What is Hydroxychloroquine Used For?

Published April 26th, 2020 by Chris Riley
Fact Checked by
Chris Riley

Currently, a few existing drugs are being investigated for their potential as therapeutic agents in the treatment of the pandemic, COVID-19. As of now, there are no drugs that have been proven to work for the illness that is caused by the SARS-CoV-2 virus. As finding an immediate solution to the pandemic is urgent, research is being conducted around the world to find an existing drug that could be recycled for the purpose of treating COVID-19. One such drug that has made major headlines is hydroxychloroquine. The Food and Drug Administration (FDA) recently approved hydroxychloroquine for “Emergency Use Authorization’, meaning that it can be used to treat patients who are hospitalized and do not have the option of enrolling in a clinical trial to test whether the drug is beneficial in treating COVID-19. Ordinarily, a drug must undergo rigorous clinical trials before it is approved for therapeutic use to treat a specific disease. Given the lack of option to treat COVID-19, Emergency Use Authorization gives doctors the ability to treat patients who are hospitalized due to the illness even though the benefits are still unknown.  

One common misconception about hydroxychloroquine is that it is a new drug that we do not know anything about. While many people may not have heard about this drug before, it is no new player in the medical field. What is Hydroxychloroquine? Hydroxychloroquine belongs to group of drugs in the 4-aminiquinolone family that is known for its anti-malarial properties. Its predecessor drugs, chloroquine and quinolone, also belong to this family. What is Hydroxychloroquine used for? Quinolone has been in use since the 1600s, and hydroxychloroquine has been FDA-approved since the 1940s. Today, a lot is known about how hydroxychloroquine works and behaves in the body, and how safe it is as a therapeutic agent. Importantly, although hydroxychloroquine started out as a drug to treat malaria, it was quickly recognized for its potent ability to reduce inflammatory responses in the body, making it an attractive candidate for the treatment of autoimmune diseases in which widespread inflammation is often a problem. 

While we do know that it is effective and safe for certain medical problems, hydroxychloroquine must be only be taken under the strict supervision of a physician, and with a valid prescription, as taking this drug in the wrong way can be harmful. One of the major drawbacks of using high doses of this drug is its ability to cause retinal toxicity. Therefore, even though hydroxychloroquine may seem like an attractive choice for the treatment of COVID-19, it is essential not to self-medicate without a prescription until clinical trials have proven that it is effective. 

Here are the major FDA-approved uses of hydroxychloroquine and how it works for the following indications: 


Hydroxychloroquine is one of the major drugs used to prevent and treat malaria around the world. Malaria is a mosquito-transmitted disease caused by the Plasmodium parasites that first infects liver cells in the body and then travels to red blood cells to multiply there. Although the threat of contracting malaria is not high in the United States, malaria remains a major health concern in some areas of the world like sub-saharan Africa and some regions of Asia. According to the World Health Organization, 93% of all cases of malaria last year were in Africa. Despite the availability of drugs to treat malaria, the disease can be fatal and results in almost 500,000 deaths per year. Chloroquine and hydroxychloroquine are both prescribed to treat malaria. These ‘quinolone’ based drugs work by inhibiting the conversion of the digested blood inside the parasite into a form that it can dispose of. Instead, the hydroxychloroquine forms a complex with the digested blood and accumulation of this complex becomes toxic, leading to death of the parasite. 

Hydroxychloroquine has reduced efficacy on the parasite in areas where the parasite is not sensitive to chloroquine. People who travel to areas of the world where malaria is prevalent will often take hydroxychloroquine to prevent contracting the disease. In the United States, the large majority of malaria cases are seen in travellers returning from malaria-afflicted regions. 


Lupus is an autoimmune condition in which the immune system attacks healthy tissues in the body. Autoimmune conditions are most-often long-term diseases that have to be managed with regular intake of medication. Hydroxychloroquine, also known as the brand Plaquenil, is the first-line treatment drug for Lupus. Most patients are prescribed hydroxychloroquine when they are first diagnosed with the disease. Clinical trials in the early 1950s demonstrated the ability of hydroxychloroquine to significantly reduce certain symptoms of Discoid and Systemic Lupus Erythematous. Given the marked ability of anti-malarial drugs to help autoimmune diseases, they are now also classified as ‘disease-modifying anti-rheumatic drugs (DMARDs). These anti-malarial drugs, including hydroxychloroquine, have been found to reduce flares of the disease by up to 50%, and can prevent the disease from progressing to organs like the central nervous system. Many patients with Lupus will likely have to take hydroxychloroquine for the rest of their lives to keep the disease manageable. It is important to note that the anti-malarial drugs alone are not sufficient for the treatment of severe Lupus once it affects specific organs. In these cases, steroids or immunosuppressive drugs are usually prescribed. The mechanism that hydroxychloroquine uses in treating autoimmune disease is thought to be by decreasing the activity of the ‘innate immune system’ by interrupting immune cell-to-cell communication. 

Rheumatoid Arthritis

Rheumatoid arthritis is a chronic inflammatory condition that can affect most commonly the joints, but also other parts of the body like the skin, heart and lungs. It is an autoimmune condition that can cause severe pain due the swelling of joints and can eventually lead to bone deformities. There is no cure for Rheumatoid Arthritis, but certain medications can be prescribed to help alleviate the symptoms and make the disease manageable to live with. Hydroxychloroquine is FDA-approved to treat inflammatory arthritis like Rheumatoid Arthritis, Psoriatic Arthritis and Juvenile Idiopathic Arthritis (JIA). The benefit of hydroxychloroquine in treating Rheumatoid Arthritis was discovered in the early 1950s when the drug was first implemented for the treatment of Lupus. 

Sjögren’s Syndrome 

Sjögren’s Syndrome is an uncommon autoimmune disease that affects between 1.5 to 4 million Americans. In this condition, the moisture-producing glands in the body are attacked by the immune system, causing dry eyes and dry mouth as the most common symptoms.  Currently, hydroxychloroquine is the first-line therapy for the treatment of musculoskeletal pain associated with Sjögren’s Syndrome although it is not indicated by the FDA for this use. Even though it is prescribed to treat this disease, whether the drug actually works in alleviating symptoms is unclear. While some studies have seen a benefit with taking this drug in patients with Sjögren’s Syndrome, others have not. In 2017, a systematic review of four clinical trials found no significant difference in the occurrence of dry eyes and dry mouth in 215 patients with Sjögren’s Syndrome who took hydroxychloroquine. However, as Sjögren’s Syndrome is one of the more difficult autoimmune conditions to manage, hydroxychloroquine is routinely prescribed to patients that are diagnosed with this disease since some studies have judged there to be a benefit to taking the drug. 


Hydroxychloroquine, like the related drug chloroquine, is effective for the treatment of some infections caused by certain bacteria. The mechanism is most likely due to increase in pH of the naturally acidic environment of the organelles in the cell that are infected by the infection-causing microbe. Hydroxychloroquine is prescribed along with another antibiotic, doxycycline, for the treatment of Q-fever endocarditis, caused by the bacteria Coxiella burnetti. 

Antiviral (Emergency Use Authorization for COVID-19)

Studies of hydroxychloroquine have shown that it can inhibit the replication of the HIV virus and decrease the viral load of HIV patients. However, because current therapy for HIV with anti-retroviral drugs is quite strong, hydroxychloroquine is not prescribed for its treatment. During the Severe Respiratory Syndrome outbreak in 2002-2003 caused by a human coronavirus, it was shown that chloroquine could inhibit the replication of coronavirus in human cells in laboratory conditions outside of the body. Recently, due to the COVID-19 pandemic, research on whether hydroxychloroquine can clear an infection caused by the SARS-CoV-2 virus has resumed. But, rigorous clinical trials are necessary before any conclusion can be made on whether the drug is proven to work for treating COVID-19. The FDA has allowed ‘compassionate use’ of hydroxychloroquine for patients hospitalized with hydroxychloroquine that cannot be enrolled in a clinical trial, and physicians can decide whether to treat these patients with the drug. 

Additional Effects of Hydroxychloroquine

Hydroxychloroquine is being investigated for other less well-known effects as well. It has been reported to have effects on the metabolic system, like reducing glycemic levels and improving the lipid profile in patients who take it. It has also demonstrated anti-cancer effects, such as slowing the growth of cultured cancer cells and sensitizing cancer cells to radiation and chemotherapy. Hydroxychloroquine is not prescribed for these uses yet though, and several clinical trials are ongoing to understand how it works in the human body for these indications.  

How to purchase Hydroxychloroquine

Hydroxychloroquine is a versatile anti-malarial drug that can be prescribed for any of the conditions listed above. If you are prescribed hydroxychloroquine, you will need to take your prescription with you to the pharmacy to purchase it. Why is Hydroxychloroquine so expensive? The cost of hydroxychloroquine can be relatively quite high, which can become a cost burden on patients who have to take it regularly for chronic autoimmune conditions. A prescription drug discount card can help reduce these costs by providing a discounted price on the drug. A good option is the card from USA Rx, available here. The discount card is free, and can be presented to your pharmacy when filling your prescription to start saving on hydroxychloroquine. 


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Published April 26th, 2020 by Chris Riley
Fact Checked by
Chris Riley

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