diphenoxylate/atropine
Brand names: Lomotil
Lomotil is a drug that helps manage diarrhea. It contains two medicines, diphenoxylate and atropine, to slow down your bowels.
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 →
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.
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.
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.
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.
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
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.
Common Questions
Who should not take Lomotil?
Can I drink alcohol while taking Lomotil?
What should I do if Lomotil doesn't improve my diarrhea?
Can Lomotil cause constipation?
Can I take Lomotil with other medications?
What are the signs of an overdose?
How quickly does Lomotil work?
Can Lomotil cause allergic reactions?
Is Lomotil a cure for diarrhea?
What if I am taking an MAOI?
What are the common side effects of diphenoxylate/atropine?
Does diphenoxylate/atropine interact with other medications?
What drug class is diphenoxylate/atropine?
Is diphenoxylate/atropine safe during pregnancy?
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 →
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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.
All federal data sources used on this page
- FDA Orange Book — approved drug products with therapeutic equivalence. accessdata.fda.gov/cder/ob
- FDA DailyMed — NIH-hosted drug labeling for FDA-approved meds. dailymed.nlm.nih.gov
- FDA Adverse Event Reporting System (FAERS) — post-marketing safety surveillance. fda.gov/drugs/faers
- NLM RxNorm — standardized clinical drug nomenclature. nlm.nih.gov/research/umls/rxnorm
- CMS Medicare Part B Drug Average Sales Price Files — federal drug pricing data. cms.gov/medicare/part-b-drugs/asp
- FDA Drug Shortages Database — current and resolved drug shortage tracking. accessdata.fda.gov/drugshortages