Diagnosis: Digestive System/Gastrointestinal/Irritable Bowel Syndrome.
Treatment: Pharmacy/Prescription Drugs/Xifaxan.
The health plan denied the requested medication Xifaxan as not medically necessary.
The health plan's determination is upheld.

The patient is a female with a request for Xifaxan. A progress note describes a body mass index (BMI) of 23.8. She complains of loose stools and bloating. The abdomen had mild tympany. The impression was a functional bowel disorder with small intestine bacterial overgrowth overlay. The provider is planning to switch Xifaxan to Flagyl and decrease the Linzess. She has a history of irritable bowel syndrome. A colonoscopy showed mild inflammation in the ascending colonic mucosa but the pathology had no evidence of inflammatory bowel disease. She eats a strict gluten and soy free diet but still has pain, bloating, and diarrhea. She continues to take Linzess for constipation. Dicyclomine has helped with some symptoms. The patient reports 5 to 20 bowel movements per day.
She later reported doing better with the gluten-free diet. Xifaxan helps her diarrhea. Linzess helps her keep consistent bowel movements and helps avoid constipation.
At issue is the medical necessity for the requested medication, Xifaxan.

The health plan's determination of medical necessity is upheld, in whole.

This patient does not have a pure irritable bowel syndrome with diarrhea diagnosis. She is taking Linzess which is used for constipation. She has a mixed diarrhea and constipation component to her irritable bowel syndrome (IBS). Long-term, ongoing use of Xifaxan in patients with a mixed IBS constipation and diarrhea components, and a described overlay of bacterial overgrowth, is not considered medically necessary. The treatment and requirement for Linzess which is used for constipation is not consistent with the patient reported 20 bowel movements per day. Therefore, the requested Xifaxan is not medically necessary in this case. This request is beyond the quantity limit allowed by the plan which is 3 separate fourteen-day treatments in one year.
The proposed treatment is not medically necessary and withholding the treatment, in whole or in part, cannot reasonably be expected to affect the patient's health adversely. The patient is being treated for a presumed bacterial overgrowth overlay. This was never confirmed by objective breath testing. There are no randomized controlled studies or well-designed cohort studies that show an improvement in health outcomes in long-term use of this medication for irritable bowel syndrome with diarrhea. The diagnosis of diarrhea predominance in this case is in question in a patient that is on laxatives including Linzess to treat constipation. Based on daily Linzess medication, this patient has mixed criteria or constipation and not just diarrhea.
Chey described: "The nonsystemic (i.e., low oral bioavailability) antibiotic Rifaximin is indicated in the United States and Canada for the treatment of adults with irritable bowel syndrome (IBS) with diarrhea (IBS-D). The efficacy and safety of 2-week single and repeat courses of Rifaximin have been demonstrated in randomized, placebo-controlled studies of adults with IBS. Rifaximin is widely thought to exert its beneficial clinical effects in IBS-D through manipulation of the gut microbiota. However, current studies indicate that Rifaximin induces only modest effects on the gut microbiota of patients with IBS-D, suggesting that the efficacy of Rifaximin may involve other mechanisms. Indeed, preclinical data reveal a potential role for Rifaximin in the modulation of inflammatory cytokines and intestinal permeability, but these two findings have not yet been examined in the context of clinical studies. The mechanism of action of Rifaximin in IBS is likely multifactorial, and further study is needed."