What is hydroxychloroquine?
Hydroxychloroquine (brand name Plaquenil) is one of the most widely used and best-tolerated medications in rheumatology. It’s a cornerstone of treatment for lupus (SLE) and is also used for rheumatoid arthritis, Sjögren’s syndrome, and other connective tissue diseases.
Originally developed as an antimalarial drug, hydroxychloroquine works by modulating the immune system in several ways — reducing inflammation, calming overactive immune signaling, and decreasing the production of harmful autoantibodies. Beyond joint and skin benefits, it may also have cardiovascular protective effects and help reduce the risk of blood clots in lupus patients.
Hydroxychloroquine is considered one of the safest long-term DMARDs available, which is why it’s often the first medication we reach for — and one we’re comfortable keeping patients on for many years.
How to take it
- Typical dose: 200–400 mg daily, usually taken once or twice a day.
- Dosing is weight-based — we aim for no more than 5 mg/kg of actual body weight per day to minimize long-term risk.
- Take with food to reduce the chance of stomach upset.
- Can be taken at any time of day, but staying consistent helps build a routine.
What to expect when starting
Hydroxychloroquine is one of the slower-acting DMARDs. Most patients notice improvement in 2–3 months, and it can take up to 6 months for the full effect. This is normal — stick with it.
You may notice gradual improvements in:
- Joint pain and stiffness
- Fatigue (one of its most appreciated benefits)
- Skin rashes related to lupus or other autoimmune conditions
- Overall sense of well-being
When starting, some patients experience mild stomach upset or nausea, which usually resolves within a few weeks — especially if taken with food.
Lab monitoring
One of the advantages of hydroxychloroquine is that routine blood work is generally not needed for monitoring the drug itself. This makes it one of the lowest-maintenance medications in rheumatology.
However, there is one important monitoring requirement — eye exams (see below).
Eye screening: what you need to know
The most important long-term consideration with hydroxychloroquine is the risk of retinal toxicity (damage to the retina at the back of the eye). Here’s what you should know:
- The risk is dose-dependent and time-dependent. At the recommended dose of 5 mg/kg/day or less, the risk in the first 5 years is very low — less than 1%.
- The risk gradually increases after 5 or more years of continuous use, particularly at higher doses.
- We screen for this with an annual eye exam that includes OCT (optical coherence tomography), a quick, painless imaging scan of your retina. Screening typically starts at the 5-year mark, or sooner if you have risk factors like kidney disease.
- If early changes are detected on screening, they are reversible by stopping the medication.
The bottom line: We monitor your eyes precisely so that this remains a safe medication for you. Retinopathy is rare, detectable, and manageable. It should not be a reason to avoid a drug that provides enormous benefits. We watch for it so you don’t have to worry about it.
Side effects to watch for
Hydroxychloroquine is generally very well tolerated. Contact us if you experience:
- Persistent nausea or stomach upset that doesn’t improve with food
- Skin rash or unusual skin darkening
- Muscle weakness
- Changes in vision — blurred vision, difficulty reading, or seeing light flashes (rare, but contact us and your eye doctor promptly)
Things to avoid
- Pre-existing macular disease — if you have known retinal or macular problems, let us know before starting. This may affect dosing decisions or require earlier eye screening.
- Hydroxychloroquine has very few drug interactions and very few restrictions, which is part of what makes it so practical for long-term use.
Frequently asked questions
Should I be worried about my eyes? This is the most common concern we hear, and the answer is: not if we’re monitoring appropriately. At proper doses, the risk of retinal toxicity in the first 5 years is under 1%. After 5 years, the risk increases slowly, which is why we begin annual screening. If changes appear on an OCT scan, we catch them early — well before vision is affected — and stopping the medication reverses the process. The benefits of hydroxychloroquine for lupus and other conditions far outweigh this manageable risk.
Can I take it during pregnancy? Yes. Hydroxychloroquine is one of the few DMARDs considered safe during pregnancy and breastfeeding. In fact, for lupus patients, continuing hydroxychloroquine during pregnancy is strongly recommended because it reduces the risk of lupus flares.
Do I need blood work? Not specifically for hydroxychloroquine. Your rheumatologist may still order labs to monitor your underlying condition, but the medication itself doesn’t require routine blood test monitoring.
What if I miss a dose? Take it when you remember. If it’s almost time for your next dose, just skip the missed one. Hydroxychloroquine has a very long half-life, so missing a single dose won’t cause problems.
How long will I need to take it? Many patients take hydroxychloroquine for years or even lifelong — especially with lupus, where it is considered a foundational therapy. Because it’s so well tolerated and provides ongoing protection against flares, organ damage, and cardiovascular risk, we generally recommend staying on it unless there’s a specific reason to stop.
I heard about hydroxychloroquine during COVID — is this the same drug? Yes, it’s the same medication. Hydroxychloroquine was studied early in the pandemic but was ultimately found not to be effective for preventing or treating COVID-19. Its proven benefits remain in rheumatology, where it has decades of evidence supporting its use.
This handout is provided for educational purposes and does not replace individualized medical advice. Always follow the specific instructions given by your rheumatologist.