A 50-year-old man with end-stage renal disease on hemodialysis presents to the urgent care clinic with 3 days of constipation. He says he feels “totally backed up,” despite using stool softeners and fiber supplements regularly. He denies abdominal pain, nausea, vomiting, hematochezia, melena, or weight loss. Medical history also includes hypertension and type 2 diabetes. He is taking amlodipine, insulin glargine, docusate sodium, and psyllium fiber. On examination, his vital signs are stable, and his abdomen is mildly distended and nontender, with normal bowel sounds. Rectal examination reveals normal tone, and a small amount of soft stool with no impaction or masses. He would like a prescription for something to “get things moving again.”
Which of the following laxative options would be most appropriate and safe for this patient’s chronic constipation given his renal disease?
- Magnesium citrate oral solution
- Polyethylene glycol (PEG) powder
- Sodium phosphate (Fleet) enema
- Magnesium hydroxide
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Correct Answer: b. Polyethylene glycol (PEG) powder
The history and examination of this patient suggested uncomplicated chronic slow-transit constipation. His digital rectal examination was normal, with some soft stool palpated in the rectum, and he appeared well overall. You recommended that he continue fiber supplements with psyllium but that he change the docusate to either PEG, senna, or bisacodyl, depending on whether he would find it more palatable to drink his laxative, take a pill, or use a suppository. You explained that docusate is ineffective for most types of constipation. You cautioned him against using sodium phosphate enemas or magnesium salts, as they can cause electrolyte derangements in patients, like himself, with impaired renal function.
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Tracey Davidoff, MD, FACP, FCUCM, has practiced Urgent Care Medicine for more than 15 years. She is Board Certified in Internal Medicine. Dr. Davidoff is a member of the Board of Directors of the Urgent Care Association and serves as Co-Editor-in-Chief of the College of Urgent Care Medicine’s “Urgent Caring” publication. She is also the Vice President of the Southeast Regional Urgent Care Association and a member of the editorial board of the Journal of Urgent Care Medicine. At EB Medicine, Dr Davidoff is Editor-In-Chief of Evidence-Based Urgent Care, and co-host of the Urgentology podcast.
