Hydroxychloroquine Sulfate
According to the FDA label: Hydroxychloroquine sulfate tablets are an antimalarial and antirheumatic indicated for the: Treatment of uncomplicated malaria due to Plasmodium falciparum, Plasmodium malariae, Plasmodium ovale, and Plasmodium vivax in adult and pediatric patients. ( 1.1 ) Prophylaxis of malaria in geographic areas where chloroquine resistance is not reported in adult and pediatric patients. ( 1.1 ) Treatment of rheumatoid arthritis in adults. ( 1.2 ) Treatment of systemic lupus erythematosus in adults.
39,136 adverse event reports submitted to the FDA (2004–2026)
Top Reported Adverse Events
The most frequently reported events in association with Hydroxychloroquine Sulfate in the FAERS database. These are events reported by patients taking this medication, not necessarily caused by it. A single report may include multiple events.
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Drug Ineffective 18,095 reports
A report that the medication did not work as expected for the person taking it. This is a reporting category, not a sign the drug is defective. It simply means someone felt it was not helping their condition.
Full definition in the glossary →Rheumatoid Arthritis 13,674 reports
An autoimmune condition where the immune system attacks the joints, causing pain and swelling. It often appears in reports because it is a condition being treated, not always a reaction.
Full definition in the glossary →Pain 10,809 reports
A general report of physical discomfort, used when no more specific location is given.
Full definition in the glossary →Fatigue 9,379 reports
Extreme tiredness or lack of energy that does not improve with rest.
Full definition in the glossary → See all drugs reporting this event →Drug Intolerance 9,240 reports
A report that the person could not tolerate a medication, often due to uncomfortable effects.
Full definition in the glossary →Off Label Use 8,457 reports
Using a medication for a condition or in a way that the FDA has not officially approved. This is common and often legal, and a report of it does not mean something went wrong. Doctors sometimes prescribe drugs off label based on their judgment.
Full definition in the glossary →Joint Swelling 8,397 reports
Swelling in or around a joint.
Full definition in the glossary →Arthralgia 8,376 reports
Contraindicated Product Administered 8,075 reports
A report that a medication was given in a situation where it was not recommended, for example when another condition made it unsuitable. This is a reporting category describing what happened, not a measure of harm by itself.
Full definition in the glossary →Alopecia 7,711 reports
Abdominal Discomfort 7,694 reports
A general unease or mild pain in the belly area.
Full definition in the glossary →Rash 7,617 reports
An area of irritated, red, or bumpy skin.
Full definition in the glossary → See all drugs reporting this event →Arthropathy 7,168 reports
Any disease or disorder of a joint.
Full definition in the glossary →Systemic Lupus Erythematosus 7,149 reports
An autoimmune condition, often called lupus, where the immune system attacks the body's own tissues, affecting joints, skin, and organs. It often appears in reports because it is a condition being treated, not always a reaction.
Full definition in the glossary →Synovitis 6,892 reports
Inflammation of the lining of a joint, causing swelling and pain.
Full definition in the glossary →
Ranked by frequency of reports, not severity. The most-reported event is not necessarily the most dangerous or the most common in patients taking this drug.
Who Is Reporting
Demographics of patients in FAERS reports that included this information. Not all reports include patient demographics.
By Sex
View reporter sex data as a table
| Sex | Reports |
|---|---|
| Female | 27,915 |
| Male | 4,493 |
| Unknown | 11 |
By Age Group
View age group data as a table
| Age group | Reports |
|---|---|
| 0-17 | 496 |
| 18-34 | 1,453 |
| 35-49 | 7,131 |
| 50-64 | 8,057 |
| 65-74 | 3,370 |
| 75+ | 1,522 |
This shows who filed reports, reflecting who takes this drug and who tends to report, not who is at greatest risk.
Reported Outcomes
Outcomes recorded in FAERS reports that included Hydroxychloroquine Sulfate. A single report may involve multiple reactions, each with a different outcome. These categories are defined by FDA reporting guidelines, not by PillSignal.
View outcome data as a table
| Outcome | Reports |
|---|---|
| Other Serious | 29,916 |
| Hospitalization | 10,939 |
| Disability | 6,249 |
| Non-Serious | 4,671 |
| Life-Threatening | 4,347 |
| Death | 4,145 |
Serious outcomes are far more likely to be reported than mild ones, so this overstates how often outcomes are serious. A recorded death does not mean the drug caused it.
Report Volume Over Time
Number of FAERS reports received per quarter for Hydroxychloroquine Sulfate. Changes in volume may reflect shifts in prescribing rates, media attention, or reporting behavior, not changes in the medication's safety profile.
View report trend as a table
| Year | Reports |
|---|---|
| 2004 | 173 |
| 2005 | 231 |
| 2006 | 174 |
| 2007 | 243 |
| 2008 | 402 |
| 2009 | 368 |
| 2010 | 660 |
| 2011 | 421 |
| 2012 | 724 |
| 2013 | 208 |
| 2014 | 143 |
| 2015 | 371 |
| 2016 | 902 |
| 2017 | 1,044 |
| 2018 | 1,598 |
| 2019 | 3,279 |
| 2020 | 7,825 |
| 2021 | 5,382 |
| 2022 | 4,543 |
| 2023 | 2,946 |
| 2024 | 3,566 |
| 2025 | 3,367 |
| 2026 (partial) | 566 |
The steep increase around 2004 reflects the FDA's move to electronic submission, not a change in this drug's safety. Trends track reporting volume, not risk.
Medications commonly reported with Hydroxychloroquine Sulfate
In FDA adverse event reports that mention Hydroxychloroquine Sulfate, these medications appeared most often in the same report.
- Adalimumab (19,228 reports)
- Prednisone (18,923 reports)
- Abatacept (18,068 reports)
- Tocilizumab (17,725 reports)
- Sulfasalazine (17,351 reports)
This reflects co-occurrence in submitted reports, not evidence of drug interaction or combined risk. People often report several medications taken for the same condition or for unrelated reasons. Talk to a doctor or pharmacist about your specific medications.
Related Drugs
Other medications with similar adverse event profiles in FDA FAERS reports.
Data Source
This data is sourced from the FDA's Adverse Event Monitoring System (AEMS), formerly FAERS, via the OpenFDA API. PillSignal is not affiliated with the FDA.
View this data on the FDA website →Data last updated: June 2026