacuation. Sometimes, though, a person can experience difficulty in expelling waste, and this situation is termed "constipation." Reasons for constipation include problems as simple as not eating enough fiber, but the problem can also be linked to underlying disease.
Laxatives are a group of substances which promote the movement of waste matter through the intestines. As well as waste matter such as indigestible cellulose from plant foods, feces contain water, which helps keep the feces soft and flexible enough to move through the intestines easily. Medications for constipation containing senna with docusate increase the water content in the feces and also improve the muscular contractions of the intestines which push the feces out. The senna is responsible for the muscular effects, and it also promotes the retention of water inside the intestines. Docusate increases the water content of the feces, and together they promote the easy movement of the waste through the body.
While these effects are often helpful to treat the symptoms of constipation, they do not cure the underlying cause. If the constipation is due to poor diet over a few days, then the condition can resolve itself once the patient begins eating more suitable food. Senna with docusate can only be taken for a week or less at a time, so is therefore only suitable for constipation that is temporary.
Possible side effects of the medicine range from mild issues like diarrhea to serious problems like bleeding from the rectum. For safety's sake, senna with docusate is not recommended for long-term use, especially as the laxative may be masking the symptoms of underlying disease. An overdose can also produce serious problems like intense stomach pain and vomiting. When a person uses senna with docusate, he or she should not use other laxative medicines at the same time, in case the effects produce an overdose, and undesirable side effects occur.