78/100 · Elevated
Manufactured by Kenvue Brands LLC
Diphenhydramine Hydrochloride Adverse Events Show High Seriousness and Diverse Reactions
482,745 FDA adverse event reports analyzed
Last updated: 2026-05-12
DIPHENHYDRAMINE HYDROCHLORIDE is a medication tracked in the FDA Adverse Event Reporting System (FAERS), manufactured by Kenvue Brands LLC. Based on analysis of 482,745 FDA adverse event reports, DIPHENHYDRAMINE HYDROCHLORIDE has a safety score of 78 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 DIPHENHYDRAMINE HYDROCHLORIDE include OFF LABEL USE, FATIGUE, NAUSEA, HEADACHE, PAIN. This page provides a comprehensive breakdown of reported side effects, safety signals, patient demographics, and AI-powered safety analysis for DIPHENHYDRAMINE HYDROCHLORIDE.
Diphenhydramine Hydrochloride has a safety concern score of 78 out of 100, placing it in the high concern category based on analysis of FDA adverse event data. The FDA has received approximately 482,745 adverse event reports for this medication, which is primarily manufactured by Kenvue Brands Llc.
The most commonly reported adverse events include Off Label Use, Fatigue, Nausea. Of classified reports, 71.2% were designated as serious by the FDA, meaning they involved hospitalization, disability, or other significant medical outcomes. The majority of adverse events are serious, with 71.2% of reports being classified as such.
A wide range of reactions are reported, including respiratory, cardiovascular, and neurological issues. The drug is frequently reported to be ineffective, with 11,066 cases noted.
Patients taking Diphenhydramine Hydrochloride should monitor for the commonly reported side effects and contact their healthcare provider if they experience any unusual symptoms. Diphenhydramine Hydrochloride can cause serious adverse events such as respiratory issues, cardiovascular problems, and neurological symptoms. It is important to follow prescribed dosages and use as directed. This analysis is based on voluntary FDA adverse event reports and should not replace professional medical advice.
Diphenhydramine Hydrochloride received a safety concern score of 78/100 (high concern). This is based on a 71.2% serious event ratio across 159,192 classified reports. The score accounts for 482,745 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: 91,648, Male: 46,300, Unknown: 292. The most frequently reported age groups are age 58 (2,286 reports), age 59 (2,174 reports), age 65 (2,127 reports). These demographics reflect reporting patterns and may not represent the full patient population.
Out of 159,192 classified reports for DIPHENHYDRAMINE HYDROCHLORIDE:
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 Hydrochloride can cause serious adverse events such as respiratory issues, cardiovascular problems, and neurological symptoms. It is important to follow prescribed dosages and use as directed.
If you are taking Diphenhydramine Hydrochloride, here are important things to know. The most commonly reported side effects include off label use, fatigue, nausea, headache, pain. While many of these may be mild and temporary, you should contact your healthcare provider if any symptoms are severe or persistent. Follow prescribed dosages and use as directed to minimize the risk of adverse events. Be aware of potential serious reactions and seek medical attention if any severe symptoms occur. 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 Hydrochloride for safety, particularly for serious adverse events. Healthcare providers should be vigilant in monitoring patients for any signs of severe reactions.
The FDA has received approximately 482,745 adverse event reports associated with Diphenhydramine Hydrochloride. 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 Hydrochloride include Off Label Use, Fatigue, Nausea, Headache, Pain. By volume, the top reported reactions are: Off Label Use (17,231 reports), Fatigue (15,369 reports), Nausea (13,733 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 Hydrochloride.
Out of 159,192 classified reports, 113,370 (71.2%) were classified as serious and 45,822 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 Hydrochloride break down by patient sex as follows: Female: 91,648, Male: 46,300, Unknown: 292. 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 Hydrochloride adverse events are: age 58: 2,286 reports, age 59: 2,174 reports, age 65: 2,127 reports, age 61: 2,115 reports, age 57: 2,081 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 Hydrochloride adverse event reports is Kenvue Brands Llc. 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 Hydrochloride include: Drug Ineffective, Dyspnoea, Pruritus, Infusion Related Reaction, Arthralgia. 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 Hydrochloride 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 Hydrochloride has a safety concern score of 78 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 adverse events are serious, with 71.2% of reports being classified as such.
Key safety signals identified in Diphenhydramine Hydrochloride's adverse event data include: High percentage of serious adverse events (71.2%). Diverse range of reactions including respiratory, cardiovascular, and neurological issues. Frequent reports of drug ineffectiveness. These signals are derived from patterns in FDA reports and should be discussed with a healthcare provider for personalized assessment.
Diphenhydramine Hydrochloride can cause serious adverse events such as respiratory issues, cardiovascular problems, and neurological symptoms. It is important to follow prescribed dosages and use as directed. Always inform your healthcare provider about all medications, supplements, and over-the-counter drugs you are taking before starting Diphenhydramine Hydrochloride.
Follow prescribed dosages and use as directed to minimize the risk of adverse events. Be aware of potential serious reactions and seek medical attention if any severe symptoms occur.
Diphenhydramine Hydrochloride has 482,745 adverse event reports on file with the FDA. A wide range of reactions are reported, including respiratory, cardiovascular, and neurological issues. The volume of reports for Diphenhydramine Hydrochloride reflects both the drug's usage level and the vigilance of the reporting community.
The FDA continues to monitor Diphenhydramine Hydrochloride for safety, particularly for serious adverse events. Healthcare providers should be vigilant in monitoring patients for any signs of severe reactions. For the most current regulatory information, check the FDA's drug labeling database or consult your pharmacist.
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