85/100 · Critical
Manufactured by Allegiant Health
Acetaminophen 500mg: High Serious Reaction Rate and Diverse Safety Concerns
734,137 FDA adverse event reports analyzed
Last updated: 2026-05-12
ACETAMINOPHEN 500MG is a medication tracked in the FDA Adverse Event Reporting System (FAERS), manufactured by Allegiant Health. Based on analysis of 734,137 FDA adverse event reports, ACETAMINOPHEN 500MG has a safety score of 85 out of 100. This score indicates a relatively favorable safety profile, with fewer or less severe adverse events compared to many other tracked medications. The most commonly reported adverse reactions for ACETAMINOPHEN 500MG include OFF LABEL USE, FATIGUE, DRUG INEFFECTIVE, PAIN, NAUSEA. This page provides a comprehensive breakdown of reported side effects, safety signals, patient demographics, and AI-powered safety analysis for ACETAMINOPHEN 500MG.
Acetaminophen 500mg has a safety concern score of 85 out of 100, placing it in the high concern category based on analysis of FDA adverse event data. The FDA has received approximately 734,137 adverse event reports for this medication, which is primarily manufactured by Allegiant Health.
The most commonly reported adverse events include Off Label Use, Fatigue, Drug Ineffective. Of classified reports, 87.3% were designated as serious by the FDA, meaning they involved hospitalization, disability, or other significant medical outcomes. The majority of reactions are non-serious, but the serious reaction rate is high at 87.3%.
Pain and gastrointestinal issues are the most common reactions, but serious conditions like liver enzyme increase and kidney injury also occur. Overdose and intentional product use issues are significant safety concerns, indicating misuse potential.
Patients taking Acetaminophen 500mg should monitor for the commonly reported side effects and contact their healthcare provider if they experience any unusual symptoms. Acetaminophen can cause liver toxicity, especially with overdose. It is contraindicated in patients with liver disease or those at risk of liver damage. This analysis is based on voluntary FDA adverse event reports and should not replace professional medical advice.
Acetaminophen 500mg received a safety concern score of 85/100 (high concern). This is based on a 87.3% serious event ratio across 239,395 classified reports. The score accounts for 734,137 total adverse event reports and 100 distinct reaction types. This high score reflects a significant proportion of serious adverse events in the reporting data.
Adverse event reports by sex: Female: 130,850, Male: 78,943, Unknown: 510. The most frequently reported age groups are age 44 (3,732 reports), age 65 (3,473 reports), age 43 (3,416 reports). These demographics reflect reporting patterns and may not represent the full patient population.
Out of 239,395 classified reports for ACETAMINOPHEN 500MG:
The FDA classifies an adverse event as “serious” if it results in death, hospitalization, disability, congenital anomaly, or requires intervention to prevent permanent damage.
Demographics reflect voluntary FDA adverse event reporting patterns and may not represent the full patient population.
Acetaminophen can cause liver toxicity, especially with overdose. It is contraindicated in patients with liver disease or those at risk of liver damage.
If you are taking Acetaminophen 500mg, here are important things to know. The most commonly reported side effects include off label use, fatigue, drug ineffective, pain, nausea. While many of these may be mild and temporary, you should contact your healthcare provider if any symptoms are severe or persistent. Always follow the recommended dosage and do not exceed the maximum daily limit to avoid liver damage. Be cautious when using acetaminophen with other medications that also contain acetaminophen to avoid accidental overdose. If you experience a serious adverse reaction, seek emergency medical attention immediately or call 911. You can report side effects to the FDA's MedWatch program at 1-800-FDA-1088.
The FDA continues to monitor acetaminophen safety, particularly for serious adverse events and misuse. Regular updates and safety communications are issued.
The FDA has received approximately 734,137 adverse event reports associated with Acetaminophen 500mg. These reports come from healthcare professionals, consumers, and manufacturers through the FDA Adverse Event Reporting System (FAERS). Note that the number of reports does not directly indicate the frequency of side effects, as adverse events are voluntarily reported and may be underrepresented.
The most frequently reported adverse events for Acetaminophen 500mg include Off Label Use, Fatigue, Drug Ineffective, Pain, Nausea. By volume, the top reported reactions are: Off Label Use (21,662 reports), Fatigue (19,932 reports), Drug Ineffective (17,780 reports). These figures reflect FDA adverse event reports and may not represent the true incidence rate of these side effects in all patients taking Acetaminophen 500mg.
Out of 239,395 classified reports, 209,100 (87.3%) were classified as serious and 30,295 as non-serious. The FDA classifies an event as "serious" if it results in death, hospitalization, disability, or other medically significant outcomes. A higher serious-event ratio warrants closer attention but does not necessarily mean the drug is unsafe.
Adverse event reports for Acetaminophen 500mg break down by patient sex as follows: Female: 130,850, Male: 78,943, Unknown: 510. This distribution reflects reporting patterns rather than actual risk differences between groups. Reporting rates can be influenced by prescribing patterns, disease demographics, and reporting behavior.
The most frequently reported age groups for Acetaminophen 500mg adverse events are: age 44: 3,732 reports, age 65: 3,473 reports, age 43: 3,416 reports, age 66: 3,409 reports, age 72: 3,199 reports. Age-related reporting patterns can reflect both the demographics of the patient population and potential age-related susceptibility to certain side effects.
The primary manufacturer associated with Acetaminophen 500mg adverse event reports is Allegiant Health. Multiple manufacturers may produce generic versions of this drug. The manufacturer listed reflects the most frequently reported brand in FDA adverse event data.
Beyond the most common reactions, other reported adverse events for Acetaminophen 500mg include: Headache, Toxicity To Various Agents, Dyspnoea, Arthralgia, Pyrexia. Less common side effects can still be clinically significant. Patients should report any unusual symptoms to their healthcare provider.
You can report adverse events from Acetaminophen 500mg to the FDA through their MedWatch program at www.fda.gov/medwatch, by calling 1-800-FDA-1088, or by completing Form FDA 3500. Healthcare professionals, consumers, and manufacturers can all submit reports. Reporting helps the FDA monitor drug safety after approval.
Acetaminophen 500mg has a safety concern score of 85 out of 100 (high concern). This score is calculated from the ratio of serious to non-serious adverse events, the diversity of reported reactions, and the overall volume of reports relative to usage. The majority of reactions are non-serious, but the serious reaction rate is high at 87.3%.
Key safety signals identified in Acetaminophen 500mg's adverse event data include: High rate of serious reactions (87.3%). Liver enzyme increase and kidney injury reported. Overdose and intentional misuse are common. Diverse range of reactions including respiratory, musculoskeletal, and neurological issues. These signals are derived from patterns in FDA reports and should be discussed with a healthcare provider for personalized assessment.
Acetaminophen can cause liver toxicity, especially with overdose. It is contraindicated in patients with liver disease or those at risk of liver damage. Always inform your healthcare provider about all medications, supplements, and over-the-counter drugs you are taking before starting Acetaminophen 500mg.
Always follow the recommended dosage and do not exceed the maximum daily limit to avoid liver damage. Be cautious when using acetaminophen with other medications that also contain acetaminophen to avoid accidental overdose.
Acetaminophen 500mg has 734,137 adverse event reports on file with the FDA. Pain and gastrointestinal issues are the most common reactions, but serious conditions like liver enzyme increase and kidney injury also occur. The volume of reports for Acetaminophen 500mg reflects both the drug's usage level and the vigilance of the reporting community.
The FDA continues to monitor acetaminophen safety, particularly for serious adverse events and misuse. Regular updates and safety communications are issued. For the most current regulatory information, check the FDA's drug labeling database or consult your pharmacist.
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