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Key takeaways
Lomotil (diphenoxylate/atropine) requires a prescription, while Imodium (loperamide) is available over the counter for treating acute and chronic diarrhea.
Lomotil and Imodium work by slowing intestinal movement, but they contain different active ingredients, have different side effects, and have different drug interaction profiles.
Imodium may be more effective than Lomotil in treating diarrhea. Some studies suggest it has fewer side effects and may be better tolerated.
Both medications should be used with caution, considering their potential for serious side effects. Consult your healthcare provider for appropriate treatment.
Lomotil (diphenoxylate/atropine) and Imodium (loperamide) are two antidiarrheal medications that are used to treat acute and chronic diarrhea. These medications work in similar ways to decrease the number and frequency of bowel movements. Lomotil and Imodium are designed to be taken for short-term diarrhea, which usually resolves within a few days after taking the medication.
In many cases, diarrhea, although an unpleasant experience, is often mild and goes away on its own. The primary treatment for diarrhea is replacing fluids and electrolytes in order to prevent dehydration. However, medications like Lomotil and Imodium can be useful for acute diarrhea as well as chronic diarrhea associated with irritable bowel syndrome (IBS).
Despite their similarities in uses, Lomotil and Imodium have some differences to be mindful of. For example, these drugs contain different ingredients and have certain limitations. We’ll explore their differences and similarities here.
What are the main differences between Lomotil and Imodium?
Lomotil
Lomotil is a brand-name drug that can only be obtained with a prescription. 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 stylized as Imodium A-D, is the brand name for loperamide. Unlike Lomotil, Imodium can be purchased over the counter (OTC). Therefore, it’s more widely available.
Loperamide is a synthetic opioid that binds to opioid receptors in the intestinal wall to slow gut movement. It also blocks a chemical called acetylcholine and leads to decreased fluid and electrolyte loss. Because Imodium has minimal absorption in the central nervous system (CNS), it produces less CNS side effects that are common with other opioids, including diphenoxylate.
| Main differences between Lomotil and Imodium | ||
|---|---|---|
| Lomotil | Imodium | |
| Drug class | Antidiarrheal | Antidiarrheal |
| Brand/generic status | Brand and generic version available | Brand and generic version available |
| What is the generic name? | Diphenoxylate/Atropine | Loperamide |
| What form(s) does the drug come in? | Oral tablet Liquid solution |
Oral tablet Oral capsule Liquid suspension |
| What is the standard dosage? | Acute diarrhea: 2 tablets (2.5 mg diphenoxylate/0.025 mg atropine) four times daily until initial control of diarrhea has been achieved. Chronic diarrhea: Reduce the initial dosage to a maintenance dose (usually 2 tablets daily) as directed by a doctor. Discontinue if symptoms do not improve within 10 days. |
Acute diarrhea: 4 mg initially, and then 2 mg after each loose stool. Maximum daily dose: 16 mg Chronic diarrhea: Use a maintenance dose of 4 to 8 mg per day. Discontinue if symptoms do not improve within 10 days. |
| How long is the typical treatment? | Short-term diarrhea that resolves within 10 days. Long-term use may be needed for chronic diarrhea. | Short-term diarrhea that resolves within 10 days. Long-term use may be needed for chronic diarrhea. |
| Who typically uses the medication? | Adults and children 13 years of age and older. | Adults and children 2 years of age and older. Children under 6 years old should consult with a doctor before taking Imodium liquid. |
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Conditions treated by Lomotil and Imodium
Lomotil is FDA-approved as an adjunctive treatment for diarrhea. This means that Lomotil is recommended as additional therapy along with primary treatment methods such as preventing dehydration.
Like Lomotil, Imodium is FDA-approved to treat several types of diarrhea. Imodium can be used to treat Traveler’s diarrhea as well as diarrhea caused by medications like chemotherapy. Lomotil and Imodium can also treat chronic diarrhea caused by irritable bowel syndrome (IBS).
Diarrhea is typically defined as having loose stools three or more times in one day. Acute diarrhea is often mild and usually lasts no more than one or two days. Food poisoning is one of the most common causes of acute diarrhea.
Chronic diarrhea is more severe and can last for more than four weeks at a time. Symptoms of diarrhea can go away on their own or last for much longer, which may require treatment with medication.
| Condition | Lomotil | Imodium |
| Acute diarrhea | Yes | Yes |
| Traveler’s diarrhea | Yes | Yes |
| Chronic diarrhea | Yes | Yes |
| Chemotherapy-related diarrhea | Yes | Yes |
Is Lomotil or Imodium more effective?
Lomotil and Imodium are the most commonly used antidiarrheal agents. They are both effective and work relatively quickly to relieve symptoms of diarrhea. The best drug for you will depend on your overall condition, which should be assessed by your healthcare provider.
That being said, Imodium may be the more effective medication. Although there are no clinical trials that directly compare Lomotil and Imodium, some studies suggest that Imodium is a preferred option for treating diarrhea. One double-blind, crossover study found that loperamide was superior to diphenoxylate for treating diarrhea even at a 2.5-fold lower dose.
Another crossover study compared loperamide, diphenoxylate, and codeine for treating chronic diarrhea. Before treatment, 95% of participants experienced urgency as their main symptom of diarrhea. The study found that loperamide and codeine were more effective than diphenoxylate for relief. Diphenoxylate was found to have the most side effects while loperamide was shown to have the least.
Coverage and cost comparison of Lomotil vs. Imodium
Most Medicare Part D 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 $38. Check with your pharmacy to see if you can use a discount savings card. SingleCare Lomotil coupons can lower the cost so that you pay around $12.
Imodium is an OTC drug that might not be covered by Medicare and insurance plans. 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 $26. With a SingleCare discount, you can get generic loperamide tablets for about $14. In order to take advantage of OTC savings, you’ll still have to get a prescription from your doctor.
| Lomotil | Imodium | |
| Typically covered by insurance? | No | No |
| Typically covered by Medicare? | No | No |
| Standard dosage | 2.5 mg diphenoxylate/0.025 mg atropine, quantity of 30 tablets | 2 mg, quantity of 30 tablets |
| Typical Medicare copay | $0–$150 | $0–$99 |
| SingleCare cost | $12 | $14 |
Common side effects of Lomotil vs. Imodium
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 or stomach cramps.
In higher doses, serious side effects of Lomotil and Imodium could include severe drowsiness, hallucinations, and lethargy. Serious side effects like slowed breathing (respiratory depression) can also occur with toxic doses.
| Lomotil | Imodium | |||
| Side Effect | Applicable? | Frequency | Applicable? | Frequency |
| Constipation | No | – | Yes | 5.3% |
| Dizziness | Yes | *not reported | Yes | 1.4% |
| Nausea | Yes | * | Yes | 1.8% |
| Stomach cramps | Yes | * | Yes | 1.4% |
| Vomiting | Yes | * | Yes | * |
| Dry mouth | Yes | * | Yes | * |
| Drowsiness | Yes | * | Yes | * |
| Headache | Yes | * | No | – |
| Restlessness | Yes | * | No | – |
| Confusion | Yes | * | No | – |
This may not be a complete list of adverse effects that can occur. Please refer to your doctor or healthcare provider to learn more.
Source: DailyMed (Lomotil), DailyMed (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.
Unlike Lomotil, Imodium is more heavily processed in the liver by enzymes such as the CYP3A4 enzyme and CYP2C8 enzyme. Drugs that inhibit, or block, these enzymes can increase the levels of Imodium in the blood. As a result, taking these drugs together can increase the risk of adverse side effects.
| Drug | Drug Class | Lomotil | Imodium |
| Selegiline Phenelzine Isocarboxazid Tranylcypromine |
Monoamine oxidase inhibitors (MAOIs) | Yes | No |
| Phenobarbital Pentobarbital Alprazolam Lorazepam Trazodone Oxycodone |
CNS depressants | Yes | Yes |
| Saquinavir Itraconazole |
CYP3A4 inhibitors | No | Yes |
| Gemfibrozil | CYP2C8 inhibitors | No | Yes |
| Quinidine Ritonavir |
P-glycoprotein inhibitors | No | Yes |
This is not a complete list of drug interactions. Please consult your doctor before taking these medications.
Warnings of Lomotil and Imodium
Lomotil should not be used in children younger than 6 years of age due to an increased risk of respiratory and CNS depression. Those with obstructive jaundice or a known hypersensitivity to diphenoxylate or atropine should also avoid using Lomotil.
Imodium has been reported to cause Torsades de Pointes, cardiac arrest, and death when taken in higher than recommended doses. It’s recommended to only 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 bacterial infections. These drugs should not be used to treat diarrhea that is caused by organisms such as Clostridium difficile and Salmonella.
Consult your doctor if you have any medical conditions before taking these medications. It’s recommended to take these medications with medical advice from your healthcare provider.
Frequently asked questions about Lomotil vs. Imodium
What is Lomotil?
Lomotil is a prescription drug used as adjunctive therapy for diarrhea. Lomotil is available in brand-name and generic versions. It can be taken for acute or chronic diarrhea in adults and children who are 13 years of age and older.
What is Imodium?
Imodium is an over-the-counter (OTC) drug that is FDA-approved to treat diarrhea. Imodium is typically used to treat Traveler’s diarrhea although it can also treat chronic diarrhea caused by IBS. Imodium can treat adults and children who are 2 years of age and older.
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. Imodium can be purchased over the counter.
Is Lomotil or Imodium better?
Lomotil and Imodium are both effective drugs to treat diarrhea. Some research has shown that there is no significant difference in effectiveness between the two. However, other studies have shown that Imodium is more effective and better tolerated. Consult your doctor for the best treatment option that’s right for you.
Can I use Lomotil or Imodium while pregnant?
Some doctors may allow the use of Lomotil or Imodium during pregnancy only if it is necessary. Otherwise, Lomotil and Imodium are not generally recommended during pregnancy due to the possibility of fetal harm. Talk to your doctor for antidiarrheal options while pregnant.
Can I use Lomotil or Imodium with alcohol?
It is not recommended to drink alcohol while using Lomotil or Imodium. Lomotil and Imodium may cause adverse effects such as drowsiness and dizziness. Drinking alcohol can increase these side effects.
Why is Lomotil banned?
Lomotil is not a banned drug. However, it is a Schedule V controlled substance as classified by the DEA. 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 high potential for abuse.
Can you take Lomotil long term?
Lomotil is not recommended to be used for more than 10 days for acute diarrhea. In some cases, Lomotil can be used for long-term use, especially for chronic diarrhea. Long-term use of Lomotil should be monitored by a doctor.
What happens if Imodium doesn’t stop diarrhea?
Imodium should relieve symptoms of mild diarrhea within 48 hours. If you experience any of the following, you should call your doctor immediately:
- Blood in the stool
- Fever or temperature above 101.3°F
- Severe abdominal pain
- Passing six or more loose stools per day
- Diarrhea that lasts longer than 48 hours
- Symptoms such as severe lightheadedness, confusion, chest pain, or malaise