OTC and Prescription Medications for Diarrhea

Diarrhea is an unpleasant and inconvenient condition. Fortunately, it usually resolves on its own without medication.

When symptoms arise, many people turn to over-the-counter (OTC) medications for relief. OTC medications that you can purchase at a drugstore include Imodium (loperamide), Kaopectate (bismuth subsalicylate), and Pepto-Bismol (bismuth subsalicylate).

These can be helpful for occasional diarrhea. However, in some cases, OTC medications aren’t effective or appropriate for treating diarrhea, particularly if it occurs due to an underlying medical concern. In these cases, prescription medications may be helpful.

Read on for an overview of common OTC medications and prescription drugs available to help diarrhea.

OTC Medicines for Diarrhea

OTC medications are an option for treating occasional episodes of diarrhea. Many different brands and generic products are available without a prescription, but most contain either loperamide or bismuth subsalicylate as a main ingredient.

Imodium (Loperamide)

Imodium A-D is a popular antidiarrheal medicine that contains the active ingredient loperamide.

Imodium is available without a prescripton in several oral forms, including tablets, capsules, and liquids. Loperamide also comes as an OTC combination product called Imodium Multi-Symptom Relief. It contains simethicone as an added active ingredient, which helps to relieve gas.

The table below summarizes the recommended dosages of OTC Imodium A-D products. Note that loperamide 2 milligram (mg) capsules are also available with a prescription. Your healthcare provider may recommend a different dosage than what's shown below.

Loperamide can be safe and effective for controlling diarrhea, such as traveler's diarrhea, in most individuals. However, you should consult with a healthcare professional before giving Imodium to a child under the age of 6.

Also, consult with a healthcare provider before taking loperamide if you have the following symptoms or factors:

• Fever 
• Stool that is bloody or tar-like
• Mucus in the stool
• Swelling or bulging of your abdomen
• Diarrhea that continues for more than two days
• Taking medication conditions, including liver disease or a history of abnormal heart rhythm
• Are pregnant or breastfeeding
• Past allergic reaction to loperamide

While uncommon, side effects may occur when taking loperamide. Potential side effects include drowsiness, dizziness, or tiredness.

Pepto-Bismol (Bismuth Subsalicylate)

Bismuth subsalicylate is another OTC medication available for managing short-term diarrhea. It is commonly known by the brand name Pepto-Bismol. This brand includes a line of products that come in different forms.

Unlike loperamide, which is solely an anti-diarrheal medication, bismuth subsalicylate also treats other symptoms, including upset stomach, heartburn, nausea, and indigestion.

Not all Pepto-Bismol products are identical, so it is important to read the labels carefully. The chart below shows the recommended dosage for two common Pepto-Bismol products.

Bismuth subsalicylate is similar to aspirin and may not be safe for certain people. Check with a healthcare professional before taking bismuth subsalicylate if you have any of the following symptoms or factors:

• Bloody or tar-like stool or mucus in the stool
• Fever
• Diarrhea that gets worse or continues for more than two days
• Stomach or intestinal ulcer
• Bleeding problems
• Taking anticoagulant (blood thinner) medications
• Diabetes
• Gout
• Arthritis
• Past allergic reaction to aspirin or other salicylates

Pepto-Bismol isn’t recommended for children younger than 12. Due to the risk of Reye’s syndrome, it is important not to give bismuth subsalicylate to children or adolescents who have chicken pox, are recovering from chicken pox, or have flu-like symptoms. 

Side effects are rare with bismuth subsalicylate, but may include hearing problems or tinnitus (ringing in the ears). A temporary darkening of bowel movements or the tongue can also occur, but this is harmless and goes away after stopping the medication.

Kaopectate (Bismuth Subsalicylate)

Kaopectate is another OTC option for managing diarrhea in adults and children ages 12 and older.

Like Pepto-Bismol, the active ingredient is bismuth subsalicylate, and carries all the same risks and precautions as described above.

Kaopectate comes in chewable tablets and as an oral liquid. Some people prefer the flavor of Kaopectate to the flavor of Pepto-Bismol.

Prescription Medicines for Diarrhea

Prescription medications may be beneficial for treating chronic or frequent diarrhea caused by medical conditions like irritable bowel syndrome with diarrhea (IBS-D), also known as diarrhea-predominant IBS.

Symptoms of IBS-D may include:

• Frequent and/or severe stomach pain
• Urgent need to have bowel movements or accidents
• Restriction of normal daily activities due to IBS

The following prescription drugs are recommended for managing IBS-D by experts at the American Gastroenterological Association.

Alosetron

The Food and Drug Administration (FDA) approved Lotronex (alosetron) for use in adult females with chronic IBS-D who’ve had IBS symptoms for at least six months and haven’t responded to other treatments. This medication is not approved for use in children or adult males, as it has not been shown to be effective in these populations.

Alosetron comes in an oral tablet, with a typical starting dosage of 0.5 mg twice daily. After four weeks, the dose may be increased to 1 mg twice daily. If this dosage doesn’t help control your IBS symptoms within four weeks, your healthcare provider will likely have you stop the medication.

Common side effects of alosetron include constipation, abdominal pain, and nausea.

Rare but serious complications may occur as a result of prolonged constipation. Reach out to a healthcare provider if constipation lasts longer than usual or results in pain. People with constipation problems and those taking a medication called fluvoxamine should not take alosetron.

Eluxadoline

Viberzi (eluxadoline) is another treatment option for IBS-D. This prescription-only medication is FDA-approved for use in adults.

Eluxadoline comes as an oral tablet. The typical dosage is 100 mg twice a day. A lower dosage of 75 mg twice daily is recommended for people with liver or kidney problems, those unable to tolerate the 100 mg dose, and those taking certain medications that interact with eluxadoline, such as Neoral (cyclosporine).

Common side effects of eluxadoline are constipation, nausea, and abdominal pain. If severe constipation occurs, contact a healthcare professional right away. Eluxadoline is not a safe option for everyone and shouldn’t be taken by individuals with:

• Constipation problems
• Gallbladder or biliary duct problems
• History of pancreatitis (inflammation in the pancreas)
• Frequent alcohol use or alcohol use disorder
  

Rifaximin

Xifaxan (rifaximin) is a prescription-only antibacterial drug that is FDA-approved for the short-term treatment of IBS-D in adults.

This medication is also FDA-approved for other uses, including traveler’s diarrhea caused by Escherichia coli (E. coli).

To treat IBS-D, the typical dosage of rifaximin is 550 mg tablet three times per day for 14 days. If the diarrhea continues, a healthcare provider may prescribe up to two more rounds of treatment.

Common side effects of Xifaxan in people with IBS-D include nausea and elevated liver enzymes. Rarely, it may increase the risk of another severe type of diarrhea caused by the bacteria Clostridioides difficile (C. diff, previously known as Clostridium difficile).

When Do You Need a Prescription vs. OTC Medicine for Diarrhea?

In most cases, acute (short-term or occasional) diarrhea can be effectively managed with OTC anti-diarrhea medication.

Taking Imodium A-D or bismuth subsalicylate usually manages diarrhea quickly, typically stopping your symptoms within a day or two. If diarrhea continues for over two days while taking an OTC antidiarrheal, stop taking the product and contact a healthcare provider for advice. Seek immediate medical care if symptoms of dehydration develop.

If other symptoms accompany your diarrhea, such as fever, vomiting, abdominal pain, or bloating, consult a healthcare professional before taking an OTC medication.

How to Manage Diarrhea Symptoms

When you have diarrhea, drinking plenty of fluids is the best way to prevent dehydration. When you have diarrhea, your body loses a lot of water and electrolytes.

Signs of dehydration include headaches, feeling dizzy, or your heart beating abnormally. The best drinks to help with rehydration are oral rehydration solutions (ORS). They provide a balanced mix of sugars and salts. But if you can't get ORS, other liquids like water, juice, sports drinks with electrolytes, and soups can also help.

The BRAT diet (bananas, rice, applesauce, toast) is a helpful option for reintroducing solid foods if you have diarrhea. It consists of bland foods that are easy to digest

A healthcare professional can help determine whether other lifestyle changes are worth trying for chronic or more frequent diarrhea. For example, they may recommend an elimination diet to determine if certain foods trigger your symptoms.

Summary

Diarrhea is usually temporary and resolves on its own, but OTC medications like Imodium A-D and Pepto-Bismol can provide relief.

For chronic or frequent diarrhea linked to conditions like IBS-D, prescription medications may be necessary. It's important to follow dosage instructions and consult a healthcare professional if needed.

If diarrhea persists for more than two days or is accompanied by other symptoms, seeking medical advice is recommended.