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Prescription medication · Antidiarrheal Combination

diphenoxylate/atropine

Also sold as Lomotil. Lomotil is used to treat diarrhea in people 13 years and older.

Data updated 2026-05-15

1
InteractionFew interactions
$2.89
Brand price (NADAC)

diphenoxylate/atropine (Lomotil) is a prescription Antidiarrheal Combination. Lomotil is used to treat diarrhea in people 13 years and older.

Lomotil is a drug that helps manage diarrhea. It contains two medicines, diphenoxylate and atropine, to slow down your bowels.

Verify with FDA → · CMS NADAC pricing →

Drug Pricing (NADAC)

Brand Price

$2.89/unit

Generic Available

No

PFIZER

Pricing data from NADAC (CMS), effective December 18, 2024. Compare all drug costs →

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What it does

Lomotil is used to treat diarrhea in people 13 years and older.

Common side effects

Numbness in your arms and legs, Feeling of well-being, Depression

Key warnings

Lomotil can cause serious side effects, including breathing problems and nervous system issues.

The sections below are summarized in plain English from diphenoxylate/atropine's FDA-approved prescribing information. They describe what the official label says, and are not personal medical advice.

How It Works

Lomotil works by slowing down the movement of your intestines. Diphenoxylate reduces bowel contractions. Atropine is added to discourage people from taking too much of this medicine.

How to Take It

The usual starting dose is 2 tablets, 4 times a day. Do not take more than 8 tablets in 24 hours. Once your diarrhea is under control, you may need less medicine. You may only need 2 tablets a day to maintain control.

This is a plain-language summary of diphenoxylate/atropine's FDA labeling, not individualized dosing advice. Ask a pharmacist or prescriber before changing how you take this medication.

Pregnancy & Breastfeeding

It is not known if Lomotil can harm your unborn baby. Talk to your doctor if you are pregnant or plan to become pregnant. It is also not known if Lomotil passes into breast milk, so talk to your doctor if you are breastfeeding.

This is a plain-language summary of diphenoxylate/atropine's FDA labeling, not individualized advice. Ask a pharmacist or prescriber about pregnancy or breastfeeding on this medication.

Missed Dose

If you miss a dose, take it as soon as you remember. If it is close to your next dose, skip the missed dose and continue with your regular schedule.

This is a plain-language summary of diphenoxylate/atropine's FDA labeling, not individualized advice. Ask a pharmacist or prescriber what to do about your specific missed dose.

Storage

Store Lomotil tablets below 77°F (25°C).

Serious Warnings

Lomotil can cause serious side effects, including breathing problems and nervous system issues. Dehydration and electrolyte imbalance can also occur. If you have an infection causing your diarrhea, Lomotil can make it worse. Do not use if you are under 6 years old.

Known Drug Interactions

minor buspirone

Other Drugs that Cause CNS Depression The concurrent use of Lomotil with other drugs that cause CNS depression (e.g., barbiturates, benzodiazepines, opioids, buspirone, antihistamines, muscle relaxants), may potentiate the effects of Lomotil (see WARNINGS ).

Mechanism: Both of these medicines can slow down the central nervous system, and taking them together can make these drowsy effects much stronger.

What to do: Use caution when taking these together as they can cause extra sleepiness or dizziness.

This is a plain-language summary of interactions documented in FDA labeling, not individualized advice. Ask a pharmacist or prescriber before combining medications.

Common Questions

Who should not take Lomotil?
Children under 6 years old, people with certain types of diarrhea caused by infection, people with jaundice, and people allergic to diphenoxylate or atropine should not take Lomotil.
Can I drink alcohol while taking Lomotil?
No, avoid alcohol while taking Lomotil, as it can increase drowsiness.
What should I do if Lomotil doesn't improve my diarrhea?
If your diarrhea does not improve after 10 days of taking the maximum dose, stop taking Lomotil and talk to your doctor.
Can Lomotil cause constipation?
Yes, Lomotil can slow down your bowels too much and cause constipation.
Can I take Lomotil with other medications?
Lomotil can interact with other medicines that cause drowsiness, such as sleeping pills, antihistamines, and muscle relaxants. Tell your doctor about all the medicines you take.
What are the signs of an overdose?
Signs of overdose include slow breathing, confusion, rapid heartbeat, fever, and dry skin. Seek medical attention immediately if you suspect an overdose.
How quickly does Lomotil work?
You should see improvement in your diarrhea within 48 hours.
Can Lomotil cause allergic reactions?
Yes, allergic reactions such as rash, hives, and swelling can occur. Seek medical attention if you experience these symptoms.
Is Lomotil a cure for diarrhea?
No, Lomotil helps manage the symptoms of diarrhea. It is important to treat the underlying cause of your diarrhea.
What if I am taking an MAOI?
Avoid Lomotil if you take an MAOI or monitor for signs of high blood pressure.
What are the common side effects of diphenoxylate/atropine?
The most commonly reported side effects of diphenoxylate/atropine include Numbness in your arms and legs, Feeling of well-being, Depression, Feeling tired or weak, Confusion. Always consult your healthcare provider about potential side effects.
Does diphenoxylate/atropine interact with other medications?
Yes, diphenoxylate/atropine has 1 known drug interactions. Notable interactions include buspirone. Always inform your doctor about all medications you are taking.
What drug class is diphenoxylate/atropine?
diphenoxylate/atropine belongs to the Antidiarrheal Combination drug class. It requires a prescription (Rx). Lomotil is used to treat diarrhea in people 13 years and older.
Is diphenoxylate/atropine safe during pregnancy?
It is not known if Lomotil can harm your unborn baby. Talk to your doctor if you are pregnant or plan to become pregnant. Always consult your healthcare provider before using any medication during pregnancy or breastfeeding.

Related Medications in Antidiarrheal Combination

Other drugs grouped near diphenoxylate/atropine - same-class peers and common alternatives.

alosetron

Lotronex

Alosetron (Lotronex) is a medicine for women with severe diarrhea-predominant irritable bowel syndrome (IBS).

Compare with diphenoxylate/atropine →

aprepitant

Emend

Aprepitant (Emend) is a medicine that helps prevent nausea and vomiting.

Compare with diphenoxylate/atropine →

bisacodyl

Dulcolax

Bisacodyl is a medicine that helps you have a bowel movement.

Compare with diphenoxylate/atropine →

bismuth subsalicylate

Pepto-Bismol

Bismuth subsalicylate (Pepto-Bismol) is a medicine that can treat diarrhea and upset stomach.

Compare with diphenoxylate/atropine →

cimetidine

Tagamet

Cimetidine (Tagamet) reduces stomach acid.

Compare with diphenoxylate/atropine →

Compare diphenoxylate/atropine vs alosetron side-by-side →

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What the FDA Data Shows for diphenoxylate/atropine

The FDA label for diphenoxylate/atropine (sold under brand names such as Lomotil) classifies it as a prescription-only medication in the Antidiarrheal Combination class. Lomotil is used to treat diarrhea in people 13 years and older. Official labeling lists 9 commonly reported side effects, including Numbness in your arms and legs, Feeling of well-being, Depression.

Post-market surveillance from the FDA Adverse Event Reporting System (FAERS) captures real-world experience. Voluntary reports accumulate over the lifetime of a drug and reflect wide-ranging clinical use. The database also lists 1 documented drug interaction derived from FDA labeling, with the top-flagged interaction rated minor severity. NADAC pricing from CMS.

Report counts do not establish causation, a FAERS entry documents a temporal association, not proof that the drug produced the outcome. Widely prescribed medications naturally accumulate more reports than niche therapies, so raw totals must be interpreted alongside total exposure. Shortage status, recall history, and patent information further shape supply and switching decisions. This page summarizes public FDA data for educational purposes only and is not a substitute for professional medical advice, always consult a licensed healthcare provider before starting, stopping, or changing any medication.

Data Sources

Drug labeling: FDA Drug Labels (SPL/DailyMed). Adverse events: FDA Adverse Event Reporting System (FAERS). Pricing: CMS National Average Drug Acquisition Cost (NADAC).

FAERS reports are voluntary and do not establish causation. Drug interactions are derived from FDA labeling and clinical references. Always consult a healthcare professional before making medication decisions.

Last updated: April 3, 2025

Read our methodology - how this data is sourced, computed, and verified.

Data currency: FDA FAERS adverse-event reports through 2025, CMS NADAC acquisition-cost pricing effective December 2024, compiled and last refreshed May 2026. See our methodology for per-source dates and refresh cadence. Spot a figure that looks wrong? Report a correction.

All federal data sources used on this page