Hydroxychloroquine is one of the most closely studied drugs in modern rheumatology, with decades of use in adults, children, and pregnant women who live with lupus, juvenile arthritis, and related autoimmune conditions. This article lays out what controlled trials, cohort studies, and long-term registries actually show about its use across the lifespan — where the evidence is solid, where it is more limited, and what remains a matter of clinical judgment between a patient and her own physician.
A Medicine With a Long, Well-Studied History
Hydroxychloroquine descends from quinine, a compound isolated from the bark of the South American cinchona tree, and from chloroquine, developed in the mid-twentieth century for malaria. That a molecule drawn from tree bark would go on to calm an overactive immune system in lupus and rheumatoid arthritis is one of those quiet reminders that the natural world contains resources we are still learning to use well. Hydroxychloroquine has been approved by the FDA since 1955, initially for malaria and later for systemic lupus erythematosus, discoid lupus, and rheumatoid arthritis. That long track record — many decades, millions of patient-years — is precisely why it has such a well-characterized safety profile compared with newer immunosuppressive drugs, and why regulators and specialty societies have been able to issue fairly specific guidance on its use in vulnerable populations.
Children and Adolescents: Established Roles, Off-Label Use
Hydroxychloroquine is FDA-approved for malaria prophylaxis and treatment in children, with weight-based dosing (commonly around 5 mg/kg of base weekly for prevention, started one to two weeks before travel to an endemic area). This pediatric malaria use has a long, uncontroversial history.
Its use in childhood-onset lupus and juvenile idiopathic arthritis is different: it is off-label, meaning the FDA has not formally approved it for these indications in children, even though rheumatologists have prescribed it this way for decades and pediatric rheumatology guidelines from the American College of Rheumatology and the European Alliance of Associations for Rheumatology recommend it as a foundational therapy for childhood lupus. The rationale rests on extensive clinical experience and observational data showing reduced flare frequency and organ damage in children maintained on the drug, alongside its comparatively favorable side-effect profile next to steroids or stronger immunosuppressants used for the same disease.
Typical dosing in children with lupus or arthritis runs around 4–5 mg/kg per day of actual body weight, not to exceed adult maximums, because higher relative doses raise the risk of retinal toxicity over time. Because tablets are manufactured as 200 mg units (155 mg base), precise weight-based dosing in small children can require compounding or careful tablet-splitting under a pharmacist's guidance — a detail worth raising directly with the prescribing physician rather than assuming a standard adult tablet is appropriate. Parents should also know that regular eye examinations become part of long-term follow-up once a child has been on the drug for several years, following the same principles used in adults.
Pregnancy: What the Evidence on Safety Actually Shows
This is the area where the evidence base has shifted most clearly over the past twenty years, and where it now points toward continuation rather than discontinuation for women who need it. Older concerns about antimalarial drugs in pregnancy were based largely on chloroquine, a related but distinct compound, and on limited early case reports. Since then, several substantial cohort studies — notably work from French rheumatology and obstetric centers affiliated with Assistance Publique–Hôpitaux de Paris, published in journals including Arthritis & Rheumatism in the early 2000s and again in the following decade — followed pregnant women with lupus who continued hydroxychloroquine throughout pregnancy. These studies found no increased rate of birth defects, miscarriage, or growth restriction attributable to the drug, and importantly found that women who stopped it were more likely to suffer a lupus flare during pregnancy, which itself carries real risk to both mother and child.
The multi-center PROMISSE study, a prospective cohort of pregnant women with lupus and antiphospholipid antibodies conducted at several American academic centers and published in Annals of Internal Medicine around 2015, reinforced this picture of disease activity, not the medication, as the primary driver of adverse pregnancy outcomes. Separately, research groups at New York University have investigated whether hydroxychloroquine reduces the recurrence of congenital heart block in babies of mothers who carry anti-Ro/SSA antibodies — a rare but serious condition — with early trial data suggesting a protective effect, though this remains an area of continued study rather than settled practice.
On the strength of this accumulated evidence, the American College of Rheumatology's 2020 reproductive health guideline recommends that women with lupus continue hydroxychloroquine throughout pregnancy rather than stop it out of caution. This is a meaningful example of medicine correcting an earlier, more conservative default once real data accumulated — and it is a case where protecting the mother's health and protecting the unborn child's wellbeing point in the same direction, since untreated maternal disease flares are themselves a documented risk to the pregnancy. None of this substitutes for individualized care: any pregnant woman on hydroxychloroquine should be followed jointly by her rheumatologist and an obstetric provider familiar with high-risk pregnancy, and decisions about continuing or adjusting any medication in pregnancy belong to her and her physicians together.
Breastfeeding: Small Transfer, Reassuring Data
Hydroxychloroquine does pass into breast milk, but studies measuring actual concentrations — including work by the same French research groups that studied pregnancy outcomes — have found the amount transferred to be small relative to therapeutic pediatric doses, and infant plasma levels in nursing babies have generally been low or undetectable. The National Institutes of Health's LactMed database and the American Academy of Pediatrics both classify hydroxychloroquine as compatible with breastfeeding. No consistent pattern of adverse effects in breastfed infants has been reported in the available literature. As with any medication during lactation, a mother should discuss her specific situation with her physician and her baby's pediatrician, particularly if the infant has any underlying condition, but the existing evidence does not support routine avoidance of breastfeeding on account of this drug.
Older Adults: Same Medicine, Different Risks
Hydroxychloroquine is not dosed differently by age alone — there is no separate "elderly dose" — but older adults carry a different risk profile that deserves deliberate attention. Three issues matter most:
- Kidney function. The drug is cleared partly through the kidneys, and renal function commonly declines with age. Reduced clearance raises drug levels and, over time, raises the risk of retinal toxicity, so dosing should account for actual kidney function, not just body weight.
- Retinopathy risk and screening. The American Academy of Ophthalmology's 2016 revised guidance recommends dosing at or below roughly 5 mg/kg of real body weight per day and recommends baseline eye examinations followed by annual screening after five years of use, sooner if risk factors such as kidney disease, tamoxifen use, or pre-existing macular disease are present — all of which are more common in older patients. Age-related macular degeneration can also make screening more complex to interpret, so ophthalmologists experienced in this specific screening protocol are valuable.
- Cardiac and drug-interaction considerations. Hydroxychloroquine can affect heart rhythm in rare cases, particularly prolonging the QT interval, and older adults are more likely to be taking other medications that carry the same effect or to have underlying heart disease. A full medication review with a physician or pharmacist is a reasonable and low-cost safeguard before starting or continuing the drug.
None of this means hydroxychloroquine is unsafe for older patients — it remains a mainstay treatment for lupus and rheumatoid arthritis in people well into their eighties and beyond — but it does mean that routine monitoring is not a formality. Keeping a personal record of eye exams, kidney function tests, and current medications, and bringing that record to every appointment, is a simple act of stewardship that puts the patient, rather than the system, in charge of catching problems early.
A Necessary Word on COVID-19
Much recent public interest in hydroxychloroquine, including searches for specific tablet strengths, stems from its investigation as a possible COVID-19 treatment in 2020. Large randomized controlled trials — most notably the RECOVERY trial run by Oxford University in the United Kingdom, published in 2020 — found no reduction in mortality or recovery time among hospitalized COVID-19 patients given hydroxychloroquine, and the FDA revoked its emergency authorization for that use. Hydroxychloroquine is not FDA-approved for the prevention or treatment of COVID-19, and this article's discussion of its use in children, pregnancy, and older adults refers strictly to its established indications: malaria and autoimmune disease. Patients considering any off-label use of any medication should raise that specifically with their own physician rather than relying on general information.
Key takeaway: Hydroxychloroquine has decades of documented use in children, pregnant women, nursing mothers, and older adults for its approved indications, and the strongest evidence supports careful, individualized dosing with regular monitoring rather than blanket avoidance or unsupervised use.