Hydroxychloroquine

Antimalarials, aminoquinolines

ATC code: P01BA02

Brand names: Plaquenil

Updated 24 Sep 2026 · Methodology

Indications

Systemic lupus erythematosus

First line

Foundation therapy for all SLE patients regardless of severity per 2023, 2024, BSR 2018. Reduces flare frequency, organ damage, thromboembolic events, and all-cause mortality – the only drug with demonstrated benefit on long-term SLE outcomes. Dose 200–400 mg/day, not exceeding 5 mg/kg ideal body weight to prevent retinopathy. Effect develops over 3–6 months. Ophthalmologic exam at baseline, after 5 years, then annually.

Sources

ICD-10: M32 · ICD-11: 4A40

Rheumatoid arthritis

Second line

Per the 2022 update, hydroxychloroquine is used in mild rheumatoid arthritis or as part of combination therapy. Structural disease-modifying effect is weaker than methotrexate, so it is not first choice in active disease.

Sources

ICD-10: M06.9 · ICD-11: FA20

Marketing claims without evidence base

The drug is promoted for these uses outside international guidelines. Each entry below is analyzed against AEMPS, FDA, EMA, Cochrane and major RCTs.

Anti-aging and longevity

Not recommended

Hydroxychloroquine is an antimalarial and disease-modifying antirheumatic drug. It is prescribed for systemic lupus erythematosus, rheumatoid arthritis, discoid lupus erythematosus, and for malaria prevention and treatment ( 2023, 2020 guidelines). In anti-aging communities, low-dose hydroxychloroquine is positioned as an anti-aging and life-extension agent. In healthy adults, no clinical studies of such use exist; international anti-aging guidelines do not include hydroxychloroquine. The drug has serious risks on long-term use: irreversible retinopathy (with vision loss risk, requires ophthalmologic screening every 6–12 months), cardiomyopathy, myopathy, neuropathy, and QT prolongation. If hydroxychloroquine was recommended to a healthy person for anti-aging, consider seeking a second opinion.

Sources

Immune support and respiratory infection care

Not recommended

Hydroxychloroquine is an antimalarial and disease-modifying antirheumatic drug. It is prescribed for systemic lupus erythematosus, rheumatoid arthritis, discoid lupus erythematosus, and for malaria prevention and treatment ( 2023, 2020). In 2020 hydroxychloroquine was actively promoted as a COVID-19 treatment and prophylaxis. The RECOVERY (NEJM 2020) and Solidarity ( 2020) trials in tens of thousands of patients showed no benefit and a signal of increased mortality in hospitalized COVID-19 patients. WHO Living Guideline 2023 and NIH COVID-19 Guidelines 2024 strongly advise against hydroxychloroquine for COVID-19. The drug has serious risks on long-term use: irreversible retinopathy with vision-loss risk, QT prolongation, and cardiomyopathy. If hydroxychloroquine was recommended for COVID-19 or for immunity, consider seeking a second opinion.

Sources

How to read tiers A–F

AStrong evidence – first or second line in international guidelines
BRecommended in selected cases
CStudy data contradict each other
DBenefit not proven, no documented harm
FDocumented harm, or risk without benefit

Mechanism of action

Chloroquine derivative with a better safety profile. Accumulates in lysosomes, raises their pH, and disrupts macrophage, dendritic cell, T- and B-lymphocyte function. Suppresses toll-like receptors 7 and 9, reducing type I interferon production — a key mechanism in SLE. Effect develops over 3–6 months. The narrow window is not about efficacy but about retinopathy prevention — maximum 5 mg/kg ideal body weight per day.

Safety

Contraindications

Known retinopathy
G6PD deficiency
Severe hematological disease
Hypersensitivity to 4-aminoquinolines

Serious adverse effects

Hydroxychloroquine retinopathy (irreversible retinal damage at cumulative doses above 1000 g or duration over 5 years)
Cardiomyopathy with heart failure (rare, with long-term high-dose therapy)
QT prolongation
Severe hypoglycemia (rare)
Hemolytic anemia in G6PD-deficient patients
Severe cutaneous reactions (DRESS, SJS)

Common adverse effects

Dyspepsia, nausea, diarrhea
Skin rash, pruritus
Headache
Skin and mucosal hyperpigmentation (reversible)

Pregnancy: can you take Hydroxychloroquine?

AEMPS summary of product characteristics (section 4.6): hydroxychloroquine crosses the placenta, and fetal blood concentrations are similar to maternal ones; animal studies with the structurally related chloroquine showed reproductive toxicity at high maternal exposure. In a population-based cohort study of 2,045 exposed pregnancies, first-trimester exposure was associated with a small increase in the relative risk of congenital malformations: RR 1.33 (95% CI 1.08 to 1.65) at daily doses of 400 mg or more and 0.95 (95% CI 0.60 to 1.50) at lower doses. Hydroxychloroquine should be avoided in pregnancy unless, in the physician's judgement, the benefits outweigh the risks, and then the lowest effective dose is used. High daily doses (as for systemic lupus erythematosus, rheumatoid arthritis or an acute malaria attack) are given only under a strict indication and when the risk of stopping treatment is greater than the possible risk to the fetus; after prolonged use in pregnancy, the child's follow-up takes into account the drug's safety profile, especially its ophthalmological effects.

Breastfeeding: can you take Hydroxychloroquine?

Transfers into milk in small amounts. Compatible with breastfeeding per LactMed.

RID, infant dose via milk: 9.8%

Calculate RID Full profile on NIH LactMed ↗

Reference information, not a clinical decision. Discuss feeding pauses or changes with your physician or an IBCLC.

Practical notes

Timing and administration

Once daily in the morning with or after food — reduces dyspepsia. Skin and joint effects in SLE develop over 6–12 weeks; flare reduction over 3–6 months. Do not stop on achieving remission — the drug confers long-term protection.

Monitoring

Baseline ophthalmologic exam (visual acuity, visual fields, macular OCT, color vision). Repeat at 5 years, then annually. In patients with retinopathy risk factors (dose above 5 mg/kg, duration over 5 years, eGFR under 60, prior tamoxifen) — annually from start. Labs: CBC and metabolic panel every 6–12 months. New visual symptoms — urgent ophthalmologic evaluation and risk/benefit reassessment.

Label mentions21 mentions

Verbatim lines from the interaction sections, in the language of the label

From this drug’s label

Majorantidiabeticsclass named in the label
«Insulin or Other Antidiabetic Drugs: Hydroxychloroquine sulfate tablets may enhance the effects of insulin and antidiabetic drugs, and consequently increase the hypoglycemic risk. Therefore, a…»
FDA, section 7 · Open on DailyMed
Majorinsulinclass named in the label
«Insulin or Other Antidiabetic Drugs: Hydroxychloroquine sulfate tablets may enhance the effects of insulin and antidiabetic drugs, and consequently increase the hypoglycemic risk. Therefore, a…»
FDA, section 7 · Open on DailyMed
MajorRifampicin
«Rifampicin: Lack of efficacy of hydroxychloroquine was reported when rifampicin was concomitantly administered. Avoid concomitant use of rifampicin.»
FDA, section 7 · Open on DailyMed
Moderateantiarrítmicosclass named in the label
«La hidroxicloroquina se debe usar con precaución en pacientes que toman medicamentos que prolongan el intervalo QT, por ej. antiarrítmicos de clase IA y III, antidepresivos tricíclicos…»
AEMPS, section 4.5 · Open on CIMA
Moderateantidepresivos tricíclicosclass named in the label
«La hidroxicloroquina se debe usar con precaución en pacientes que toman medicamentos que prolongan el intervalo QT, por ej. antiarrítmicos de clase IA y III, antidepresivos tricíclicos…»
AEMPS, section 4.5 · Open on CIMA
Moderateantidiabéticosclass named in the label
«Hipoglucemia: Se ha demostrado que la hidroxicloroquina causa hipoglucemia severa incluyendo pérdida de consciencia que puede amenazar la vida en pacientes tratados con y sin medicamentos…»
AEMPS, section 4.4 · Open on CIMA
Moderateantipsicóticosclass named in the label
«La hidroxicloroquina se debe usar con precaución en pacientes que toman medicamentos que prolongan el intervalo QT, por ej. antiarrítmicos de clase IA y III, antidepresivos tricíclicos…»
AEMPS, section 4.5 · Open on CIMA
ModerateDigoxin
«Se ha informado que hidroxicloroquina sulfato aumenta los niveles plasmáticos de digoxina: los niveles séricos de digoxina deben controlarse estrechamente en pacientes que reciben tratamiento…»
AEMPS, section 4.5 · Open on CIMA
ModerateDigoxin
«Digoxin: Concomitant hydroxychloroquine sulfate tablets and digoxin therapy may result in increased serum digoxin levels. Monitor serum digoxin levels closely in patients receiving combined therapy.»
FDA, section 7 · Open on DailyMed
antacidsclass named in the label
«Antacids and kaolin: Antacids and kaolin can reduce absorption of chloroquine; an interval of at least 4 hours between intake of these agents and chloroquine should be observed. Interaction of…»
FDA, section 7 · Open on DailyMed
antiepilépticosclass named in the label
«La actividad de los medicamentos antiepilépticos puede verse afectada si se administra de forma conjunta con hidroxicloroquina.»
AEMPS, section 4.5 · Open on CIMA
antiepilepticsclass named in the label
«Antiepileptics: The activity of antiepileptic drugs might be impaired if co-administered with hydroxychloroquine sulfate tablets.»
FDA, section 7 · Open on DailyMed
Insulin
«Como hidroxicloroquina puede aumentar los efectos de un tratamiento hipoglucemiante, puede requerirse una disminución de las dosis de insulina o medicamentos antidiabéticos.»
AEMPS, section 4.5 · Open on CIMA
insulinaclass named in the label
«Como hidroxicloroquina puede aumentar los efectos de un tratamiento hipoglucemiante, puede requerirse una disminución de las dosis de insulina o medicamentos antidiabéticos.»
AEMPS, section 4.5 · Open on CIMA
Methotrexate
«Methotrexate: Concomitant use of hydroxychloroquine sulfate tablets and methotrexate may increase the incidence of adverse reactions.»
FDA, section 7 · Open on DailyMed

From other drugs’ labels

MajorLeflunomide
«Combinaciones con otros tratamientos: Hasta el momento no se ha estudiado suficientemente en ensayos aleatorizados (a excepción del metotrexato, ver sección 4.5) el empleo de la leflunomida con los…»
AEMPS, section 4.4 · Open on CIMA
ModerateAzithromycin
«Medicamentos asociados con prolongación del intervalo QT: Azitromicina se debe usar con precaución en pacientes que reciben medicamentos que se sabe que prolongan el intervalo QT (ver sección 4.4)…»
AEMPS, section 4.5 · Open on CIMA
ModerateClarithromycin
«Claritromicina debe utilizarse con precaución en pacientes que toman hidroxicloroquina y cloroquina conocidos por prolongar el intervalo QT debido a la posibilidad de inducir arritmia cardíaca y…»
AEMPS, section 4.5 · Open on CIMA
ModerateErythromycin
«Medicamentos que prolongan el intervalo QT: Hidroxicloroquina y cloroquina: la eritromicina debe usarse con precaución en los pacientes que reciban estos medicamentos que se sabe que prolongan el…»
AEMPS, section 4.5 · Open on CIMA
Dexamethasone
«Cloroquina, hidroxicloroquina y mefloquina: Aumentan el riesgo de miopatías y cardiomiopatías.»
AEMPS, section 4.5 · Open on CIMA
Methotrexate
«Por lo general, no se espera un aumento de los efectos tóxicos del metotrexato cuando se administra Metoject PEN simultáneamente con otros medicamentos antirreumáticos (p. ej., sales de oro…»
AEMPS, section 4.5 · Open on CIMA

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Frequently asked

What is Hydroxychloroquine used for?

Hydroxychloroquine is evaluated for the following indications with varying evidence strength: Systemic lupus erythematosus (evidence tier A), Rheumatoid arthritis (evidence tier B), Immune support and respiratory infection care (evidence tier F). See the full indication matrix with dosing and citations above on this page.

What are the side effects of Hydroxychloroquine?

Common side effects of Hydroxychloroquine (≥ 1 in 100): Dyspepsia, nausea, diarrhea, Skin rash, pruritus, Headache, Skin and mucosal hyperpigmentation (reversible). See the Safety section for uncommon and serious reactions.

Is Hydroxychloroquine safe during pregnancy?

Is Hydroxychloroquine compatible with breastfeeding?

Transfers into milk in small amounts. Compatible with breastfeeding per LactMed.

Who should not take Hydroxychloroquine?

Hydroxychloroquine is contraindicated in: Known retinopathy; G6PD deficiency; Severe hematological disease; Hypersensitivity to 4-aminoquinolines. Full list in the Safety section.

Official sources

Direct links to regulator labels. Open in a new tab.

AEMPS / CIMALabel dated 02/04/2026
FDA / DailyMedLabel dated 06/08/2026

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