85/100 · Critical
Manufactured by Merck Sharp & Dohme LLC
High Safety Concerns with Temozolomide, Particularly for Serious Adverse Events
38,373 FDA adverse event reports analyzed
Last updated: 2026-05-12
TEMOZOLOMIDE is a medication tracked in the FDA Adverse Event Reporting System (FAERS), manufactured by Merck Sharp & Dohme LLC. Based on analysis of 38,373 FDA adverse event reports, TEMOZOLOMIDE 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 TEMOZOLOMIDE include DISEASE PROGRESSION, DEATH, OFF LABEL USE, THROMBOCYTOPENIA, PRODUCT USE IN UNAPPROVED INDICATION. This page provides a comprehensive breakdown of reported side effects, safety signals, patient demographics, and AI-powered safety analysis for TEMOZOLOMIDE.
Temozolomide 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 38,373 adverse event reports for this medication, which is primarily manufactured by Merck Sharp & Dohme Llc.
The most commonly reported adverse events include Disease Progression, Death, Off Label Use. Of classified reports, 81.0% were designated as serious by the FDA, meaning they involved hospitalization, disability, or other significant medical outcomes. High incidence of serious adverse events such as disease progression and death.
Significant hematological toxicity, including thrombocytopenia and neutropenia. Common gastrointestinal issues like nausea and vomiting.
Patients taking Temozolomide should monitor for the commonly reported side effects and contact their healthcare provider if they experience any unusual symptoms. Temozolomide can cause severe hematological and gastrointestinal side effects, and patients should be monitored closely for these issues. Drug interactions, particularly with other hematological agents, should be carefully managed. This analysis is based on voluntary FDA adverse event reports and should not replace professional medical advice.
Temozolomide received a safety concern score of 85/100 (high concern). This is based on a 81.0% serious event ratio across 20,264 classified reports. The score accounts for 38,373 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: Male: 9,249, Female: 7,868, Unknown: 171. The most frequently reported age groups are age 59 (343 reports), age 67 (323 reports), age 65 (316 reports). These demographics reflect reporting patterns and may not represent the full patient population.
Out of 20,264 classified reports for TEMOZOLOMIDE:
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.
Temozolomide can cause severe hematological and gastrointestinal side effects, and patients should be monitored closely for these issues. Drug interactions, particularly with other hematological agents, should be carefully managed.
If you are taking Temozolomide, here are important things to know. The most commonly reported side effects include disease progression, death, off label use, thrombocytopenia, product use in unapproved indication. While many of these may be mild and temporary, you should contact your healthcare provider if any symptoms are severe or persistent. Monitor patients closely for signs of hematological toxicity and gastrointestinal issues. Be aware of potential drug interactions, especially with other hematological agents. 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.
Regulatory oversight is ongoing, with a focus on monitoring hematological and gastrointestinal toxicity. Healthcare providers should report any adverse events to the FDA.
The FDA has received approximately 38,373 adverse event reports associated with Temozolomide. 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 Temozolomide include Disease Progression, Death, Off Label Use, Thrombocytopenia, Product Use In Unapproved Indication. By volume, the top reported reactions are: Disease Progression (1,849 reports), Death (1,683 reports), Off Label Use (1,640 reports). These figures reflect FDA adverse event reports and may not represent the true incidence rate of these side effects in all patients taking Temozolomide.
Out of 20,264 classified reports, 16,404 (81.0%) were classified as serious and 3,860 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 Temozolomide break down by patient sex as follows: Male: 9,249, Female: 7,868, Unknown: 171. 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 Temozolomide adverse events are: age 59: 343 reports, age 67: 323 reports, age 65: 316 reports, age 66: 316 reports, age 64: 314 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 Temozolomide adverse event reports is Merck Sharp & Dohme 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 Temozolomide include: Nausea, Drug Ineffective, Fatigue, Neutropenia, Vomiting. 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 Temozolomide 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.
Temozolomide 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. High incidence of serious adverse events such as disease progression and death.
Key safety signals identified in Temozolomide's adverse event data include: High number of reports of disease progression and death.. Severe hematological effects including thrombocytopenia and neutropenia.. Frequent gastrointestinal side effects such as nausea and vomiting.. These signals are derived from patterns in FDA reports and should be discussed with a healthcare provider for personalized assessment.
Temozolomide can cause severe hematological and gastrointestinal side effects, and patients should be monitored closely for these issues. Drug interactions, particularly with other hematological agents, should be carefully managed. Always inform your healthcare provider about all medications, supplements, and over-the-counter drugs you are taking before starting Temozolomide.
Monitor patients closely for signs of hematological toxicity and gastrointestinal issues. Be aware of potential drug interactions, especially with other hematological agents.
Temozolomide has 38,373 adverse event reports on file with the FDA. Significant hematological toxicity, including thrombocytopenia and neutropenia. The volume of reports for Temozolomide reflects both the drug's usage level and the vigilance of the reporting community.
Regulatory oversight is ongoing, with a focus on monitoring hematological and gastrointestinal toxicity. Healthcare providers should report any adverse events to the FDA. For the most current regulatory information, check the FDA's drug labeling database or consult your pharmacist.
Explore other medications manufactured by Merck Sharp & Dohme LLC and compare their safety profiles:
The following drugs share commonly reported adverse reactions with TEMOZOLOMIDE:
Drugs related to TEMOZOLOMIDE based on therapeutic use, drug class, or shared indications: