Got Diarrhea? Medication Side Effects to Watch for
Find out how Imodium, Pepto-Bismol, and other anti-diarrheal drugs work, their risks, and when to get medical help.
By Thomas Leeson, DO, Virtua Urgent Care
From cyclospora to salmonella, norovirus to rotavirus, stomach illnesses are becoming more common with contaminated food and water sources.
Over-the-counter medications are often people’s first stop for treating diarrhea in order to get back to school or work or just find relief in general. While these drugs will help slow frequent bowel movements and calm your intestines, they may not resolve your condition—and could have harmful side effects if not taken as directed.
Before taking any medication, always read the warning labels. You can also speak to a pharmacist, and tell them what other prescription and over-the-counter medications, herbals, and supplements you are taking.
Why do I have diarrhea?
Normally, the intestines contract rhythmically to move food and fluids through the digestive system, allowing enough time for the absorption of nutrients and water and the creation of formed stool.
When you have diarrhea, triggered by an irritant or infection, intestinal contractions occur more quickly, causing food to pass through too rapidly without time to digest. There is not enough time for food to digest, leading to loose, watery stool.
What are the side effects of anti-diarrheal drugs?
When used too frequently and in higher quantities, the ensuing side effects of anti-diarrheal medications are not innocent. Young children are especially susceptible to medication overuse, with an immature barrier between their blood and brain, magnifying otherwise mild side effects in adults.
The following are common anti-diarrheal drugs to watch for and potential side effects:
Loperamide
- Brand names: Imodium, Maalox Anti-Diarrheal, Kaopectate II
- Available in both tablet and liquid forms, with a maximum daily adult limit of 16 mg and just 3 mg a day for a child
- Slows the movement of the intestines, restoring stool’s normal consistency, reducing the frequency of bowel movements, and preventing dehydration
- Loperamide keeps the irritating trigger in your body, potentially extending the duration of your illness. And even at doses less than the daily maximum, loperamide can cause irregular heart rhythms and even induce the effects of a narcotic overdose, like slowing your breathing and lethargy.
Bismuth subsalicylate
- Brand names: Pepto-Bismol, Kaopectate
- Available in liquid, capsules, chewable, and dissolvable forms
- Coats the stomach lining, preventing the triggering irritant from causing inflammation that can cause diarrhea. It also helps to neutralize stomach acid that leads to heartburn, nausea, and indigestion.
- As bismuth subsalicylate encounters sulfur present in your gut, a black coating of your stool develops. Having black stool can mask signs of gastrointestinal bleeding, possibly leading to missed diagnoses.
- With its close similarity to aspirin, unintentional overdose and bleeding are possible with over-the-counter ibuprofen (Advil, Motrin) and naproxen (Alleve) and common blood thinners like warfarin (Coumadin), apixaban (Eliquis), or rivaroxaban (Xarelto).
- Some antibiotics are rendered ineffective, like tetracyclines or fluoroquinolones. Some diabetes medications can interact, causing a dangerously low blood sugar (hypoglycemia).
Diphenoxylate-Atropine
- Brand names: Diafort, Lomotil
- Available in tablet and liquid forms, prescribed for severe diarrhea cases
- Slows the movement of the intestines
- When overused, this combination of medication can have a cascade of problems. Early symptoms of an overdose may include racing or irregular heartbeats; hot flushing of the skin; high fever; enlarged pupils and blurry vision; and anxiety, confusion, and hallucinations. As the overdose progresses, symptoms may include severely slowed breathing; cessation of digestion and bowel movements; seizures and coma. Seek immediate medical help.
How do I safely treat diarrhea?
- Take natural fiber supplements. Metamucil contains psyllium husk, a soluble fiber that absorbs water in the intestines, thickens loose stools, and slows the digestive tract. It comes in a palatable orange gum drop form.
- Drink plenty of fluids with electrolytes to prevent dehydration and replace the loss of vital ions and salts. Brands include Pedialyte and Gatorade.
- Take probiotics to restore the balance of bacteria in your gut. Probiotics are naturally found in fermented foods such as yogurt and kimchi, as well as in capsule form.
- Eat bland foods, such as the BRAT diet (bananas, rice, applesauce, and toast), broth, and plain crackers.
When should I get help for my diarrhea?
If your diarrhea is mild and chronic, schedule a primary care appointment or a gastroenterologist appointment online or call 888-847-8823.
If your symptoms are mild and last just a few days without signs of dehydration like dizziness, dry mouth, or rapid heart rate, Virtua urgent care may be able to support you. Find one of our urgent care locations near you. If you are in severe distress, seek medical attention at one of Virtua’s emergency rooms.
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