72/100 · Elevated
Manufactured by Mylan Pharmaceuticals Inc.
Valacyclovir Hydrochloride Adverse Events Show High Fatigue and Nausea Rates
115,711 FDA adverse event reports analyzed
Last updated: 2026-05-12
VALACYCLOVIR HYDROCHLORIDE is a medication tracked in the FDA Adverse Event Reporting System (FAERS), manufactured by Mylan Pharmaceuticals Inc.. Based on analysis of 115,711 FDA adverse event reports, VALACYCLOVIR HYDROCHLORIDE has a safety score of 72 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 VALACYCLOVIR HYDROCHLORIDE include FATIGUE, DRUG INEFFECTIVE, NAUSEA, OFF LABEL USE, DIARRHOEA. This page provides a comprehensive breakdown of reported side effects, safety signals, patient demographics, and AI-powered safety analysis for VALACYCLOVIR HYDROCHLORIDE.
Valacyclovir Hydrochloride has a safety concern score of 72 out of 100, placing it in the elevated concern category based on analysis of FDA adverse event data. The FDA has received approximately 115,711 adverse event reports for this medication, which is primarily manufactured by Mylan Pharmaceuticals Inc..
The most commonly reported adverse events include Fatigue, Drug Ineffective, Nausea. Of classified reports, 69.3% were designated as serious by the FDA, meaning they involved hospitalization, disability, or other significant medical outcomes. Fatigue and nausea are the most common adverse reactions reported.
Serious adverse events, such as pneumonia and sepsis, are concerning. Drug interactions and product misuse are reported, warranting caution.
Patients taking Valacyclovir Hydrochloride should monitor for the commonly reported side effects and contact their healthcare provider if they experience any unusual symptoms. Valacyclovir Hydrochloride can interact with other drugs, and misuse has been reported, so it is important to follow prescribed dosages and avoid concurrent use with other antivirals. This analysis is based on voluntary FDA adverse event reports and should not replace professional medical advice.
Valacyclovir Hydrochloride received a safety concern score of 72/100 (elevated concern). This is based on a 69.3% serious event ratio across 67,035 classified reports. The score accounts for 115,711 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: 36,658, Male: 24,406, Unknown: 135. The most frequently reported age groups are age 68 (1,266 reports), age 67 (1,222 reports), age 71 (1,221 reports). These demographics reflect reporting patterns and may not represent the full patient population.
Out of 67,035 classified reports for VALACYCLOVIR 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.
Valacyclovir Hydrochloride can interact with other drugs, and misuse has been reported, so it is important to follow prescribed dosages and avoid concurrent use with other antivirals.
If you are taking Valacyclovir Hydrochloride, here are important things to know. The most commonly reported side effects include fatigue, drug ineffective, nausea, off label use, diarrhoea. 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 avoid self-medicating or using the drug off-label. Report any adverse reactions to your healthcare provider and the FDA's MedWatch program. 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 monitors adverse events to ensure public safety. Regular monitoring by healthcare providers and patients is crucial to identify and manage potential risks.
The FDA has received approximately 115,711 adverse event reports associated with Valacyclovir 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 Valacyclovir Hydrochloride include Fatigue, Drug Ineffective, Nausea, Off Label Use, Diarrhoea. By volume, the top reported reactions are: Fatigue (4,126 reports), Drug Ineffective (3,829 reports), Nausea (3,813 reports). These figures reflect FDA adverse event reports and may not represent the true incidence rate of these side effects in all patients taking Valacyclovir Hydrochloride.
Out of 67,035 classified reports, 46,455 (69.3%) were classified as serious and 20,580 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 Valacyclovir Hydrochloride break down by patient sex as follows: Female: 36,658, Male: 24,406, Unknown: 135. 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 Valacyclovir Hydrochloride adverse events are: age 68: 1,266 reports, age 67: 1,222 reports, age 71: 1,221 reports, age 72: 1,147 reports, age 62: 1,139 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 Valacyclovir Hydrochloride adverse event reports is Mylan Pharmaceuticals 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 Valacyclovir Hydrochloride include: Headache, Pyrexia, Pain, Pneumonia, Rash. 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 Valacyclovir 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.
Valacyclovir Hydrochloride has a safety concern score of 72 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. Fatigue and nausea are the most common adverse reactions reported.
Key safety signals identified in Valacyclovir Hydrochloride's adverse event data include: Frequent reports of fatigue and nausea indicate a common side effect profile.. Serious events like pneumonia and sepsis highlight potential severe risks.. Multiple reports of drug interactions and misuse suggest caution is needed.. These signals are derived from patterns in FDA reports and should be discussed with a healthcare provider for personalized assessment.
Valacyclovir Hydrochloride can interact with other drugs, and misuse has been reported, so it is important to follow prescribed dosages and avoid concurrent use with other antivirals. Always inform your healthcare provider about all medications, supplements, and over-the-counter drugs you are taking before starting Valacyclovir Hydrochloride.
Follow prescribed dosages and avoid self-medicating or using the drug off-label. Report any adverse reactions to your healthcare provider and the FDA's MedWatch program.
Valacyclovir Hydrochloride has 115,711 adverse event reports on file with the FDA. Serious adverse events, such as pneumonia and sepsis, are concerning. The volume of reports for Valacyclovir Hydrochloride reflects both the drug's usage level and the vigilance of the reporting community.
The FDA monitors adverse events to ensure public safety. Regular monitoring by healthcare providers and patients is crucial to identify and manage potential risks. For the most current regulatory information, check the FDA's drug labeling database or consult your pharmacist.
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