Study stopped due to lack of volunteer patients.

The aim of this study is to evaluate the effects of Mesalamine and Amitriptyline drugs on the Quality of Life and Symptom Severity Scale in patients with Diarrhea- Predominant Irritable Bowel Syndrome (IBS-D).

All patients will fill three validated questionnaires (IBS Symptom Severity Scale (IBS-SSS) , Hospital Anxiety and Depression Scale (HADS ) and IBS Quality of Life (IBS-QOL) ) at the beginning of trial and at weeks 2,4,6 and 8 of treatment.

Serum Immune Bio markers will be measured at 0,4, and 8 weeks of treatment. This study is a clinical trial upon 90 patients with Diarrhea- Predominant IBS (IBS-D) who are referred for the first time to our private gastrointestinal clinic from 2014 until 2016.

All patients who meet the inclusion criteria enrolled for a 2-week period screening phase. In order to exclude patients with Lactose intolerance, all patients take a lactose-free diet for 14 days before inclusion and patients whose symptoms improve by this regimen will be excluded.

This trial is a double-blind study and all patients will be assigned randomly to three groups:

1. Mesalazine group: Patients receive Asacol (800 mg/TDS) and a placebo agent similar to Amitriptyline (10 mg/HS) for 8 weeks
2. Amitriptyline group: Patients receive Amitriptyline (10 mg/HS) and a placebo like Asacol (800 mg/ TDS) for 8 weeks
3. Control group (placebo group): Patients receive placebo like Asacol (800 mg/TDS) and placebo similar to Amitriptyline (10 mg/HS) for 8 weeks

Ethical considerations:

1. All patients will fulfill an informed consent
2. Drugs are available without any charge
3. Observation of Helsinki ethical statement

Inclusion Criteria:

1. Establishment of diagnosis of IBS by ROME-III criteria
2. Age > 18 years old and < 65 years old
3. Normal colonoscopy or sigmoidoscopy
4. Negative celiac serologic markers
5. Normal complete blood count (CBC) and stool exam and stool culture
6. The patient should not be administered Anti-inflammatory drugs such as Nonsteroidal Antiinflammatory Drugs(NSAIDs), oral or parenteral Antibiotics, Corticosteroids, Mast cell stabilizers, Narcotics, Antidepressants and Immunosuppressive Agents.
7. Normal thyroid-stimulating hormone (TSH )
8. Normal Serum Calcium
9. Educated patient

Exclusion Criteria:

1. Breast feeding and Pregnancy
2. Presence of acute or chronic inflammation which can change the basal level of cytokines
3. Allergic disorders like Asthma (family and personal history)
4. Presence of organic disease like Diabetes mellitus or Psychiatric disorders.
5. Alcohol dependency and addiction to Tobacco and Opium
6. Patients who do not use efficient contraception method
7. History of extensive abdominopelvic surgery except Appendectomy, Cholecystectomy, Hysterectomy and Cesarian-Section
8. Presence of Celiac disease
9. History of Crohn's disease, Ulcerative Colitis and Diverticulitis during the previous year.
10. History of Cardiac, Pulmonary, Hepatic and Renal disease
11. Presence of chronic GI disorders
12. History of Allergy to Aspirin, Mesalamine or Sulpha compounds
13. History of Lymphocytic or Microscopic Colitis
14. History of significant weight loss ( 10% of body weight during 6 months), nocturnal sweating, GI bleeding and family history of Colon cancer
15. Patients with Lactose intolerance disease
16. Presence of Bowel Acid Malabsorption