A Study to Learn More about How Individuals Process Specific Medications Based on Their Genes in Patients with Gastrointestinal Disorders


About this study

The purpose of this study is to:

  1. To evaluate the pharmacogenomic profile (PGx) by genotyping 22 genes, including the CYP2D6 genotype, in patients with functional GI disorders.
  2. To assess the impact of PGx testing on prescriber patterns in this practice.
  3. To explore the impact of PGx testing on patient outcomes after an assessment in this practice.

Participation eligibility

Participant eligibility includes age, gender, type and stage of disease, and previous treatments or health concerns. Guidelines differ from study to study, and identify who can or cannot participate. There is no guarantee that every individual who qualifies and wants to participate in a trial will be enrolled. Contact the study team to discuss study eligibility and potential participation.

Inclusion Criteria

  • Age 18-75 years old.
  • Rome IV criteria for functional nausea and vomiting disorders (chronic nausea vomiting syndrome, cyclic vomiting syndrome), abdominal bloating/distention, dyspepsia, irritable bowel syndrome, chronic abdominal pain, functional diarrhea, or chronic constipation.
  • On 1 or more medications identified in Appendix 1 on a daily basis for at least six months.
  • Symptoms of moderate or severe severity on either of these 2 instruments:
    • For IBS-SSS, use moderate (175-300) or severe (> 300) IBS.
    • For FD – Score ≥ 3 for any symptom on Nepean Dyspepsia Index.
  • No prior pharmacogenomics assessment.
  • Willingness to adjust medications based upon results of PGX testing.
  • Patients must understand and provide written informed consent and HIPAA authorization prior to initiation of any study-specific procedures.
  • Patients must have the ability to complete questionnaires by themselves or with assistance.

Exclusion Criteria:

  • Patients who decline to be evaluated by a mental health professional during their evaluation.
  • Rumination syndrome, cannabinoid hyperemesis syndrome, patients with a significant GI disease process (e.g., intestinal pseudo-obstruction, severe gastroparesis, megacolon) which, in the opinion of the investigator, is likely irreversible.
  • Patients who, in the opinion of the investigator, are likely to undergo another major therapeutic intervention during the next 6 months (e.g., surgery or pelvic floor retraining by biofeedback therapy). However, other changes (e.g., medications) will not preclude participation in the study.
  • Patients with any of the following per history, and review of medical record prior to study entry:
    • Any psychotic disorders, bipolar disorders, or major cognitive disorders;
    • Any active substance use disorders, other than tobacco;
    • Currently active suicidal ideation;
    • Current treatment with electroconvulsive therapy (ECT) or repetitive transcranial magnetic stimulation (rTMS);
    • Discharge from a psychiatric inpatient hospital or intensive psychiatric outpatient program within 6 weeks prior to GI consultation.
  • Patients who are unwilling or cannot, for any reason, adjust their medications.

Participating Mayo Clinic locations

Study statuses change often. Please contact the study team for the most up-to-date information regarding possible participation.

Mayo Clinic Location Status Contact

Rochester, Minn.

Mayo Clinic principal investigator

Adil Bharucha, M.B.B.S., M.D.

Closed for enrollment

Contact information:

Vicki Clark CCRP

(507) 293-7833


More information


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