How long can I use a laxative for?

If you are like the majority of my patients suffering from constipation, you will self-medicate.  You will find something that helped you once and think that you should always use the same thing over and over day in day out because you had such a “hard time” the last time that you just don’t want to go through that again.

Unfortunately, you can overuse laxatives (and anti-diarrheals’ ) resulting in a pendulum effect between the effects of constipation and diarrhea.

“This type of abuse is present in about 4% of laxative users”

 All drugs currently available for treatment of constipation are generally safe at prescribed doses but further long-term safety data is required. Long-term use of stimulant laxatives has traditionally been discouraged based on tests linking long-term use to damage of the enteric nervous system in the mesenteric plexus and smooth muscles of the colon. However, the results of these tests have not been confirmed by newer technologic methods. Many experts now believe that the risks of long-term stimulant laxative use have been overemphasized, and that they are safe for daily use.l81! However, due to the increased cost and side effects such as cramping, reserve stimulants for third-line therapy when previous treatment has failed.

Melanosis coli is a melanotic hyperpigmentation of the colonic mucosa that occurs after long-term use of the anthraquinones (e.g., senna). It is benign and reverses 3-12 months after discontinuation of the laxative.

Other side effects of laxative overuse include various electrolyte abnormalities; hypermagnesemia, hypernatremia and hyperphosphatemia can occur due to accumulation of absorbed ions derived from the laxative. 

Hypernatremia can also arise when large volumes of osmotic laxatives cause substantial water loss from the GI tract and corresponding fluid intake is insufficient to maintain homeostasis (the tendency toward a relatively stable equilibrium).

Hypokalemia may result as the body tries to regain fluid losses by activating the renin-aldosterone system.

Acute Constipation

Acute and chronic constipation require different management.

Acute constipation lacks a clear definition, the prevalence is unknown and the optimal management has not been well studied. Therapy is often based on your level of discomfort. In general, it is best to clear out hard stool in the distal bowel before using a bulk agent or an aggressive oral regimen.

A reasonable approach is to use an agent with a relatively quick onset of action, e.g., glycerin or bisacodyl suppositories.

As well, saline laxatives may be used to treat acute constipation if there is no indication of bowel obstruction, heart failure or renal impairment. If constipation is not relieved within 48 hours, an agent with a quicker onset of action such as an enema or oral milk of magnesia should be used.

Fecal impaction should be managed by a health-care professional; patients should not attempt to disimpact themselves unless trained to do so. Impaction must be relieved before maintenance treatment can begin; bulk-forming laxatives should be avoided in impacted patients.

Disimpaction may be initiated manually, followed by a phosphate, saline or mineral oil enema (with or without a local anesthetic lubricant) daily for up to 3 days. Tap water or soapsuds enemas should be avoided as they irritate the colonic mucosa and may result in proctitis or colitis. If the stool blockage is higher up in the colon than can be reached with enemas and the patient has no sign of bowel obstruction, oral polyethylene glycol may be used to disimpact the patient (2 L for 1-2 days or 1 L for 3 days).

A single 68 g dose of polyethylene glycol relieved impaction within 19 hours. This is like 4 recommended doses of PEG3550 or brand name Restorolax®. I always keep some in the home- you can mix this white powder in a big glass of water – it tastes almost nothing… and will solve many of your constipation woes….:-)