Hydroxychloroquine is not a steroid. It belongs to a completely different drug class called antimalarials, originally developed to prevent and treat malaria. It is also classified as an antirheumatic drug, meaning it helps manage certain autoimmune conditions. The confusion likely comes from the fact that hydroxychloroquine and steroids are often prescribed for the same diseases, sometimes even together, but they work in fundamentally different ways inside your body.
What Class of Drug Is Hydroxychloroquine?
Hydroxychloroquine is a 4-aminoquinoline, a synthetic compound built around two fused aromatic rings. Steroids, by contrast, share a distinctive four-ring carbon structure that allows them to mimic hormones like cortisol. The two molecules look nothing alike at the chemical level, and they interact with entirely different biological pathways.
Hydroxychloroquine works by slipping into the tiny acidic compartments inside your cells (lysosomes and endosomes) and raising their pH. Normally, these compartments sit at a pH around 4. Hydroxychloroquine pushes that closer to 6. That shift disrupts the enzymes inside those compartments and blocks certain immune sensors from detecting and overreacting to the body’s own genetic material. In autoimmune diseases, those sensors can mistakenly trigger inflammation against healthy tissue, so quieting them down helps control symptoms.
There’s also a second, subtler mechanism. At low concentrations, hydroxychloroquine can physically bind to fragments of DNA and RNA floating in those compartments, changing their shape so the immune sensors can’t latch onto them in the first place. This is a very different approach from steroids, which broadly suppress the immune system by turning down the production of inflammatory proteins across many cell types at once.
How Steroids Work Differently
Corticosteroids (the type used for autoimmune diseases, not the muscle-building kind) are synthetic versions of cortisol, a hormone your adrenal glands produce naturally. They enter cells, bind to receptors in the nucleus, and directly dial down the activity of genes responsible for producing inflammation. This makes them powerful and fast-acting, which is why they’re often the first drug used to bring a severe flare under control.
The tradeoff is that because steroids affect so many systems at once, long-term use comes with significant side effects: bone thinning, weight gain, elevated blood sugar, increased infection risk, and mood changes, among others. In a head-to-head comparison of hydroxychloroquine and corticosteroids for a type of kidney disease, 6.5% of patients on corticosteroids experienced serious adverse events, while none in the hydroxychloroquine group did. That safety gap is one reason doctors try to minimize steroid use whenever possible.
Why They’re Often Prescribed Together
In conditions like lupus, hydroxychloroquine and steroids play complementary but distinct roles. Hydroxychloroquine is considered the backbone of lupus treatment. It reduces the number and severity of flares, slows the accumulation of organ damage over time, and has even been shown to improve long-term survival. But it works gradually, often taking weeks to months before its full benefits are noticeable.
Steroids fill the gap that hydroxychloroquine can’t. When a lupus flare hits and inflammation needs to be controlled quickly, corticosteroids are the most effective tool for inducing rapid remission. The current treatment strategy pairs early, universal use of hydroxychloroquine with short pulses of steroids during active disease. This combination allows doctors to bring flares under control fast while reducing the total amount of steroid exposure a patient needs over their lifetime, limiting the damage steroids themselves can cause to bones, the cardiovascular system, and other organs.
Side Effects to Know About
Because hydroxychloroquine is not a steroid, its side effect profile looks very different. You won’t experience the weight gain, puffy face, blood sugar spikes, or bone loss associated with long-term steroid use. The primary long-term concern with hydroxychloroquine is its potential to damage the retina, the light-sensing tissue at the back of your eye. The risk is low in the first several years of use but increases with higher doses and longer duration.
To minimize that risk, the American Academy of Ophthalmology recommends keeping the dose at or below 5 mg per kilogram of actual body weight per day. For someone weighing 150 pounds (about 68 kg), that works out to roughly 340 mg daily. Regular eye screenings, typically starting after five years of use, help catch any early retinal changes before vision is affected. Other possible side effects include nausea, stomach cramps, and, less commonly, skin reactions or muscle weakness, but these tend to be mild compared to the complications associated with long-term steroid therapy.
Quick Comparison at a Glance
- Drug class: Hydroxychloroquine is an antimalarial/antirheumatic. Corticosteroids are synthetic hormones.
- Speed: Steroids work within hours to days. Hydroxychloroquine takes weeks to months for full effect.
- Role: Steroids control acute flares. Hydroxychloroquine prevents flares and protects organs long-term.
- Key risk with long-term use: Steroids carry risks of bone loss, weight gain, and metabolic changes. Hydroxychloroquine carries a risk of retinal damage at higher doses.
- Serious adverse events: Significantly more common with steroids than with hydroxychloroquine in direct comparisons.