Over-the-counter medication · Antidiarrheal (Opioid Receptor Agonist)
loperamide
Also sold as Imodium. This medicine treats diarrhea.
Data updated 2026-05-15
- 42,665
- FDA reportsOften reported
- 2
- InteractionsFew interactions
- 1
- Recall record
What the data shows
loperamide (Imodium) is an over-the-counter Antidiarrheal (Opioid Receptor Agonist), reported at a middle-of-the-pack volume (42,665 FDA reports), with 2 documented drug interactions.
Reporting volume reflects how widely a drug is used and studied, not how dangerous it is, a FAERS report documents a temporal association, never proof of cause.
loperamide (Imodium) is an over-the-counter Antidiarrheal (Opioid Receptor Agonist). This medicine treats diarrhea.
Loperamide (Imodium) helps control diarrhea symptoms. It is also used for Traveler's Diarrhea.
Verify with FDA → · CMS NADAC pricing →
Drug Pricing (NADAC)
Generic Price
$0.03/unit
Generic Available
Yes (23 manufacturers)
Pricing data from NADAC (CMS), effective December 18, 2024. Compare all drug costs →
What it does
This medicine treats diarrhea.
Common side effects
Headache, Dizziness, Constipation
Key warnings
Taking too much loperamide can cause serious heart problems.
The sections below are summarized in plain English from loperamide's FDA-approved prescribing information. They describe what the official label says, and are not personal medical advice.
How It Works
Loperamide works by slowing down your intestines. This allows more water to be absorbed from your stool. This makes your stools less watery and reduces how often you need to go to the bathroom.
Side Effects (from patient reports)
Based on 42,665 FDA adverse event reports.
Most-reported reactions
Adverse reactions in FAERS for loperamide, by number of reports
- Diarrhoea
Diarrhoea
8,463 reports
- Nausea
Nausea
4,092 reports
- Fatigue
Fatigue
3,690 reports
- Vomiting 2,674
Vomiting
2,674 reports
- Constipation 2,352
Constipation
2,352 reports
- Weight Decreased 2,018
Weight Decreased
2,018 reports
- Headache 1,890
Headache
1,890 reports
- Dyspnoea 1,879
Dyspnoea
1,879 reports
- Abdominal Pain 1,759
Abdominal Pain
1,759 reports
- Asthenia 1,745
Asthenia
1,745 reports
What this shows Bars show how often each reaction was reported, not how likely it is to happen, a report records a temporal association, never proof that the drug caused it.
Reports over time
Adverse-event reports filed for loperamide each year to the FDA Adverse Event Reporting System (FAERS).
Year-to-year volume tracks usage, prescribing, and scrutiny, not a change in per-patient risk. Source: FDA FAERS.
Where loperamide sits
loperamide has more FDA adverse-event reports than 70% of the drugs FAERS tracks. A high position reflects how widely a drug is used and watched, not how dangerous it is.
Percentile across all drugs PlainMeds tracks by FAERS report volume. The dot is loperamide; the line is the median (50th percentile).
FDA Adverse Event Report Analysis
Detailed analysis of 42,665 reports from the FDA Adverse Event Reporting System (FAERS). Reports span 1999–2025.
Total Reports
42,665
Reports Mentioning Death
3,775
8.8% of reports — not proof of cause
Hospitalization Reports
15,486
Top Indication
Product Used For Unknown Indication
Gender Distribution
Age Distribution
Most Reported Adverse Reactions (FAERS)
| # | Reaction | Reports |
|---|---|---|
| 1 | DIARRHOEA | 8,463 |
| 2 | NAUSEA | 4,092 |
| 4 | FATIGUE | 3,690 |
| 6 | VOMITING | 2,674 |
| 7 | CONSTIPATION | 2,352 |
| 8 | WEIGHT DECREASED | 2,018 |
| 9 | HEADACHE | 1,890 |
| 10 | DYSPNOEA | 1,879 |
| 11 | ABDOMINAL PAIN | 1,759 |
| 12 | ASTHENIA | 1,745 |
| 13 | DECREASED APPETITE | 1,712 |
| 14 | DIZZINESS | 1,615 |
| 15 | PAIN | 1,595 |
| 16 | PNEUMONIA | 1,545 |
| 17 | DEHYDRATION | 1,533 |
Reactions in Death Reports
Reactions in Hospitalization Reports
Source: FDA FAERS (Adverse Event Reporting System) Reports are voluntary and do not establish causation
Serious Warnings
Taking too much loperamide can cause serious heart problems. Always follow the recommended dose.
Known Drug Interactions
Examples: cyclosporine, gemfibrozil, antiretrovirals (atazanavir, lopinavir, ritonavir, saquinavir, tipranavir), rifampin, eltrombopag Drugs that Cause Constipation Clinical Impact: Increased risk for constipation related adverse reactions and potential for constipation related serious adverse reactions Intervention: Avoid use with other drugs that may cause constipation (see below); loperamide may be used occasionally for acute management of severe diarrhea but avoid chronic use. Discontinue loperamide immediately if constipation occurs.
Mechanism: These medicines both work to slow down your bowels, and using them together can cause dangerous levels of constipation.
Aprepitant Loperamide a Monitor for adverse reactions.
Mechanism: Itraconazole can stop your body from breaking down loperamide properly, leading to higher levels of the medicine in your blood.
This is a plain-language summary of FDA-label interaction records and does not provide individual medication-combination directions.
Common Questions
How much should I take?
Can I use a regular spoon to measure the dose?
What should I do if I still have diarrhea after taking this medicine?
Can I take this medicine if I have a fever?
Can I take this with other medicines?
What is the maximum amount I can take in a day?
Can children under 2 years old take this medicine?
What do I do if I accidentally take too much?
Does this medicine expire?
Can I drive while taking this medicine?
What are the common side effects of loperamide?
Does loperamide interact with other medications?
What drug class is loperamide?
What pregnancy or breastfeeding source fields are listed for loperamide?
Has loperamide been recalled?
Active Recalls
CGMP Deviations: product held outside appropriate storage temperature conditions.
Family Dollar Stores, Llc.
Related Medications in Antidiarrheal (Opioid Receptor Agonist)
Other drugs grouped near loperamide - 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 loperamide →
aprepitant
Emend
Aprepitant (Emend) is a medicine that helps prevent nausea and vomiting.
Compare with loperamide →
bisacodyl
Dulcolax
Bisacodyl is a medicine that helps you have a bowel movement.
Compare with loperamide →
bismuth subsalicylate
Pepto-Bismol
Bismuth subsalicylate (Pepto-Bismol) is a medicine that can treat diarrhea and upset stomach.
Compare with loperamide →
cimetidine
Tagamet
Cimetidine (Tagamet) reduces stomach acid.
Compare with loperamide →
Compare beyond drug class
Nationwide peers by FAERS volume & death-report share
Two PlainMeds-derived comparison paths for loperamide: nearest FDA FAERS report volume and nearest death-report share among drugs with at least 1,000 logged reports, excluding same-class neighbors listed above. Counts reflect reporting volume, not proven individual harm.
Similar FAERS report volume
Nearest drugs by total FAERS reports. This record: 42,665.
Similar death-report share
Nearest drugs by FAERS death-report share. This record: 8.85%.
- dexlansoprazole Δ 0.01 pts · 40,790 reports · Proton Pump Inhibitor (PPI) 8.84%death share
- glyburide Δ 0.03 pts · 23,902 reports · Sulfonylurea 8.88%death share
- pravastatin Δ 0.03 pts · 18,936 reports · HMG-CoA Reductase Inhibitor (Statin) 8.81%death share
- ertapenem Δ 0.04 pts · 3,848 reports · Carbapenem Antibiotic 8.81%death share
Medication Guides
Understanding Drug Interactions
How CYP450 enzymes, inhibitors, and inducers affect your medications
Generic vs Brand Name Drugs
FDA requirements, cost savings, and when the difference matters
Pain Relievers Compared
NSAIDs vs acetaminophen, which OTC pain reliever to use
Narrow Therapeutic Index Drugs
FDA bioequivalence and label-record context for narrow therapeutic index medicines
Common Drug Interactions
Dangerous medication combinations and how to protect yourself
What the FDA Data Shows for loperamide
The FDA label for loperamide (sold under brand names such as Imodium) classifies it as an over-the-counter product in the Antidiarrheal (Opioid Receptor Agonist) class. This medicine treats diarrhea. Official labeling lists 4 commonly reported side effects, including Headache, Dizziness, Constipation.
Post-market surveillance from the FDA Adverse Event Reporting System (FAERS) captures real-world experience. For this drug, FAERS contains 42,665 voluntary reports. The database also lists 2 documented drug interactions derived from FDA labeling, with the top-flagged interaction rated moderate severity. NADAC pricing from CMS shows a generic unit cost of $0.03.
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 (currently 1 recall record on file), and patent information are separate source-record fields. This page is a public FDA/CMS registry and does not provide medical, treatment, substitution, or medication-change directions.
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. This registry does not provide medication decisions.
Last updated: April 11, 2025
PlainMeds is rendered directly from FDA openFDA/FAERS extracts, DailyMed labels, and CMS drug-pricing files, no number is typed in by an editor. FAERS counts, recalls, shortages, and price figures on this page are queried live from those federal extracts. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of 2026-05-15. Primary sources: openFDA / FAERS, DailyMed and CMS Part B ASP.
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 from the source snapshot dated . See our methodology for per-source dates and refresh cadence. Spot a figure that looks wrong? Report a data issue.
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