OBJECTIVETo develop agents that are specifically effective in controlling the key disturbance of visceral hyperalgesia besides abating of associated multiple symptoms, and evaluate comparative effectiveness for IBS symptom relief for standard regimen (antispasmodic and probiotic) and add-on amitriptyine or riluzole regimens following two weeks administration.

METHODS108 patients with visceral hypersensitivity accompanying IBS, divided into three groups were studied. First group received standard treatment (mebeverine 200 mg twice daily and probiotic 200 mg twice daily). Second group received add-on amitriptyline 25 mg before bedtime, while the third group got add-on riluzole 50 mg twice daily. Overall gastrointestinal symptom rating scale improving symptoms and hospital anxiety depression scale improving associated psychological morbidity were employed as measures at induction and at two-week follow-up period. Individual symptom scores were also examined to define the outcome profiles.

RESULTSRiluzole regimen resulted in significant reduction of overall gastrointestinal symptom rating scale score, not the other two regimens. Pain relief was seen with both riluzole and amitriptyline regimens significantly superior to standard treatment regimen, but riluzole effect appeared specific and independent anxiolytic effect. Amitriptyline caused relief in diarrhea and did not benefit in constipation point to non-specific remedial role in IBS.

CONCLUSIONSRiluzole specifically relieves visceral hypersensitivity and is proved to be superior to current treatments in IBS patients. It appears a lead remedy based on glutamate transporter mechanisms in visceral hypersensititvity.