What is the cause of chronic diarrhea in a 59-year-old male with diverticulosis and a history of polyp removal, unresponsive to loperamide and probiotics?

From the Guidelines

I strongly recommend continuing Lomotil 2.5 mg (2 tablets by mouth every evening) for 60 days for this 59-year-old male patient with chronic diarrhea while awaiting his GI consultation and upper endoscopy, as it was the only effective treatment for his three-month history of diarrhea that has been unresponsive to loperamide and probiotics 1. The patient's recent colonoscopy showed only minor findings (small rectal polyp, sigmoid diverticulosis, and internal hemorrhoids) that don't explain his persistent diarrhea. The CT scan revealed possible distal esophageal wall thickening that requires further evaluation with an upper endoscopy to rule out esophagitis or neoplasm.

Given the patient's symptoms and lack of response to other treatments, Lomotil is a reasonable choice, as certain antispasmodics may be an effective treatment for global symptoms and abdominal pain in IBS, although dry mouth, visual disturbance, and dizziness are common side effects 1. It's also worth noting that loperamide may be an effective treatment for diarrhea in IBS, but abdominal pain, bloating, nausea, and constipation are common, and may limit tolerability, which was the case in this patient 1.

A 30-day follow-up appointment will allow for monitoring of treatment response and potential side effects before completing the full course. The patient has been appropriately counseled about potential side effects of Lomotil (constipation, blurred vision, urinary hesitancy, dizziness) and the importance of avoiding alcohol while taking this medication. Key considerations for the patient's treatment plan include:

• Monitoring for potential side effects of Lomotil
• Avoiding alcohol while taking Lomotil
• Follow-up appointment in 30 days to assess treatment response and side effects
• Upper endoscopy to rule out esophagitis or neoplasm.

From the Research

Patient's Condition

The patient is a 59-year-old male with a history of diarrhea for over three months. He has tried loperamide and probiotics without improvement. The only medication that has helped is Lomotil 5 mg, which was prescribed for three days.

Diagnostic Findings

The patient underwent a colonoscopy on 04/10/2025, which revealed:

• A 6 mm polyp in the distal rectum, removed with a cold snare
• Diverticulosis in the sigmoid colon
• Internal hemorrhoids
• The examination was otherwise normal A CT Chest/Abdomen/Pelvis with Contrast performed on 2.12.2025 showed:
• No acute traumatic process in the thorax, abdomen, or pelvis
• A small hiatal hernia
• Nonspecific mild wall thickening in the distal esophagus, which may be artifactual or related to esophagitis or paraesophageal neoplasm

Treatment Plan

The patient is scheduled for an upper endoscopy to rule out paraesophageal neoplasm. In the meantime, Lomotil 2.5 mg will be prescribed twice daily for 60 days. The patient will be followed up in 30 days to assess response and side effects.

Relevant Studies

• A study published in 2018 2 found that bismuth subcitrate can improve symptoms and health-related quality of life in adult patients with irritable bowel syndrome (IBS), particularly those with IBS-diarrhea dominant.
• Another study from 2018 3 found that bismuth subsalicylate can reduce the severity and incidence of flatulence and diarrhea in healthy volunteers receiving delayed-release dimethyl fumarate.
• A study from 1978 4 found that codeine phosphate and Lomotil can reduce the loss of water and electrolytes in ileostomy patients, while Isogel can increase the loss of water and electrolytes.
• A systematic review and meta-analysis from 2021 5 found that bismuth subsalicylate can be beneficial for preventing and treating infectious diarrhea, including traveler's diarrhea.
• A study from 2013 6 found that Lomotil (diphenoxylate) can be abused and lead to dependence, highlighting the need for regulatory controls to prevent misuse.

Key Points

• The patient's diarrhea has not responded to loperamide or probiotics, but has improved with Lomotil.
• The patient has undergone a colonoscopy and CT scan, which revealed diverticulosis, internal hemorrhoids, and a small hiatal hernia.
• The patient is scheduled for an upper endoscopy to rule out paraesophageal neoplasm.
• Lomotil will be prescribed for 60 days, with follow-up in 30 days to assess response and side effects.
• Studies suggest that bismuth subcitrate and bismuth subsalicylate can be effective in treating diarrhea and improving symptoms in patients with IBS and infectious diarrhea.