You may have heard of hydroxychloroquine before. It was originally developed as an antimalarial drug, and it got a lot of attention during COVID, when it was touted as a possible treatment. It doesn't work for COVID. But it does work, and works well, for the conditions I treat.
When I start a patient on hydroxychloroquine, I usually describe it as the mildest medicine we have. It's also unique in rheumatology, because unlike most of our treatments, it isn't an immunosuppressant.
Let me walk through it.
What it's used for
Hydroxychloroquine (brand name Plaquenil) is a cornerstone treatment in rheumatology. We use it across a number of conditions:
- Systemic lupus erythematosus (SLE), where it's foundational. Nearly every lupus patient should be on it.
- Rheumatoid arthritis, often as part of combination therapy
- Other connective tissue diseases
In lupus especially, hydroxychloroquine isn't just for symptom control. It reduces flares, helps protect organs from damage, and improves long-term outcomes. It's one of the few medications that changes the trajectory of the disease, which is why we use it so broadly.
How it works
Hydroxychloroquine works differently than most of our other medications. Rather than suppressing the immune system, it modulates it. It interferes with specific signaling pathways that drive autoimmune inflammation, dampening the overactive immune response without shutting it down.
That's a big part of why it's so well-tolerated, and why it doesn't carry the same infection risk that comes with our immunosuppressive medications.
Why we like it
A few reasons hydroxychloroquine is used so widely:
- It's mild. The side effect profile is favorable compared to most rheumatology medications.
- It's not an immunosuppressant, so it doesn't increase infection risk.
- It's safe in pregnancy, which matters a lot given how many of our patients are women of childbearing age. In fact, we usually continue it during pregnancy because stopping it can trigger flares.
- It's inexpensive and has been around for decades, so we understand it well.
The eye exams
If there's one thing patients ask about with hydroxychloroquine, it's the eyes.
Over a long period of time, hydroxychloroquine can rarely deposit in the retina and cause damage. This is the one side effect we monitor for carefully. The key word is rarely. At correct, weight-based dosing, the risk is very low in the first few years of treatment and increases gradually with cumulative use over many years.
Because of this, we recommend a baseline eye exam when starting the medication, and regular screening exams (typically annually after five years of use, sometimes sooner depending on risk factors). The screening is sensitive enough to catch early changes well before they affect vision, and if anything shows up, we simply stop the medication.
This is a manageable, well-understood risk. It's not a reason to avoid the medication. It's a reason to stay on top of monitoring.
Other side effects
Most people tolerate hydroxychloroquine very well. When side effects do occur, they're usually mild:
- GI upset (nausea, stomach discomfort), often improved by taking it with food
- Skin changes, including rashes or changes in pigmentation
Most patients take it without any issues at all.
What to expect
One thing to know going in: hydroxychloroquine is very slow. It's not a medication you take and feel better the next day. It typically takes 3 to 6 months to reach its full effect, which is why I usually recommend giving it a full six-month trial before deciding whether it's working.
Once it's working, it tends to keep working quietly in the background, which is exactly what you want from a long-term medication.
The bottom line
Hydroxychloroquine has earned its place as one of the most widely used medications in rheumatology. It's mild, well-tolerated, safe in pregnancy, and makes a difference in conditions such as lupus and RA. The eye monitoring is a real consideration, but it's manageable and shouldn't overshadow how useful and well-understood this medication is.
If you've been prescribed hydroxychloroquine and have questions about it, bring them to your rheumatologist. It's a medication we know well and use with confidence.