55/100 · Moderate
Manufactured by ENDO USA, Inc.
Levothyroxine Sodium Anhydrous Adverse Events: Common Mild Reactions with Some Serious Concerns
215,491 FDA adverse event reports analyzed
Last updated: 2026-05-12
LEVOTHYROXINE SODIUM ANHYDROUS is a medication tracked in the FDA Adverse Event Reporting System (FAERS), manufactured by ENDO USA, Inc.. Based on analysis of 215,491 FDA adverse event reports, LEVOTHYROXINE SODIUM ANHYDROUS has a safety score of 55 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 LEVOTHYROXINE SODIUM ANHYDROUS include FATIGUE, NAUSEA, DIARRHOEA, HEADACHE, DYSPNOEA. This page provides a comprehensive breakdown of reported side effects, safety signals, patient demographics, and AI-powered safety analysis for LEVOTHYROXINE SODIUM ANHYDROUS.
Levothyroxine Sodium Anhydrous has a safety concern score of 55 out of 100, placing it in the elevated concern category based on analysis of FDA adverse event data. The FDA has received approximately 215,491 adverse event reports for this medication, which is primarily manufactured by Endo Usa, Inc..
The most commonly reported adverse events include Fatigue, Nausea, Diarrhoea. Of classified reports, 70.0% were designated as serious by the FDA, meaning they involved hospitalization, disability, or other significant medical outcomes. Most common reactions include fatigue, nausea, and diarrhea, which are generally mild.
Serious adverse events such as pneumonia, heart failure, and death are reported but less frequently. Drug interactions and off-label use are significant safety signals. Age distribution shows a higher number of reports in older adults, with serious events more prevalent in this group.
Patients taking Levothyroxine Sodium Anhydrous should monitor for the commonly reported side effects and contact their healthcare provider if they experience any unusual symptoms. Levothyroxine can interact with other medications and should not be used off-label without medical supervision. Patients should inform their healthcare provider of all medications they are taking. This analysis is based on voluntary FDA adverse event reports and should not replace professional medical advice.
Levothyroxine Sodium Anhydrous received a safety concern score of 55/100 (elevated concern). This is based on a 70.0% serious event ratio across 95,247 classified reports. The score accounts for 215,491 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: 67,505, Male: 21,426, Unknown: 88. The most frequently reported age groups are age 77 (1,879 reports), age 65 (1,762 reports), age 76 (1,580 reports). These demographics reflect reporting patterns and may not represent the full patient population.
Out of 95,247 classified reports for LEVOTHYROXINE SODIUM ANHYDROUS:
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.
Levothyroxine can interact with other medications and should not be used off-label without medical supervision. Patients should inform their healthcare provider of all medications they are taking.
If you are taking Levothyroxine Sodium Anhydrous, here are important things to know. The most commonly reported side effects include fatigue, nausea, diarrhoea, headache, dyspnoea. While many of these may be mild and temporary, you should contact your healthcare provider if any symptoms are severe or persistent. Always inform your healthcare provider about all medications you are taking to avoid potential drug interactions. Do not use Levothyroxine for conditions for which it is not prescribed. 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 Levothyroxine Sodium Anhydrous for safety, particularly in older adults and those with pre-existing heart conditions.
The FDA has received approximately 215,491 adverse event reports associated with Levothyroxine Sodium Anhydrous. 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 Levothyroxine Sodium Anhydrous include Fatigue, Nausea, Diarrhoea, Headache, Dyspnoea. By volume, the top reported reactions are: Fatigue (7,716 reports), Nausea (6,793 reports), Diarrhoea (6,107 reports). These figures reflect FDA adverse event reports and may not represent the true incidence rate of these side effects in all patients taking Levothyroxine Sodium Anhydrous.
Out of 95,247 classified reports, 66,670 (70.0%) were classified as serious and 28,577 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 Levothyroxine Sodium Anhydrous break down by patient sex as follows: Female: 67,505, Male: 21,426, Unknown: 88. 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 Levothyroxine Sodium Anhydrous adverse events are: age 77: 1,879 reports, age 65: 1,762 reports, age 76: 1,580 reports, age 74: 1,568 reports, age 78: 1,567 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 Levothyroxine Sodium Anhydrous adverse event reports is Endo Usa, 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 Levothyroxine Sodium Anhydrous include: Drug Ineffective, Pain, Dizziness, Vomiting, Asthenia. 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 Levothyroxine Sodium Anhydrous 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.
Levothyroxine Sodium Anhydrous has a safety concern score of 55 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 fatigue, nausea, and diarrhea, which are generally mild.
Key safety signals identified in Levothyroxine Sodium Anhydrous's adverse event data include: Pneumonia and heart failure are key serious safety signals.. Drug interactions and off-label use are critical safety signals.. A significant number of reports involve serious adverse events, particularly in older adults.. These signals are derived from patterns in FDA reports and should be discussed with a healthcare provider for personalized assessment.
Levothyroxine can interact with other medications and should not be used off-label without medical supervision. Patients should inform their healthcare provider of all medications they are taking. Always inform your healthcare provider about all medications, supplements, and over-the-counter drugs you are taking before starting Levothyroxine Sodium Anhydrous.
Always inform your healthcare provider about all medications you are taking to avoid potential drug interactions. Do not use Levothyroxine for conditions for which it is not prescribed.
Levothyroxine Sodium Anhydrous has 215,491 adverse event reports on file with the FDA. Serious adverse events such as pneumonia, heart failure, and death are reported but less frequently. The volume of reports for Levothyroxine Sodium Anhydrous reflects both the drug's usage level and the vigilance of the reporting community.
The FDA continues to monitor Levothyroxine Sodium Anhydrous for safety, particularly in older adults and those with pre-existing heart conditions. For the most current regulatory information, check the FDA's drug labeling database or consult your pharmacist.
Explore other medications manufactured by ENDO USA, Inc. and compare their safety profiles:
The following drugs share commonly reported adverse reactions with LEVOTHYROXINE SODIUM ANHYDROUS:
Drugs related to LEVOTHYROXINE SODIUM ANHYDROUS based on therapeutic use, drug class, or shared indications: