OpenClaim

Loperamide Side Effects

The most commonly reported side effects of loperamide include diarrhoea, nausea, and fatigue, based on 84,403 FDA adverse event reports from 2004 to 2025. 7.8% of reports found the drug to be ineffective.

Loperamide side effects

Percentages show how often each reaction appears relative to total reports for loperamide.

1
Diarrhoea15.6%13,150
2
Drug Ineffective7.8%6,545
3
Nausea7.7%6,469
4
Fatigue7.2%6,074
5
Off Label Use6.2%5,229
6
Vomiting5.2%4,362
7
Constipation4.1%3,466
8
Dyspnoea3.9%3,273
9
Weight Decreased3.8%3,245
10
Headache3.6%3,039
11
Decreased Appetite3.5%2,963
12
Asthenia3.2%2,743
13
Pyrexia3.2%2,659
14
Abdominal Pain3.1%2,655
15
Pain3.1%2,641

These are voluntary reports and do not establish that loperamide caused these reactions.

Report severity

67.2%Serious56,691 reports
39.7%Hospitalizations33,523 reports
10.6%Fatal8,925 reports

Seriousness is determined by the reporter, not by OpenClaim.

Loperamide drug interactions

Other drugs that appear in adverse event reports alongside loperamide. Drugs flagged as a suspected cause appear in the first column. Drugs taken at the same time but not suspected appear in the second.

Also suspected

1
Lenalidomide6.6%5,560
2
Simethicone6.3%5,300
3
Treprostinil3.4%2,828
4
Adalimumab3.3%2,790
5
Capecitabine2.7%2,267
6
Trastuzumab2.5%2,068
7
Fluorouracil2.1%1,794
8
Acetaminophen2.1%1,785
9
Prednisone2.1%1,755
10
Paclitaxel2.1%1,753
11
Oxaliplatin2.0%1,709
12
Infliximab2.0%1,681
13
Bevacizumab2.0%1,659
14
Irinotecan-hydrochloride1.8%1,551
15
Vedolizumab1.8%1,539

Taken alongside

1
Acetaminophen22.8%19,212
2
Ondansetron15.1%12,744
3
Aspirin13.2%11,152
4
Ergocalciferol13.2%11,130
5
Omeprazole13.0%10,981
6
Levothyroxine-sodium11.1%9,368
7
Furosemide10.1%8,550
8
Pantoprazole-sodium10.1%8,542
9
Dexamethasone9.7%8,177
10
Albuterol8.7%7,327
11
Atorvastatin-calcium8.5%7,140
12
Amlodipine8.3%7,018
13
Gabapentin8.1%6,876
14
Metoprolol7.7%6,537
15
Potassium-chloride7.4%6,213

Co-occurrence in adverse event reports does not establish a drug interaction. Patients often take multiple medications, and these lists reflect prescribing patterns rather than causal relationships. Consult a healthcare provider about potential drug interactions.

Who reports loperamide side effects

55.1% of loperamide adverse event reports involve female patients and 36.5% involve male patients. The largest age group is elderly at 51%. These figures reflect who reports side effects, not underlying risk.

Sex

Female55.1%
Male36.5%
Unknown8.4%

Age group

< 20.3%
2–111.0%
12–171.1%
18–6446.5%
65+51.1%

What is loperamide used for

Conditions and purposes for which patients were taking loperamide when the adverse event was reported.

Abdominal DiscomfortAbdominal DistensionAbdominal PainAbdominal Pain UpperAbdominal Wall HaematomaAbdominal Wall InfectionAbnormal FaecesAccidentAccidental Drug Intake By ChildAccidental ExposureAccidental Exposure To ProductAccidental Exposure To Product By ChildAccidental OverdoseAcneAdenocarcinoma Gastric

Showing 15 of 736 indications

Loperamide brand names and reporting trend

Loperamide is sold under the brand name Imodium.

Brand names

Imodium732

Quarterly reports (20042025)

20052010201520202025

An upward trend reflects increased FAERS reporting overall, not necessarily increased risk.

Taking loperamide with another medication?

Ask OpenClaim about your specific drug combination. Get a sourced report using FDA data, drug labels, and medical literature.