What is the next best step for a patient with persistent gastrointestinal (GI) symptoms, including abdominal pain, discomfort, bloating, gas, and heartburn, despite a normal esophagogastroduodenoscopy (EGD) and colonoscopy, and partial response to dexlansoprazole (Dexilant) 30 mg daily, after an unsuccessful two-week trial of a non-dairy diet?

From the Guidelines

I strongly recommend proceeding with rifaximin (Xifaxan) 550 mg three times daily for 14 days to address your persistent GI symptoms, particularly the bloating, as it is an efficacious second-line drug for IBS with diarrhoea in secondary care, with a moderate quality of evidence 1. Given that you've already tried dietary modifications, including a non-dairy trial, without significant improvement, and you've had normal endoscopic evaluations ruling out structural causes, rifaximin is an appropriate next step. This antibiotic works primarily in the gut and has minimal systemic absorption, targeting bacterial overgrowth that may be contributing to your symptoms. While continuing your dexlansoprazole 30 mg daily for heartburn management, you should monitor your response to rifaximin during and after the treatment course. Common side effects may include nausea, abdominal discomfort, or headache, but these are typically mild. If rifaximin doesn't provide adequate relief, further evaluation for other functional GI disorders like IBS might be warranted. The redundant colon noted on your colonoscopy is generally considered a normal anatomical variant but can sometimes contribute to symptoms like constipation or bloating in some individuals. Some key points to consider when taking rifaximin include:

• It is specifically licensed for IBS with diarrhoea in the USA, but its use may be considered in other countries based on clinical judgment 1.
• The effect of rifaximin on abdominal pain is limited, so it's essential to monitor your symptoms and adjust your treatment plan as needed 1.
• Rifaximin can be used for retreatment if symptoms recur, with studies showing its efficacy in preventing recurrence and providing durable response 1.

From the FDA Drug Label

The mean fasting gastrin concentrations increased from baseline during treatment with dexlansoprazole 30 mg and 60 mg capsules. Increased gastrin causes enterochromaffin-like cell hyperplasia and increased serum CgA levels.

The patient's ongoing GI symptoms, such as pain, discomfort, bloating, gassiness, and heartburn, despite normal EGD and colonoscopy results, may not be directly related to the use of dexlansoprazole.

• The drug label does not provide information on the management of these specific symptoms.
• The patient has already tried a non-dairy diet and dexlansoprazole with some improvement, but the drug label does not offer guidance on the next steps for managing persistent symptoms.
• The GI specialist's suggestion to try rifaximin for bloating is not supported by the dexlansoprazole drug label 2.

From the Research

Ongoing GI Symptoms

The patient is experiencing ongoing GI symptoms, including pain, discomfort, bloating, gassiness, and heartburn, despite having a normal EGD and colonoscopy. The colonoscopy did note a redundant colon.

Dietary and Lifestyle Modifications

The patient has been modifying their diet and lifestyle according to the GI specialist's recommendations. They have also trialed a non-dairy diet for two weeks, but did not notice significant improvement.

Medication

The patient was previously on dexlansoprazole 60 mg BID, but has been reduced to 30 mg daily, which has helped with their symptoms. The specialist suggested rifaximin for bloating if the non-dairy trial was not helpful, but the patient has not tried this yet.

Rifaximin Efficacy

Studies have shown that rifaximin is effective in treating irritable bowel syndrome with diarrhea (IBS-D) and small intestinal bacterial overgrowth (SIBO) symptoms, including bloating.

• A 2023 study 3 found that rifaximin significantly improved multiple, concurrent IBS-D symptoms, including bloating.
• A 2025 study 4 found that rifaximin-alpha increased lactase activity in patients with IBS without constipation and SIBO, and improved symptoms such as abdominal pain, bloating, and flatulence.
• A 2007 study 5 found that rifaximin was effective in reducing symptoms and normalizing the glucose breath test in patients with SIBO.
• A 2014 study 6 found that herbal therapy was equivalent to rifaximin in treating SIBO, with a similar remission rate.

Rifaximin for Bloating

A 2024 systematic review and meta-analysis 7 found that rifaximin therapy was associated with an increased likelihood of improvement in bloating and distension, as well as a reduction in the subjective severity of these symptoms in patients with functional gastrointestinal disorders (FGID).

• The study found that rifaximin led to a higher likelihood of improvement in symptoms of bloating, with a relative risk of 1.22.
• The study also found that rifaximin led to a greater reduction in bloating scores compared to placebo, with a standardized mean difference of -0.3.

Potential Next Steps

Based on the evidence, rifaximin may be a potential treatment option for the patient's bloating symptoms. However, it is essential to consult with the GI specialist to determine the best course of treatment.