Table 2: Selected Drug Therapies for Irritable Bowel Syndrome

Table 2:
Selected Drug Therapies for Irritable Bowel Syndrome
Predominant Symptoms	Name	Usual Adult Dosage
Diarrhea-predominant	Opioid µ receptor agonisits
	Ioperamide (Imodium) Iomotil (Diphenoxylate)	2-4 mg up to QID prn 5 mg QID prn
	Smooth muscle relaxants
	dicyclomine (Bentyl) hyoscyamine (Levsin, Nu-Lev, Levbid)	20 mg QID initially, then up to 40 mg QID 0.125 mg SL TID prn or 0.375 mg BID po
	Tricyclic antidepressants
	amitriptyline (Elavil, Endep) desipramine (Norpramin)	10-25 mg BID or 25-50 mg QHS 50 mg TID
	Selective 5-HT₃ receptor antagonist
	alosetron (Lotronex)	1 mg QD x 4 wks, may increase to 1 mg BID x 4 wks*

Constipation-predominant	Bulking agents
	psyllium (Metamucil) polycarbophil (Konsyl Fiber) methocellulose (Citrocel)	20 gm/d, divided, with >250 mL water 1-6 gm/d, divided, with >250 mL water 3-6 gm/d, divided, with >250 mL water
	Osmotic laxatives
	polyethylene glycol (Miralax) lactulose (kristalose, cephulac, chronulac, constulose, duphalac, enulose, R O lactulose) sorbitol (ora-sweet)	1 dose (17 grams in glass of water) qd/bid 15-60 mL/d, divided 120 mL of 25% solution
	5-HT₄ agonists
	tegaserod (Zelnorm)	6 mg BID x 4-12 wks

Pain	Smooth muscle relaxants
	dicyclomine (Bentyl) hyoscamine (Levsin, Nu-Lev, Levbid)	As above As above
	Tricyclic antidepressants
	amitriptyline (Elavil, Endep, Paregoric) desipramine (Desipramine, Norpramin)	As above As above
* Prescribing physicians need to enroll in a special Lotronex Risk Management Program.