65/100 · Elevated
Manufactured by AAA Pharmaceutical, Inc.
Diphenhydramine Adverse Events: Common Mild Reactions with Serious Incidents
181,665 FDA adverse event reports analyzed
Last updated: 2026-05-12
DIPHENHYDRAMINE is a medication tracked in the FDA Adverse Event Reporting System (FAERS), manufactured by AAA Pharmaceutical, Inc.. Based on analysis of 181,665 FDA adverse event reports, DIPHENHYDRAMINE has a safety score of 65 out of 100. This moderate score indicates a notable volume of adverse event reports that patients and providers should be aware of. The most commonly reported adverse reactions for DIPHENHYDRAMINE include OFF LABEL USE, HEADACHE, FATIGUE, NAUSEA, PAIN. This page provides a comprehensive breakdown of reported side effects, safety signals, patient demographics, and AI-powered safety analysis for DIPHENHYDRAMINE.
Diphenhydramine has a safety concern score of 65 out of 100, placing it in the elevated concern category based on analysis of FDA adverse event data. The FDA has received approximately 181,665 adverse event reports for this medication, which is primarily manufactured by Aaa Pharmaceutical, Inc..
The most commonly reported adverse events include Off Label Use, Headache, Fatigue. Of classified reports, 76.0% were designated as serious by the FDA, meaning they involved hospitalization, disability, or other significant medical outcomes. Most common reactions include headache, fatigue, and nausea, which are generally mild.
Serious adverse events, such as pneumonia, heart arrest, and death, are reported but less frequent. Drug interactions and misuse are significant concerns, particularly with intentional misuse and overdose. The majority of reactions are non-serious, but the presence of serious events warrants ongoing monitoring.
Patients taking Diphenhydramine should monitor for the commonly reported side effects and contact their healthcare provider if they experience any unusual symptoms. Diphenhydramine can interact with other medications, potentially leading to increased side effects or reduced efficacy. Misuse, including intentional overdose, is a significant risk. This analysis is based on voluntary FDA adverse event reports and should not replace professional medical advice.
Diphenhydramine received a safety concern score of 65/100 (elevated concern). This is based on a 76.0% serious event ratio across 60,510 classified reports. The score accounts for 181,665 total adverse event reports and 100 distinct reaction types. This elevated score indicates a notable proportion of serious adverse events and warrants careful monitoring.
Adverse event reports by sex: Female: 33,647, Male: 18,719, Unknown: 94. The most frequently reported age groups are age 58 (922 reports), age 57 (804 reports), age 50 (790 reports). These demographics reflect reporting patterns and may not represent the full patient population.
Out of 60,510 classified reports for DIPHENHYDRAMINE:
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.
Diphenhydramine can interact with other medications, potentially leading to increased side effects or reduced efficacy. Misuse, including intentional overdose, is a significant risk.
If you are taking Diphenhydramine, here are important things to know. The most commonly reported side effects include off label use, headache, fatigue, nausea, pain. 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 prescribed dosage and duration of use. Report any unusual symptoms or side effects to your healthcare provider immediately. 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 Diphenhydramine for safety, particularly in elderly populations and those with pre-existing conditions. Regularly review medication instructions and avoid self-medicating without a prescription.
The FDA has received approximately 181,665 adverse event reports associated with Diphenhydramine. 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 Diphenhydramine include Off Label Use, Headache, Fatigue, Nausea, Pain. By volume, the top reported reactions are: Off Label Use (7,770 reports), Headache (5,139 reports), Fatigue (5,076 reports). These figures reflect FDA adverse event reports and may not represent the true incidence rate of these side effects in all patients taking Diphenhydramine.
Out of 60,510 classified reports, 46,005 (76.0%) were classified as serious and 14,505 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 Diphenhydramine break down by patient sex as follows: Female: 33,647, Male: 18,719, Unknown: 94. 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 Diphenhydramine adverse events are: age 58: 922 reports, age 57: 804 reports, age 50: 790 reports, age 61: 788 reports, age 65: 772 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 Diphenhydramine adverse event reports is Aaa Pharmaceutical, Inc.. 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 Diphenhydramine include: Drug Ineffective, Sinusitis, Toxicity To Various Agents, Dyspnoea, 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 Diphenhydramine 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.
Diphenhydramine has a safety concern score of 65 out of 100 (elevated 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. Most common reactions include headache, fatigue, and nausea, which are generally mild.
Key safety signals identified in Diphenhydramine's adverse event data include: Intentional misuse and overdose are key safety signals.. Heart-related issues, including arrest, are serious safety concerns.. Pneumonia and other infections are notable adverse events.. Drug ineffectiveness and inappropriate schedule of administration are frequent issues.. These signals are derived from patterns in FDA reports and should be discussed with a healthcare provider for personalized assessment.
Diphenhydramine can interact with other medications, potentially leading to increased side effects or reduced efficacy. Misuse, including intentional overdose, is a significant risk. Always inform your healthcare provider about all medications, supplements, and over-the-counter drugs you are taking before starting Diphenhydramine.
Always follow the prescribed dosage and duration of use. Report any unusual symptoms or side effects to your healthcare provider immediately.
Diphenhydramine has 181,665 adverse event reports on file with the FDA. Serious adverse events, such as pneumonia, heart arrest, and death, are reported but less frequent. The volume of reports for Diphenhydramine reflects both the drug's usage level and the vigilance of the reporting community.
The FDA continues to monitor Diphenhydramine for safety, particularly in elderly populations and those with pre-existing conditions. Regularly review medication instructions and avoid self-medicating without a prescription. For the most current regulatory information, check the FDA's drug labeling database or consult your pharmacist.
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