Hydroxychloroquine is an antimalarial and anti-rheumatic medication primarily used to treat malaria. It can also help in the management of autoimmune conditions like rheumatoid arthritis and lupus.

In this article, we explore everything you need to know about hydroxychloroquine, including why it’s used, how it works, its most common side effects, and how you can take it safely.

Here’s the breakdown. 

What is hydroxychloroquine, and how does it work?

Hydroxychloroquine is an antimalarial and disease-modifying anti-rheumatic (DMARD) medication. It’s also known as hydroxychloroquine sulfate.

Common brands include Plaquenil®, Quineprox®, and SOVUNA®.

Hydroxychloroquine is widely approved for the following conditions:

• Malaria
• Rheumatoid arthritis
• Systemic lupus erythematosus (SLE)
• Chronic discoid lupus erythematosus

The medication may be prescribed off-label for other autoimmune conditions.

Researchers are not completely clear on how the drug works in people with malaria. It is thought to work by interfering with how the parasite processes hemoglobin inside red blood cells. This leads to a buildup of toxic substances within the parasite, which ultimately causes it to die.

Hydroxychloroquine helps manage autoimmune conditions by reducing overactivity in the immune system. This helps protect healthy cells during a flare and lessens inflammation.

Hydroxychloroquine for lupus

If you have lupus, your doctor may prescribe hydroxychloroquine to help reduce your risk of experiencing a flare-up.

When the immune system works properly, it helps defend the body against potentially dangerous pathogens. Moving through the blood, immune cells find, target, and kill bacteria and viruses that may cause harm.

With lupus, the immune system becomes overactive. A period of overactivity is known as a “flare-up.” During a flare, the immune system targets and damages healthy cells in the organs and tissues. Over time, this can lead to inflammation and tissue damage, which causes a wide range of symptoms, including skin rashes, fatigue, and joint pain.

This is where hydroxychloroquine can help. It reduces immune activity, which helps lessen the frequency and severity of flares.

Taking hydroxychloroquine for lupus doesn’t usually relieve symptoms during an active flare. Instead, it’s taken regularly over time to help reduce the risk of future flare-ups.

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How to take hydroxychloroquine

Hydroxychloroquine is taken orally as a tablet. Do not crush, cut, or chew the medication. When possible, it’s best to take it with water or food.

Only take hydroxychloroquine as prescribed by your doctor. Do not stop taking the medication suddenly or earlier than your doctor advises, even if you start to feel better.

What to do if you miss a dose

Take a missed dose as soon as you can.

If it is close to the timing of your next dose, don’t take two doses together. Never double your doses to make up for missed ones.

Side effects of hydroxychloroquine

Like other medications, hydroxychloroquine can cause side effects. It’s important to monitor them, especially during the early stages of taking the drug.

Common side effects

• Headache
• Loss of appetite
• Nausea
• Diarrhea
• Vomiting
• Stomach pain
• Ringing in the ears (tinnitus)
• Difficulty hearing
• Hair loss
• Hair color changes

If you experience any of these side effects while taking the medication, speak to your doctor.

Serious side effects

In very rare cases, people have stronger reactions while taking hydroxychloroquine. If you experience any of the following side effects while taking the medication, contact your doctor or the emergency services immediately:

• Hives or rash on the face, mouth, throat, tongue, lips, feet, ankles, or legs
• Difficulty swallowing
• Skin blisters
• Muscle weakness
• Burning or numbness in the hands or feet
• Excessive fatigue
• Yellowing of the eyes or skin
• Mood or mental health changes
• Fast or regular heartbeat
• Dizziness or fainting
• Seizures
• Vision changes (such as blurred vision or seeing flashes of light)

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Who should not take hydroxychloroquine?

Hydroxychloroquine isn’t a safe medication option for everyone.

Before taking the drug, be sure to disclose your medical history to your doctor. They will consider whether it’s safe for you to take.

Tell your doctor if you have a history of any of the following:

• Diabetes
• Eye disease or visual problems
• Alcohol misuse
• Heart disease
• Irregular heart rhythm
• Kidney disease
• Liver disease
• Psoraisis
• Allergic reactions to other medications in the past

You must also tell your doctor if you are pregnant, planning a pregnancy, or breastfeeding.

Hydroxychloroquine and eye health

Hydroxychloroquine can cause ocular damage.

Before starting therapy, you may be advised to have an eye exam to collect baseline information about your visual health.

While taking the medication, regular eye checks are recommended to monitor for any changes. This is especially important for people who have taken hydroxychloroquine for 10 years or longer.

If you notice changes to your vision while taking the medication, contact your doctor immediately. They may recommend a lower dose or that you stop taking the medication altogether to reduce your risk of further damage.

Hydroxychloroquine overdose

It is possible to take too much hydroxychloroquine, causing an overdose. If you or someone you love has taken more than prescribed, immediately call poison control or the emergency services for support.

Symptoms of hydroxychloroquine overdose include:

• Fast or irregular heartbeat
• Dizziness or fainting
• Visual hallucinations
• Vision problems, such as temporary blindness
• Seizures
• Loss of consciousness

Measure progress over months, not days

Living with an autoimmune condition like lupus means symptoms can change day by day. Because of this, it can be difficult to see whether a treatment is working in the short term.

If you or someone you love is starting hydroxychloroquine therapy, diligently tracking your symptoms and any side effects over time can be incredibly valuable—and you can do this with the Human Health app.

This information can then be easily shared with your medical team to assess your treatment plan and make any adjustments to fit your specific needs.

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Frequently asked questions

How long can I stay on hydroxychloroquine?

It’s common for people to take hydrochloroquine for long periods of time, especially to manage an autoimmune condition. People taking hydroxychloroquine for lupus or rheumatoid arthritis, for example, may take the medication for years, if not indefinitely, to reduce flare-ups.

While long-term hydrochloroquine therapy is considered safe, your doctor will monitor you regularly. You may also be required to undergo regular eye check-ups, as retinal damage is a possible side effect of long-term therapy.

What conditions is hydroxychloroquine used for?

Hydroxychloroquine is prescribed to treat malaria and autoimmune conditions, including systemic lupus erythematosus and rheumatoid arthritis.

Is hydroxychloroquine safe?

Taking hydroxychloroquine is generally considered safe when taken as directed by a doctor. Like all medications, it can cause side effects, and some are more serious than others.

If you experience prolonged side effects or serious side effects, contact your doctor immediately.

It’s possible to overdose on hydroxychloroquine. For this reason, never double-dose or take more of the medication than you have been prescribed.

Who can take hydroxychloroquine?

Hydroxychloroquine can be prescribed to adults, seniors, and children who weigh at least 31 kg (68 lbs). The dosage depends on the person and the condition the medication is being used to treat.

People with existing medical conditions like psoriasis, liver disease, kidney disease, or a history of poor visual health may not be good candidates for hydroxychloroquine therapy.

Disclaimer: Human Health is a health tracking platform and does not provide medical advice, diagnosis, or treatment. The information in this guide is for educational purposes only and is not a substitute for professional medical care. Always consult your doctor or healthcare provider with questions about your health.

Sources:

1. Hydroxychloroquine, Cleveland Clinic
2. Chloroquine and hydroxychloroquine in the treatment of malaria and repurposing in treating COVID-19 (2020)
3. Hydroxychloroquine sulfate tablets, The Food and Drug Administration
4. Hydroxychloroquine (oral route), Mayo Clinic
5. Hydroxychloroquine, MedlinePlus
6. Hydroxychloroquine: an old drug with new relevance (2018)
7. Protecting your eyesight when taking plaquenil, The Lupus Foundation of America
8. Hydroxychloroquine (Plaquinil): benefits, side effects, and dosing, The Lupus Foundation of America