Pharmacists can play an important role in educating patients about the best options for managing constipation.
Individuals with constipation have fewer than 3 bowel movements per week, and symptoms may include straining during bowel movements, bloating, and hard or lumpy stools.1,2 Additionally, chronic constipation has an estimated prevalence of 15% worldwide and can have a negative impact on daily activities.2 Pharmacists should assess patients for causes of constipation such as certain disease states (eg diabetes) or medications (eg opioids) as part of the management plan.2 Increasing fluids, fitness, and fiber are important lifestyle modifications to start with for treating constipation. However, if these changes do not help, then pharmacists can help patients select an OTC laxative to manage their constipation.
These include fiber supplements (eg psyllium, methylcellulose, calcium polycarbophil) that improve the frequency of bowel movements by retaining water in the stool and increasing stool weight and consistency.1,3 Patients should be educated to drink plenty of water with these products to prevent bloating, cramping, and bowel obstruction.3 Individuals who are immobile, on fluid restriction, or have trouble swallowing should avoid bulk laxatives. These laxatives typically take 12 to 72 hours to work.2
Medications such as bisacodyl work by increasing intestinal motility, and oral products generally take about 6 to 10 hours for onset, with the most common adverse effect (AE) being cramping.1,3 Patients should begin stimulant laxatives at the initiation of opioid therapy to prevent constipation. Oral stimulant laxatives should be avoided in patients with intestinal obstruction.3 Laxative abuse can occur in patients with eating disorders and individuals who continue to use these medications long-term. Symptoms may include severe diarrhea, dehydration, and electrolyte disturbances.3 Therefore, pharmacists should follow up with patients taking stimulant laxatives.
These agents promote secretion of water into the intestinal lumen to soften stools and help stimulate bowel movements.1 Additionally, they usually take 2 to 3 days to produce a bowel movement.2 Osmotic laxatives should be used in patients after surgery or myocardial infarction, since it is important to avoid straining during bowel movements. These agents are another option for managing constipation in patients taking opioids. Osmotic saline laxatives that contain magnesium or sodium should be avoided in patients at risk for electrolyte disturbances (eg heart or renal failure, elderly, taking diuretics).3
Enemas can be used for individuals with fecal impaction, but they should not be used frequently to treat constipation. Glycerin suppositories are a type of osmotic laxative considered safe for use in infants and children for managing constipation that will usually produce a bowel movement in 15 to 60 minutes.3 Parents should be counseled to use only 1 suppository in a 24-hour period. Polyethylene glycol preparations (Miralax; Bayer) are often recommended to treat constipation in children.4 Neuropsychiatric adverse effects have been reported in pediatric patients taking polyethylene glycol.4 One study found that taking the medication daily for 2 weeks did not result in toxic levels of blood glycol.5 However, more studies need to be conducted to determine the long-term effects of polyethylene glycol in the pediatric population and whether it may be associated with safety concerns.5
Pharmacists should educate parents about the possible risk of neuropsychiatric AEs with long-term use of polyethylene glycol products in children.
Medications such as docusate sodium work by moistening the stool by drawing water from the intestines and typically take 24 to 48 hours to work.1 Additionally, these products are often added to stimulant laxatives to treat constipation. Stool softeners are considered safe during pregnancy and can be a good option to help with pregnancy-related constipation.6 Pharmacists can also recommend stool softeners to prevent constipation in pregnant patients taking iron supplements for anemia.
Jennifer Gershman, PharmD, CPh is a drug information pharmacist and medical writer who resides in South Florida.
1. Laxatives. Mayo Clinic. Updated May 1, 2021. Accessed May 7, 2021. https://www.mayoclinic.org/drugs-supplements/laxative-oral-route/description/drg-20070683.
2. Bharucha A, Lacy BE. Mechanisms, evaluation, and management of chronic constipation. Gastroenterology. 2020; 158(5):1232-1249.e3. doi: 10.1053/j.gastro.2019.12.034.
3. Bashir A, Sizar O. Laxatives. StatPearls. Updated September 23, 2020. Accessed May 7, 2021. https://www.ncbi.nlm.nih.gov/books/NBK537246/.
4. Dabaja A, Dabaja A, Abbas M. Polyethylene glycol. StatPearls. Updated October 20, 2020. Accessed May 7, 2021. https://www.ncbi.nlm.nih.gov/books/NBK557652/.
5. Williams KC, Rogers LK, Hill I, Barnard J, Lorenzo CD. PEG 3350 administration is not associated with sustained elevation of glycol levels. J Pediatr. 2018; 195:148-153.e1. doi: 10.1016/j.jpeds.2017.11.028.
6. Tobah YB. Is it safe to take stool softeners to treat pregnancy constipation? Mayo Clinic. Accessed May 7, 2021. https://www.mayoclinic.org/healthy-lifestyle/pregnancy-week-by-week/expert-answers/pregnancy-constipation/faq-20058550.