Hydroxychloroquine

Hydroxychloroquine (HCQ) is a familiar medicine for malaria and autoimmune conditions like lupus and rheumatoid arthritis. It’s taken by mouth, usually once a day, and works slowly to reduce flare-ups and inflammation. If you’ve been prescribed HCQ—or are wondering if it’s right for you—this page gives the clear, practical facts you need.

What hydroxychloroquine does

HCQ calms parts of the immune system that cause inflammation. In lupus it can lower skin and joint flares, protect organs, and may cut the chance of blood clots. In rheumatoid arthritis it’s often used with other drugs to improve symptoms and slow joint damage. Expect benefits over weeks to months, not instant relief.

Typical adult doses fall around 200–400 mg a day, but the safest dosing is weight-based. Clinicians aim to keep daily dose at or under 5 mg per kg of actual body weight to reduce long-term eye risk. Never change your dose without checking with your prescriber.

Side effects, monitoring & safe use

Many people tolerate HCQ well. Common side effects: mild stomach upset, headache, and occasional rash. A rare but serious problem is eye toxicity that can cause permanent vision loss if it’s not caught early. That’s why a baseline eye exam is recommended soon after starting HCQ and regular screening—often yearly after five years of use or earlier with higher doses or other risk factors.

Other possible issues: muscle weakness, changes in blood counts, and interactions with drugs that affect heart rhythm. HCQ can lengthen the QT interval in some people, so avoid combining it with other QT-prolonging medicines unless a doctor agrees. Always tell your prescriber about all medicines and supplements you take.

During the COVID-19 pandemic HCQ got a lot of attention. For most people and most uses, strong studies did not support routine use for COVID. Don’t take HCQ for COVID unless a qualified clinician specifically prescribes it for your situation.

Practical tips: take HCQ with food to ease stomach upset, store tablets at room temperature, and don’t use online sources that skip prescriptions. If you notice blurry vision, dark spots, trouble reading, or changes in night vision, stop and contact your doctor right away.

Pregnancy and breastfeeding: HCQ is often continued for pregnant women with lupus because uncontrolled disease can harm mother and baby more than the drug. Still, discuss risks and benefits with your obstetrician and rheumatologist.

Considering alternatives? If HCQ isn’t working or causes problems, other disease-modifying drugs exist—methotrexate, sulfasalazine, leflunomide, or biologics. Each choice has different side effects, monitoring needs, and costs. Our article “Top Hydroxychloroquine Alternatives: 2025 Rheumatologist Guide” dives into those options.

Questions to ask your doctor: What dose fits my weight and condition? When should I get eye screening—and who arranges it? How long until I notice improvement? What are back-up options if HCQ isn’t right? Keep these handy for your next visit.

Used correctly and monitored, HCQ can be an effective, low-cost option for many people with autoimmune disease. Stay on top of eye checks and routine blood tests, follow dosing advice, and keep open communication with your healthcare team.