IBS — irritable bowel syndrome

Originally published on September 20, 2020. Last updated on April 5, 2021.

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

Summary

• 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.
  • Anticonstipatives.
• 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.
    • Xifaxan 550mg tablet, 1 po tid x 14 days, #42, no refills.
  • Consider a request for a 30-day trial of a GC-C (guanylate cyclase-C) agonist such as Trulance (plecanatide) for IBS-C prior to the followup visit.
    • Trulance 3mg tablet, 1 po qd x 30 days, #30, no refills.
    • Linzess 290mcg (microgram) capsule, 1 po qd x 30 days, 30 minutes before breakfast, #30, no refills.
    • Trulance dosing for CIC is the same as for IBS-C.
    • Linzess comes in 145mcg and 72mcg capsules for CIC (or for patients needing a smaller dose than 290mcg).
  • Explain that each of these drugs is expensive, and if covered as an insurance benefit, is likely to require prior authorization which one’s gastroenterologist or in-person primary care doctor can give. HealthTap’s support team can start the prior authorization process, but sometimes one’s GI or PCP doctor will need to get involved.

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.

Symptoms:

• 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 U.S.
  • Xifaxan has no generic and usually requires insurance prior-authorization that HealthTap’s support team can initiate, but sometimes the patient’s GI or PCP doctor will need to get involved.
  • IBS-C — neomycin, unofficial dosing of 500mg bid x14d is about $40.00.
• Lubiprostone (NNT ?) — selective C-2 chloride channel activator (Amitiza).
• Guanylate cyclase-C receptor (GC-C) agonists (NNT ?).

• • IBS-C — plecanatide (Trulance) 3mg qd, about $450 per month in the U.S.
  • IBS-C — linaclotide (Linzess) 290mcg qd, about $450 per month in the U.S.
  • Each has no generic and usually requires insurance prior-authorization that HealthTap’s support team can initiate, but sometimes the patient’s GI or PCP doctor will need to get involved.
• 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.
• If wanting to try an expensive, newer treatment such as Xifaxan for IBS-D/M, or Trulance or Linzess for IBS-C, 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. However, a HealthTap doctor can start a trial prescription, and HealthTap’s support team can initiate a prior-authorization and hope the insurer accepts it.