Day 6 - Living

Trying Prescription Drugs for Irritable Bowel Syndrome

Remember that while there are a number of different prescription medications available for IBS, their effectiveness does vary greatly from one person to another.

What particular drug (if any) will work best for you is something you'll most likely have to determine through trial and error. If the first medication you try doesn't help much, keep in mind that there are other options available.

You should work in partnership with your doctor to determine which medication best fits your needs.

Medications for IBS

Medication Class


Principal indication

Side Effects and Comments


Donnatol (belladonna/phenobarbital) Bentyl (Dicyclomine hydrochloride), Levsin/Levbid (Hyoscyamine sulfate)

Pain and diarrhea

Dry mouth and eyes, urinary retention, tachycardia, drowsiness. Can be mildly constipating.


Immodium, Kaopectate, and Maalox (all Loperamide); Lomotil (diphenoxylate and atropine sulfate), Pepto Bismol (bismuth subsalicylate)

urgency, incontinence

Considerable variation in required dose; can induce constipation, drowsiness and/or dizziness.


Librax (Chlordiazepoxide hydrochloride, Clidinium bromide)

Pain, diarrhea

Blurred vision, drowsiness, can be habit-forming.

Tricyclic antidepressants

amines (e.g., nortriptyline,

Pain, diarrhea, other discomforts

Fewer CNS and anticholinergic side effects and less sedation, orthostatic hypotension & weight gain with secondary amines; start low and work up to target dosage. Constipation can worsen.

(e.g., amitriptyline,

Narcotic Analgesics

Vicodin (Hydrocodone), Percodan and Percocet (Oxycodone), Demerol (Meperidine), Codeine, Morphine.

Pain, diarrhea

Drowsiness, dizziness, constipation, nausea. Can be habit-forming. Possible dangerous interactions with other prescription and over-the-counter drugs, and alcohol.

Newer antidepressants

SSRIs (e.g., fluoxetine, paroxetine)

Can be used for pain
management and constipation in patients who are intolerant
to TCAs

Transient exacerbation of nausea; diarrhea can occur with SSRIs; sleep disruption occurs with some agents

(e.g., buproprion, venlafaxine)

5-HT3 antagonist

Alosetron (LOTRONEX)

Affects multiple symptoms in diarrhea-predominant female patients only, including pain,
urgency, and diarrhea.

May cause severe constipation and ischemic colitis. Effectiveness has not been shown in men. Lotronex was withdrawn from the U.S. market November 2000 then reintroduced under stringent prescribing guidelines.

5-HT4 antagonist

Tegaserod (ZELNORM)

Pain and constipation in constipation- predominant female patients

Approved for short-term use only. Approved for women only. May cause diarrhea, bloating, pain.

Under Investigation


5-HT3 antagonist

Under investigation by Solvay Pharmaceutical for chronic diarrhea


5-HT4 receptor

Under investigation by Janssen Research Foundation for chronic constipation

Continue reading First Year: IBS.

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