September 2, 2020in Virtual Care

Irritable Bowel Syndrome - Evaluation and Treatment

Adapted from AAFP recommendations, FDA Prescribing Information, and other sources.


  • Confirm the diagnosis of IBS
  • Ensure no red flags or a need for more diagnostic evaluation
  • Review/document prior treatments/responses
    • Exercise
    • Stress reduction, acupuncture, other CAM
    • Probiotics
    • Antispasmodics – hyoscyamine (Levsin), dicyclomine (Bentyl)
    • Antidiarrheals
  • Recommend followup with a gastroenterologist for continued symptoms:
    • Consider a request for a 2-week trial of new antibiotic Xifaxan (rifaximin for IBS-D or IBS-M) 
prior to the followup visit
      • Rx: 550mg po tid x 14 days, #42, no refills.
    • Explain Xifaxan is expensive, and if covered as an insurance benefit, it is likely to require prior authorization, which only one’s gastroenterologist or in-person primary care doctor can give

1. Confirm the likelihood that your patient has IBS

  • Patients coming to HTMG may have been previously diagnosed
  • Definition (must meet all 3 criteria):
    • Abdominal discomfort or pain associated with altered bowel habits
    • At least three days per month in the previous three months
    • Absence of organic disease


  • Common symptoms:
    • Abdominal pain (most common symptom)
      • Often feels like a cramping sensation
      • Absence of abdominal pain essentially rules out IBS
    • Diarrhea
    • Constipation
    • Alternating diarrhea and constipation
    • Abdominal pain relieved by defecation
    • Feeling of incomplete evacuation
    • Looser stools at onset of abdominal pain
    • More frequent stools at onset of abdominal pain
    • Patient-reported visible abdominal distension
    • Passing mucus per rectum
  • Other G.I. symptoms:
    • Lump in the throat (globus sensation)
    • Belching or flatulence
    • Acid reflux
    • Dysphagia
    • Early satiety
    • Intermittent dyspepsia
    • Nausea
  • Other Non-G.I. symptoms:
    • Noncardiac chest pain
    • Dysmenorrhea
    • Dyspareunia
    • Urinary urgency or frequency
    • Fibromyalgia symptoms

Red Flags:

  • More evaluation needed - e.g., G.I. referral, colonoscopy, upper endoscopy
  • Consider other diagnoses if:
    • Anemia
    • Rectal bleeding
    • Nocturnal symptoms
    • Weight loss
    • Recent antibiotic use
    • Onset after age 50 years
    • Family history of:
      • Colorectal cancer
      • Inflammatory bowel disease
      • Celiac disease

Differential Diagnosis include conditions such as:

  • Carcinoid tumor
  • Celiac disease
  • Colorectal cancer
  • Diverticular disease
  • Drug use (opiate analgesics, calcium channel blockers, antidepressants)
  • Gastrointestinal infection (e.g., Giardia, Amoeba, HIV, bacterial overgrowth)
  • Hyperthyroidism
  • Hypothyroidism
  • Inflammatory bowel disease (e.g., Crohn disease, ulcerative colitis)
  • Ischemic colitis
  • Lactose intolerance

Lab Tests and Imaging Studies

  • Tests that can be helpful - but are not always recommended in IBS routine evaluation, due to low yield of abnormal results:
    • General nutritional status check
      • Complete blood count
      • Complete chemistry panel
      • Serum iron and ferritin
    • Test for inflammatory bowel disease (IBD)
      • C-reactive protein
      • Fecal calprotectin
    • Test for celiac disease while on a gluten-containing diet
      • Serum total IgA and tissue transglutaminase IgA levels
    • Thyroid tests, if constipation
      • TSH and free T4
    • Stool tests, if diarrhea
      • Clostridium difficile GDH and toxins A/B
      • Fecal culture
      • Fecal leukocytes
      • Ova and parasites
  • Other tests not recommended in IBS routine evaluation:
    • Hydrogen breath test for carbohydrate malabsorption
      • See Gastroenterologist first
    • Hydrogen breath test for SIBO
      • Not recommended due to conflicting evidence on IBS-SIBO association
    • Food allergy tests
      • Not recommended due to lack of evidence of IBS-Food Allergy link
  • Abdominal imaging - not recommended unless medically indicated

2. Select treatment (different patients respond to different modalities)

Treatments that can start from HealthTap virtual care, and follow-up with PCP care:

  • Exercise (NNT 7.4) - vigorous exercise three to five times per week
  • Complementary therapies (NNT 2.5 to 4)
    • Stress reduction, peppermint oil, acupuncture, etc.
  • Probiotics (NNT 4)
    • The most effective dosage, species, or strain are unknown
    • Lactobacillus, Streptococcus, Bifidobacterium are examples
  • Antispasmodics (NNT 3 to 7) - e.g., hyoscyamine (Levsin), dicyclomine (Bentyl)
  • OTC laxatives (NNT ?) - e.g., polyethylene glycol (Miralax)
  • Antidiarrheals (NNT ?) - e.g., loperamide (Imodium)

Treatments usually reserved for in-person PCP or gastroenterologist care:

  • Antidepressants (NNT 4 to 5) - e.g., SSRI's, tricyclics
  • Antibiotics (NNT 11)
    • IBS-D or IBS-M - rifaximin (Xifaxan), 550mg tid x 14d, about $1,900.00 in the US
    • Xifaxan has no generic and requires insurance prior-authorization not available from HealthTap (even though an HTMG doctor may write a Rx for Xifaxan)
    • IBS-C - neomycin, unofficial dosing of 500mg bid x14d is about $40.00
  • Lubiprostone (NNT ?) - selective C-2 chloride channel activator (Amitiza)
  • Alosetron (NNT 7) - (Lotronex has U.S. restrictions) serotonin 5-HT3 receptor antagonist
  • Tegaserod (NNT 17) - (Zelnorm has U.S. restrictions) serotonin 5-HT4 receptor agonist

Treatments NOT recommended for IBS

  • Due to lack of evidence:
    • Fiber (soluble or insoluble)

3. Advise patient on follow-up care

Advise patient to see Primary Care Provider or GI Specialist for evaluation and care of IBS-type symptoms

No “prior authorization” is available from HealthTap, but an HTMG doctor may write a Rx. If wanting to try an expensive, newer treatment such as rifaximin antibiotic, typically the patient’s PCP or GI specialist can check if the patient meets medical criteria for the medication, and go through the prior-authorization process to get insurance coverage.

Robert Kwok

Robert Kwok

Robert Kwok, MD, Director of Health Informatics at HealthTap, is a board-certified physician who practiced medicine for 27 years. He earned his MD and pediatrics credentials at Baylor College of Medicine. Before HealthTap, he practiced clinical pediatrics in Northern California, most recently with Stanford Medicine.