Yes, there are several prescription medications for diarrhea, and the one your doctor chooses depends on what’s causing it. Over-the-counter options like loperamide (Imodium) work well for short bouts, but when diarrhea is chronic, severe, or tied to a specific condition, a prescription can offer stronger or more targeted relief.
When Diarrhea Moves Beyond OTC Treatment
Most cases of acute diarrhea resolve on their own or respond to over-the-counter loperamide within a few days. Doctors typically start considering prescription options when diarrhea lasts longer than four weeks, which is the standard threshold for classifying it as chronic. They may also prescribe something sooner if symptoms are severe, if there’s a known underlying condition, or if OTC medications aren’t providing enough control.
Interestingly, loperamide itself straddles the line between OTC and prescription. The maximum approved daily dose for over-the-counter use is 8 mg per day, but a doctor can prescribe up to 16 mg per day for more stubborn cases. So even a familiar drug can become a “prescription for diarrhea” when a higher dose is needed.
Prescription Options for General Diarrhea
Diphenoxylate is one of the most commonly prescribed antidiarrheal medications. It works similarly to loperamide by slowing down gut contractions, but it’s only available by prescription and is combined with a small amount of atropine to discourage misuse. Difenoxin, a related compound, is also prescription-only and used for acute nonspecific diarrhea or flare-ups of chronic functional diarrhea.
These medications are meant for short-term symptom control. They reduce the frequency and urgency of bowel movements but don’t treat whatever is causing the diarrhea in the first place. Your doctor will likely want to figure out the underlying cause if your symptoms keep returning.
Antibiotics for Infectious Diarrhea
When diarrhea is caused by a bacterial infection, the prescription shifts to an antibiotic. Rifaximin is FDA-approved specifically for traveler’s diarrhea caused by noninvasive strains of E. coli. It’s typically taken three times a day for three days and is approved for anyone 12 years or older. Because rifaximin stays mostly in the gut rather than being absorbed into the bloodstream, it tends to cause fewer body-wide side effects than other antibiotics.
Other antibiotics may be prescribed for different bacterial or parasitic infections depending on what stool testing reveals. The key distinction here is that these prescriptions treat the infection itself, not just the symptom of diarrhea.
Prescriptions for IBS With Diarrhea
Irritable bowel syndrome with diarrhea (IBS-D) has its own set of prescription treatments, because the problem isn’t an infection or inflammation. It’s a disorder of gut-brain signaling.
Eluxadoline (Viberzi) is approved specifically for IBS-D. It works on opioid receptors in the gut to reduce contractions and fluid secretion without the sedating effects of systemic painkillers. In clinical trials, patients qualified for treatment when they had an average worst abdominal pain score above 3 on a 10-point scale and consistently loose stools (averaging 5.5 or higher on the 7-point Bristol Stool Scale) over the prior week.
Alosetron (Lotronex) is another option, but it’s restricted to women with severe IBS-D who haven’t responded to other treatments. It’s sold under a special FDA safety program because of rare but serious risks, including reduced blood flow to the colon and severe constipation. Doctors must enroll in the program before they can prescribe it.
Treating the Cause: Bile Acid and Microscopic Colitis
Some chronic diarrhea has a very specific, treatable cause that standard antidiarrheals won’t fix. Two common examples are bile acid malabsorption and microscopic colitis.
Bile acid malabsorption happens when your body produces too much bile acid or fails to reabsorb it properly in the small intestine. The excess bile irritates the colon and triggers watery diarrhea, often right after meals. Cholestyramine, a prescription powder mixed into liquid, works by binding to bile acids in the intestine so they pass out of the body instead of irritating the colon. It’s not absorbed into the bloodstream, so it acts entirely within the gut.
Microscopic colitis is a type of inflammation visible only under a microscope, not during a standard colonoscopy. It causes persistent watery diarrhea, sometimes for months. The first-line prescription treatment is budesonide, a steroid that targets inflammation locally in the gut. The typical course is 9 mg per day for eight weeks. If symptoms return after stopping, doctors often restart it at a lower dose for six to twelve months.
Condition-Specific Prescriptions
A few prescription antidiarrheals are designed for very narrow situations. Crofelemer is approved specifically for diarrhea caused by antiretroviral medications in people living with HIV/AIDS. It reduces fluid secretion in the intestinal lining without interfering with the HIV treatment itself. Telotristat ethyl (Xermelo) treats diarrhea caused by carcinoid syndrome, a rare condition where tumors release excess serotonin into the bloodstream. It works by blocking the enzyme that produces serotonin in the gut.
These aren’t drugs a general practitioner would typically prescribe for everyday diarrhea. They exist because certain medical conditions cause diarrhea through mechanisms that standard antidiarrheals can’t address.
What Your Doctor Will Want to Know
If you’re considering asking for a prescription, expect your doctor to ask how long the diarrhea has lasted, how many times a day you’re going, whether you see blood or mucus, and whether you’ve lost weight. They’ll want to know if OTC loperamide helped at all and whether your symptoms seem tied to meals, stress, travel, or a new medication.
For diarrhea lasting more than four weeks, basic blood work and stool tests are standard. These help rule out infections, inflammation, and conditions like celiac disease. The results guide which prescription makes sense. A bile acid binder won’t help an infection, and an antibiotic won’t fix IBS. Getting the right prescription starts with getting the right diagnosis.