Choice of laxative therapy for adults

Serra, 2020 Aziz, 2020

Numerous laxatives are available; they are classified by mechanism of action (see Overview of laxatives used in adults). The appropriate laxative for a patient depends on the cause of constipation, the patient’s comorbidities and preference, and the adverse effect profile of the laxative. Identifying the most effective and well-tolerated regimen usually involves trialling different laxatives. Often a combination of laxatives with different mechanisms of action is more beneficial than a large dose of one laxative.

For dosages, see Stepwise approach to laxative therapy for adults.

Table 1. Overview of laxatives used in adults
[NB1]
bulk-forming laxatives
Examples	psyllium ispaghula sterculia
Comments	increase bulk and moisture in the stool, stimulating colonic activity cheap and readily available from supermarkets and health food stores rapidly increasing the dose may result in flatulence and bloating. Ensure adequate fluid intake, or the stool can harden effect is usually apparent within 24 hours, but 2 to 3 days of therapy may be required less effective for nonambulant and chronically constipated patients. Do not use for patients with opioid-induced constipation. Poorly tolerated in patients with functional bloating
osmotic laxatives
Examples	lactulose sorbitol macrogol 3350 magnesium salts
Comments	pull water into, or keep water in, the colon, expanding and softening the stool useful for nonambulant and chronically constipated patients; for chronically constipated patients, regular small doses provide better symptom control than intermittent large doses more rapid effect when taken on an empty stomach; should work within 2 to 48 hours lactulose is not absorbed so may be used short term in patients with diabetes (if other laxatives are ineffective) some osmotic laxatives are not tolerated in irritable bowel syndrome or functional bloating due to bloating and discomfort excessive use may cause fluid and electrolyte disturbance
stimulant laxatives
Examples	senna bisacodyl sodium picosulfate
Comments	stimulate intestinal motility; can cause abdominal cramps useful for nonambulant patients available as single-ingredient preparations, in combination with stool softeners or in herbal preparations effect usually occurs within 6 to 12 hours poorly tolerated in patients with irritable bowel syndrome or functional bloating although there is no evidence to suggest that stimulant laxatives impair the function of the colon, patients who misuse stimulant laxatives may have difficulty resuming a normal bowel pattern when these laxatives are stopped
stool softener
Examples	docusate
Comments	generally available in combination with a stimulant laxative
prokinetic drug
Examples	prucalopride
Comments	5-HT₄ receptor agonist minimal adverse effects stop therapy if no significant effect after a 2-week trial
Note: NB1: For advice about laxatives in pregnant people, see Stepwise approach to laxative therapy for adults.