Key takeaways
Lomotil and Imodium are two medications used to treat diarrhea. While both are considered effective, they have key differences to be mindful of.
Lomotil is a prescription drug and is classified as a Schedule V controlled substance. Imodium is sold over the counter.
The side effect profile of each drug is somewhat similar, but Lomotil can cause more central nervous system adverse events, such as drowsiness and confusion.
If you’re trying to decide between Lomotil and Imodium, both antidiarrheal medications can help reduce loose stools, but they aren’t interchangeable. Imodium (loperamide) is available over the counter and is usually the first choice for short-term diarrhea. At the same time, Lomotil (diphenoxylate/atropine) is a prescription medication typically reserved for more severe cases. Here’s how they compare in effectiveness, side effects, cost, and safety.
Lomotil vs. Imodium at a glance |
|
|---|---|
| If you want… | Choose |
| An over-the-counter option | Imodium |
| Prescription treatment for severe diarrhea | Lomotil |
| Fewer side effects | Imodium |
| Lower abuse potential | Imodium |
| Treatment supervised by a healthcare provider | Lomotil |
What are the main differences between Lomotil and Imodium?
Lomotil
Lomotil is a brand-name drug that can only be obtained with a prescription, and generic versions are available as well. It contains a combination of diphenoxylate (an opioid) and atropine (an anticholinergic drug).
Diphenoxylate is the primary ingredient that binds to opioid receptors in the gut to slow intestinal motility. Atropine is added to discourage drug abuse since diphenoxylate is a controlled substance on its own.
Imodium
Imodium, also called Imodium A-D, is the brand name for loperamide. Unlike Lomotil, Imodium can be purchased over the counter (OTC) in both brand and generic versions. Therefore, it’s more widely available.
Loperamide’s chemical structure is similar to that of an opioid. It binds to opioid receptors in the intestinal wall, slowing gut motility. It also blocks a chemical called acetylcholine, leading to decreased fluid and electrolyte loss. Because Imodium has minimal absorption in the central nervous system (CNS), it produces fewer CNS side effects than Lomotil, which has the opioid diphenoxylate as a primary ingredient. In addition to treating diarrhea, it is sometimes used to reduce stool output in people who have had an ileostomy.
Main differences between Lomotil and Imodium |
||
|---|---|---|
| Feature | Lomotil | Imodium |
| Prescription required | Yes | No |
| OTC available | No | Yes |
| Works quickly | Yes | Yes |
| Controlled substance | Yes | No |
| First-line treatment | Usually no | Yes |
| Abuse potential | Higher | Lower |
| Common side effects | Drowsiness | Constipation |
| Best for | Severe or persistent cases | Acute diarrhea |
How long does it take Lomotil vs. Imodium to work?
Lomotil starts working within a few hours, but it may take about 2 days (48 hours) to see improvement in diarrhea.
Imodium typically starts to work within one hour.
Is Lomotil or Imodium more effective?
Lomotil and Imodium are commonly used antidiarrheal agents. They are both effective and work relatively quickly to relieve diarrhea symptoms. The best drug for you will depend on your overall condition and medical history, which your healthcare provider should assess.
There are no recent clinical studies that compare the effectiveness of these two drugs. In 2016, the American College of Gastroenterology (ACG) published a clinical guideline for managing acute diarrhea in adults. In this guideline, the ACG noted that the major antimotility drugs for acute diarrhea are Lomotil and Imodium. They state that of the two drugs, Imodium (loperamide) is considered “the most useful drug” because it has fewer central nervous system effects. Also, Lomotil contains atropine, which is an abuse deterrent but does not help with diarrhea, and it may cause additional side effects.
Imodium may be better if:
- You have acute diarrhea
- You need OTC treatment
- You want fewer CNS side effects
- You need travel medication
- You need quick symptom relief
Lomotil may be better if:
- OTC medications haven’t worked
- Your provider recommends prescription therapy
- You have chronic diarrhea/loose bowel movements
Most people with uncomplicated diarrhea will start with Imodium because it’s effective, inexpensive, available without a prescription, and generally causes fewer nervous system side effects than Lomotil. With either drug, fluids are typically recommended, as tolerated, to help prevent dehydration.
Coverage and cost comparison of Lomotil vs. Imodium
Compare Lomotil vs. Imodium A-D prices with SingleCare
Different pharmacies offer different prices for the same medication. SingleCare helps find the best price for you.
Most Medicare and insurance plans do not cover brand-name Lomotil. However, many insurance plans cover the generic version of the drug. Medicare Part D plans should cover diphenoxylate/atropine depending on your coverage. The average retail cost of generic Lomotil is around $130 for 30, 2.5/0.025 mg tablets. Check with your pharmacy to see if you can use a discount savings card. SingleCare Lomotil coupons can lower the cost, so you can pay as little as $14 for generic Lomotil at Kroger.
Imodium is an OTC drug that Medicare and insurance plans might not cover. Some plans may cover the generic form with a prescription. It’s best to check your insurance plan’s formulary to make sure. The average cost of loperamide is around $21. With a SingleCare discount, you can get generic loperamide tablets for as low as $10 at Food Lion. In order to take advantage of OTC savings, you’ll still have to get a prescription from your healthcare provider.
Compare coverage and cost of Lomotil vs. Imodium |
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|---|---|---|
| Category | Lomotil | Imodium |
| Typically covered by insurance? | Brand-name Lomotil may not be covered, but generic versions typically are covered | No |
| Typically covered by Medicare? | Brand-name Lomotil may not be covered, but generic versions typically are covered | No |
| Standard dosage | 2.5 mg diphenoxylate/0.025 mg atropine, quantity of 30 tablets | 2 mg, quantity of 24 tablets |
| SingleCare cost | See latest prices | See latest prices |
Common side effects of Lomotil vs. Imodium
According to its prescribing information, side effects of Lomotil include drowsiness, dizziness, and nausea. Compared to Imodium, Lomotil may have more CNS side effects, including headache, restlessness, and confusion.
The most common side effect associated with Imodium is constipation. Other common side effects include dizziness, nausea, and abdominal cramps, according to StatPearls.
Serious side effects of Imodium can include toxic megacolon, fainting, and severe skin reactions. Serious heart problems, including irregular rhythms, cardiac arrest, and death, have been reported with higher-than-recommended doses of Imodium.
Drug interactions of Lomotil vs. Imodium
Lomotil can interact with drugs like monoamine oxidase inhibitors (MAOIs) and CNS depressants. Taking an MAOI, like selegiline or phenelzine, with Lomotil may increase the risk of hypertensive crisis, or dangerously high blood pressure. The risk of adverse effects may also be increased while taking CNS depressant drugs like barbiturates, benzodiazepines, and muscle relaxants.
Imodium has many potential drug interactions. Unlike Lomotil, Imodium is primarily metabolized in the liver by the CYP3A4 enzyme. Drugs that inhibit or block this enzyme, such as ketoconazole, atazanavir, verapamil, and clarithromycin, can increase Imodium levels in the blood. As a result, taking any of those drugs with Imodium can increase the risk of adverse side effects. Imodium may also interact with drugs such as amiodarone, carvedilol, and quinidine, according to StatPearls.
Warnings of Lomotil and Imodium
Lomotil should not be used in children less than 6 years of age due to an increased risk of respiratory and CNS depression. Lomotil is FDA-approved for use in patients 13 years and older, so prescribing it to a child under 13 years old would be considered an off-label use. Those with obstructive jaundice or known hypersensitivity to diphenoxylate or atropine should also avoid using Lomotil.
Imodium has been reported to cause serious heart problems, such as Torsade de Pointes, cardiac arrest, and death when taken in higher than recommended doses. It’s recommended only to take the minimum required dosage as instructed by your healthcare provider. Imodium should not be used in toddlers and infants less than 2 years of age due to the risk of respiratory and CNS depression.
Lomotil and Imodium should not be used to treat diarrhea caused by certain types of bacterial infections.
Consult your healthcare provider if you have any medical conditions before taking these medications. It’s recommended to take these medications under the guidance of your healthcare provider.
Frequently asked questions about Lomotil vs. Imodium
Are Lomotil and Imodium the same?
No. Lomotil and Imodium are not the same. Although they work in similar ways, Lomotil can only be obtained with a prescription and is a Schedule V controlled substance. Imodium can be purchased over the counter.
Is Lomotil or Imodium better?
Lomotil and Imodium are both effective drugs for treating diarrhea. Imodium is often preferred as a first choice of treatment because it is readily available over the counter, but prescription Lomotil may be needed in some cases. Consult your healthcare provider to determine the best treatment option for you.
Can you take Lomotil and Imodium together?
Not usually. You should only take them together if instructed by a healthcare provider. Combining them can increase constipation and side effects.
Why is Lomotil banned?
Lomotil is not a banned drug. However, it is a Schedule V controlled substance as classified by the Drug Enforcement Administration. This means that there is a potential for misuse and abuse when using this drug. By itself, diphenoxylate, the main active ingredient of Lomotil, is a Schedule II substance with a higher potential for abuse.
Can you take Lomotil long-term?
Yes, in some cases, Lomotil can be used long-term, especially for patients with chronic diarrhea. A healthcare provider should monitor long-term use of Lomotil.
What happens if Imodium doesn’t stop diarrhea?
Imodium should relieve mild diarrhea symptoms within 48 hours. If your diarrhea isn’t improving after two days, stop taking Imodium and contact a healthcare provider. You should call your healthcare provider if your symptoms worsen, you have blood in the stool, severe stomach pain, or any other concerning symptoms.
The bottom line
For most adults with uncomplicated acute diarrhea, Imodium is often the preferred first option because it’s available over the counter, works quickly, and causes fewer central nervous system side effects. Lomotil may be appropriate when prescription treatment is needed or when symptoms don’t improve with Imodium, but it should only be used under the guidance of a healthcare provider.
The SingleCare prices in this article are the most accurate at the time of publishing in ZIP code 23666 as of Sep. 1, 2026. Prices vary by pharmacy. Visit our coupon page for updated drug prices at pharmacies near you.
- Diphenoxylate hydrochloride and atropine sulfate tablet, DailyMed (2025)
- Imodium A-D, DailyMed (2024)
- Traveler’s diarrhea, Centers for Disease Control and Prevention (2022)
- Chronic diarrhea, StatPearls (2023)
- Loperamide, StatPearls (2024)
- Torsade de Pointes, StatPearls (2023)
- ACG clinical guideline: Diagnosis, treatment, and prevention of acute diarrheal infections in adults, American Journal of Gastroenterology (2016)
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