Hydroxychloroquine: Eye Checks, Retina & How to Take It

Hydroxychloroquine: doses and eye appointments under control

A daily reminder, your weekly schedule and the next retinal check in one place — free in the brite app.

At a Glance: Technical Data Sheet
How it works: a gentle brake with a long memory
Dosing: why body weight counts
Taking it in everyday life
Side effects: from the stomach to the heart
Eye checks: retinal screening
Interactions: tamoxifen, QT interval, blood sugar
Further checks: blood count, kidneys, heart
Special situations: pregnancy, children, stopping
Hydroxychloroquine experiences: what patients really ask
FAQ: Common questions about hydroxychloroquine

1. At a Glance: Technical Data Sheet

Property	Details
Active ingredient	Hydroxychloroquine (as hydroxychloroquine sulfate)
ATC code	P01BA02
Drug class	4-aminoquinoline, antimalarial; used in rheumatology as a disease-modifying drug
Dosage forms	Film-coated tablets (200 mg hydroxychloroquine sulfate)
Half-life	Very long: terminal half-life of 30 to 50 days according to the SmPC
Maximum daily dose	Maintenance dose in rheumatoid arthritis and lupus usually 200 to 400 mg according to the SmPC; the ophthalmology guideline recommends no more than 5 mg per kg of body weight per day
Onset of effect	Slow: success can be judged after 4 to 12 weeks at the earliest
Prescription status	Prescription-only medicine
Notable feature	Dose- and duration-dependent risk of incurable retinal damage — regular eye checks are needed; life-threatening in overdose, especially in children

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2. How it works: a gentle brake with a long memory

Hydroxychloroquine is a weak base. It accumulates in the acidic "recycling chambers" of cells, the lysosomes, and makes them less acidic. Immune cells need precisely these chambers to break down foreign components — or, in autoimmune diseases, the body's own — and present them to the immune system as an alarm signal. Hydroxychloroquine also dampens certain receptors that recognise fragments of genetic material and play a central role in lupus. The mechanism has not been fully clarified — the SmPC speaks cautiously of a possible dampening of immune reactions.^¹

The result is a gentle dampening of the autoimmune reaction, not broad immunosuppression as with azathioprine. In systemic lupus erythematosus, the European guidelines therefore recommend hydroxychloroquine for everyone affected unless there is a reason against it: it reduces the number of flares and is associated with less organ damage and a better long-term outlook.^² In rheumatoid arthritis its effect on its own is rather moderate; there it is usually combined with other disease-modifying drugs such as methotrexate.

The problems also follow from its chemistry. Hydroxychloroquine binds strongly to pigment (melanin). According to the SmPC, it reaches up to a thousand times its blood concentration in pigmented cells.^¹ These include the pigment epithelium of the retina, the layer that supplies the light-sensing cells. Over the years, so much can build up there that the light-sensing cells are damaged — the core of this article. The enormous storage in tissue also explains the long half-life of 30 to 50 days: effects and side effects build up slowly and fade just as slowly after stopping.

Important for context. Hydroxychloroquine is not a painkiller and not a remedy for an acute flare. It has a stabilising effect over months. If you "don't notice anything" after four weeks, you are within the expected time frame — this is not treatment failure.

3. Dosing: why body weight counts

The figures below describe what the SmPC and the guideline state. They are not a dosing instruction — your dose is set by the treating practice.

According to the SmPC, adults with rheumatoid arthritis or lupus start with a higher initial dose and then move on to a maintenance dose of usually 200 to 400 mg daily. In people who are overweight, the SmPC says the ideal body weight should be used as the basis.^¹
According to the German S1 ophthalmology guideline (2025), the recommended maximum dose is 5.0 mg per kilogram of body weight per day. Retinal damage cannot be ruled out even then, but the risk is low.^³
A weekly schedule instead of a daily one: because there is only one tablet strength, the guideline says the dose can be adjusted over the course of the week — for example by alternating one and two tablets.
With impaired kidney or liver function the dose may need to be adjusted; impaired kidney function is also a risk factor for the retina.

However, the guideline also stresses the other side: the necessary dose is set by the treating specialists, because too low a dose can lead to more frequent flares, especially in lupus.^³ The upper limit from the ophthalmological point of view and the minimum effective dose from the rheumatological point of view therefore have to fit together.

Bring your current weight. The dose is calculated in milligrams per kilogram. If you lose a lot of weight — for example after a diet or with a weight-loss injection — you can slip above the upper limit without noticing. Tell your practice if your weight has changed significantly.

4. Taking it in everyday life

With meals, swallowed whole, with some liquid. That is what the SmPC says. Absorption into the blood does not depend on food, but your stomach tolerates the tablet better that way.^¹
A fixed time of day, a clear weekly schedule. With alternating daily doses (one or two tablets), a weekly plan or a reminder helps — otherwise the schedule starts to blur after a few weeks.
Keep a gap from antacids. Magnesium-containing antacids and kaolin can reduce absorption. The SmPC recommends a gap of at least two hours.
Missed dose: thanks to the long half-life, a single forgotten tablet is not a disaster. Do not take a double dose; simply carry on as normal. More under missed a medication.
Store it safely. Even a few tablets can be fatal for small children (section 9). The pack belongs out of reach, not in a handbag on the floor; see storing medications correctly.

Driving in the early days. According to the SmPC, headache, drowsiness, dizziness and visual disturbances can impair your reactions, especially at the start of treatment and together with alcohol or sedatives. Do not test your fitness to drive in rush-hour traffic; background in the guide medications and driving.

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5. Side effects: from the stomach to the heart

According to the SmPC, most side effects are dose-dependent. Overall, hydroxychloroquine is considered well tolerated — but you should still know about the rare risks, because they can be serious.^¹

Common and usually temporary

Stomach and bowel: nausea and abdominal pain are very common; diarrhoea, wind and vomiting are common. They often subside after a few weeks or after a dose reduction.
Headache, reduced appetite and mood swings are listed as common in the SmPC.
Skin: rash and itching are common; occasionally, dark discolouration of the skin and mucous membranes, bleaching of the hair or hair loss occur. Existing psoriasis can get worse; sun protection is worthwhile, see medications and sun.
Blurred vision due to a disturbance in focusing: common, dose-dependent and reversible — this is not the dreaded retinal damage. Deposits in the cornea, which can cause halos around lights, also regress.

Rare, but serious

Low blood sugar: according to the SmPC, severe and sometimes life-threatening hypoglycaemia with loss of consciousness has occurred — in people both with and without diabetes medication. Heart: hydroxychloroquine can prolong the QT interval on the ECG and promote heart rhythm disorders; diseases of the heart muscle have been described during long-term treatment. Mental health: depression, agitation, psychosis and suicidal behaviour have been reported, typically in the first month of treatment and even without a psychiatric history. Muscles and nerves: progressive weakness, especially of the muscles close to the trunk, can indicate a myopathy. Skin: very rarely, severe skin reactions with blisters and fever occur.^¹

When you need to act immediately. Trembling, sweating, ravenous hunger and confusion (possible low blood sugar), a racing or skipping heartbeat or fainting, new suicidal thoughts or marked changes in mood, a widespread rash with blisters and fever: seek medical help straight away. In the event of unconsciousness, a seizure or a risk of suicide, call 112 (emergency number in Germany) immediately.

6. Eye checks: retinal screening

Retinal damage caused by hydroxychloroquine (retinopathy) affects the light-sensing cells and the layer that supplies them. Once cells have been lost, it is irreversible, there is no treatment — and in advanced stages it continues to progress for years, even after stopping. The aim of screening is therefore not to prevent retinopathy, but to detect it so early that stopping in time preserves your sight.^³

How big is the risk?

According to the S1 guideline of the German Ophthalmological Society, the Professional Association of Ophthalmologists in Germany and the Retinological Society, at the recommended dose the risk is below one per cent after five years, in the range of a few per cent after ten years and around 20 per cent after 20 years.^³ So the risk is very small at first and grows markedly over the years. These figures are based on large analyses that also underpin the recommendations of the American Academy of Ophthalmology.^⁴

A higher dose than recommended — the most important factor you can influence.
A long duration of treatment, especially more than five years.
Impaired kidney function, because the drug is excreted more slowly; see chronic kidney disease.
Taking tamoxifen at the same time, as it can damage the retina itself.

The monitoring plan according to the guideline

When	What is examined	Why
In the first months of treatment	Visual acuity, visual field, back of the eye (fundus), OCT	Baseline findings; detecting and documenting any existing damage
Years 1 to 5 without risk factors	No routine screening appointments needed; immediately if vision problems occur	The risk is very low in this phase
Years 1 to 5 with risk factors	Annually, as for the baseline examination	Early detection when the risk is increased
From the 5th year of treatment	Annually, as for the baseline examination	Early detection before symptoms appear

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The most important method is optical coherence tomography (OCT), a cross-sectional scan of the retina. Fundus autofluorescence and the multifocal electroretinogram are equally suitable. According to the guideline, a suspicion should be confirmed with a second of these methods before stopping is advised. In people of Asian or African origin, the damage often starts further out and has to be looked for with a wider field of view.^³

What does not help — and what it costs. According to the guideline, an Amsler grid, a colour vision test or an ordinary photograph of the back of the eye are unsuitable for early detection: they pick up changes too late or unreliably. So a self-test at home does not replace screening. In addition, OCT and fundus autofluorescence for early detection are currently not covered by statutory health insurance.^³ Ask about the costs in advance rather than skipping screening because of them.

Symptoms appear only late. In people of European origin, the damage usually starts in a ring around the point of sharpest vision: letters "go missing" when you read, even though your visual acuity is normal. Reading problems like these or new visual disturbances are a reason for a prompt appointment, not something to leave until the next routine check. How medicines in general can affect the eyes is explained in the guide medications and eyes.

Existing retinal diseases, such as macular degeneration, are a special case. The SmPC lists pre-existing retinopathy or maculopathy as a contraindication, whereas the guideline does not regard it as an obstacle in principle, because the typical changes can usually be told apart well.^¹,³ Here the eye practice and the rheumatology practice decide together.

7. Interactions: tamoxifen, QT interval, blood sugar

Hydroxychloroquine has few interactions, but some weighty ones. Many involve medicines prescribed by a different practice — an antibiotic or an antidepressant, for example.^¹

Combination	Consequence	What to do
Tamoxifen	Both can damage the retina	Not recommended according to the SmPC; if unavoidable, annual screening from the start
QT-prolonging drugs, e.g. citalopram, azithromycin, fluoroquinolones, antipsychotics, amiodarone	Increased risk of dangerous heart rhythm disorders	Inform the prescribing practice, ECG if needed; avoid the combination where possible
Insulin and other blood sugar-lowering drugs	Stronger lowering of blood sugar, up to severe hypoglycaemia	Measure blood sugar more often; reduce the dose of diabetes medicines if needed
Magnesium-containing antacids, kaolin	Reduced absorption of hydroxychloroquine	At least 2 hours apart
Digoxin, dabigatran, ciclosporin	Higher levels of these drugs possible	Watch for side effects, check levels if needed
Methotrexate	The effect of methotrexate can be increased	A common, intended combination in rheumatoid arthritis — with the usual checks
Antiepileptics, mefloquine, bupropion	The seizure threshold falls; the effect of antiepileptics can wane	Close medical supervision in epilepsy
Rifampicin, carbamazepine, St John's wort	The effect of hydroxychloroquine can wane	Monitor effectiveness, inform the practice
Alcohol	Larger amounts strain the liver; increased drowsiness	Restraint; see medications and alcohol

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The tamoxifen combination deserves particular attention because it arises across specialist boundaries: a woman with lupus or rheumatoid arthritis develops breast cancer, the oncology practice prescribes tamoxifen — and the retinal risk rises without the eye practice ever finding out. The QT interval is similarly invisible: each drug on its own is unproblematic, but together with an antibiotic from the out-of-hours practice it can become critical. This is exactly where the brite interaction check helps: it checks every new prescription against your complete list. More background in the guide drug interactions.

8. Further checks: blood count, kidneys, heart

Besides the eyes, according to the SmPC and rheumatology therapy information, further checks are part of long-term treatment. The specific plan is set by the treating practice.^¹,⁵

Check	Why	How often (for orientation)
Blood count	Detecting rare changes in the blood count early	According to the SmPC, before starting long-term treatment and at two-monthly intervals
Kidney values (creatinine, eGFR)	Declining kidney function increases the retinal risk	Regularly, especially in older age and in lupus with kidney involvement
Liver values	Rare liver damage	Immediately if symptoms occur, otherwise according to the practice's plan
ECG	QT prolongation, heart muscle disease	In heart disease and with QT-prolonging concomitant medicines
Blood sugar	Risk of hypoglycaemia	More closely at the start in people with diabetes
Muscle strength and reflexes	Rare myopathy	Regularly during long-term treatment according to the SmPC

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The screening calendar is your job. The rheumatology practice, the eye practice and the GP practice each see only part of the picture. Note down the date you started treatment — it tells you when the fifth year begins — and enter OCT findings, kidney values and dose changes in your health history. Take the overview with you to appointments; tips in the guide preparing for a doctor's appointment.

9. Special situations: pregnancy, children, stopping

Pregnancy and breastfeeding

Here the SmPC and specialist advice diverge. For rheumatoid arthritis and lupus, the SmPC advises avoiding hydroxychloroquine in pregnancy unless the benefit outweighs the risk, and rules out breastfeeding because the drug could accumulate in the infant.^¹ Embryotox has extensive experience and considers continuing or even starting it at the usual dose to be justifiable; in lupus, continuing it during pregnancy is expressly recommended in order to reduce disease-related complications. According to Embryotox, healthy babies born at term may be breastfed at the usual dose, provided paediatric follow-up is ensured.^⁶ So if you become pregnant, do not stop hydroxychloroquine on your own, but talk to your practice straight away; more in the guide medications during pregnancy.

Children in the household

Risk of poisoning for children. According to the SmPC, small children are particularly sensitive to drugs in this group; even small amounts can be fatal. The signs of poisoning — seizures, heart rhythm disorders, circulatory failure — can set in very quickly. If a child has swallowed even a single tablet, call 112 (emergency number in Germany) immediately, do not wait for symptoms, and take the pack with you. What you should keep ready for an emergency is described in the guide medication overdose: what to do.

Other situations

Contraindications according to the SmPC: among others, glucose-6-phosphate dehydrogenase deficiency, diseases of the blood-forming system and children under six years of age or under 35 kg body weight.
Particular caution in epilepsy, porphyria, psoriasis, myasthenia gravis and heart, liver and kidney disease.
Vaccinations: according to the SmPC, routine vaccinations are not affected; only for rabies vaccination is a particular procedure recommended.

Stopping: no withdrawal, but a risk of relapse

There is no withdrawal syndrome with hydroxychloroquine. The risk lies in the underlying disease: in lupus, according to the guideline, too low a dose or stopping can lead to more frequent flares.^³ Because of the long half-life, a flare often comes only weeks to months later — and is then no longer linked to stopping. If retinopathy has been confirmed, on the other hand, the drug is stopped promptly and treatment is switched to something else. More on the planned approach under stopping medications.

10. Hydroxychloroquine experiences: what patients really ask

"My eyesight is completely normal. Why should I go for an OCT every year — and pay for it myself?"

Because "seeing normally" means nothing where this side effect is concerned. The damage starts outside the point of sharpest vision and goes unnoticed for a long time; by the time you notice it, it usually can no longer be reversed. OCT finds it years earlier. It is annoying that the examination is currently not covered by statutory health insurance — but the bill has to be weighed against an irreversible reading problem. From the fifth year onwards, it is one appointment a year.

"The ophthalmologist says my dose is too high. The rheumatologist says it is fine."

This happens because different ways of calculating are in circulation: the SmPC works with ideal body weight and a higher upper limit, the ophthalmology guideline with 5 mg per kilogram of body weight. On top of that come out-of-date weight entries in your records. Ask both practices to coordinate directly, and bring your current weight and the exact weekly dose with you. Do not reduce the dose on your own — in lupus, too low a dose can trigger flares.

"I have felt sick all the time since I started."

Stomach complaints are the most common side effect and often improve after a few weeks. Taking it with food and, after consultation, a temporarily lower dose can help. Tell your practice before you stop: because of the long half-life, quietly abandoning treatment is often only noticed at the next flare.

Tamoxifen, an antibiotic, an antidepressant — do they go together?

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FAQ: Common questions about hydroxychloroquine

How often do I need to see an eye specialist while taking hydroxychloroquine?

According to the 2025 ophthalmology guideline, a baseline examination with OCT takes place in the first few months. From the fifth year of treatment, checks are annual; with risk factors such as a high dose, impaired kidney function or tamoxifen, they are annual from the start. If you have reading problems or new visual disturbances, you should make an appointment promptly.

Can retinal damage caused by hydroxychloroquine be cured?

No, there is no treatment. In early stages the damage usually comes to a halt after stopping; in advanced stages it can continue to progress for years afterwards. That is why regular screening is so important: it is meant to find the changes before they noticeably affect your sight.

Does health insurance pay for the OCT examination?

According to the ophthalmology guideline, OCT and fundus autofluorescence for the early detection of retinal damage are currently not covered by statutory health insurance. Ask the eye practice about the costs in advance and ask your health insurer about possible reimbursement. Skipping screening is not a good way to save money.

How long does it take for hydroxychloroquine to work?

The effect builds up slowly. According to the SmPC, success can be judged after four to twelve weeks at the earliest; if there is no improvement within six months, the treatment is reconsidered. Mild side effects, on the other hand, can appear early.

Does hydroxychloroquine weaken the immune system?

Hydroxychloroquine gently dampens the autoimmune reaction and is not considered a classic immunosuppressant. According to the SmPC, routine vaccinations are not affected. However, in combination with other immunosuppressants, reactivations of hepatitis B or shingles, for example, have been reported.

Can I take hydroxychloroquine during pregnancy?

The SmPC is cautious, but the Embryotox advisory centre considers taking it at the usual dose to be justifiable and expressly recommends continuing it in lupus. Stopping can trigger flares that are risky for mother and child. Discuss a planned or existing pregnancy with your practice straight away.

What should I do if a child has swallowed hydroxychloroquine?

Call 112 (emergency number in Germany) immediately, even if the child still seems fine. In children, even small amounts can trigger life-threatening heart rhythm disorders and seizures that set in very quickly. Take the pack with you so the ambulance team knows the drug and the amount.

Sources

Summary of Product Characteristics (SmPC) for Quensyl® (hydroxychloroquine sulfate 200 mg film-coated tablets), as of March 2025, sections 4.1 to 4.9 and 5.2 — German source. fachinfo.de
Fanouriakis A et al.: EULAR recommendations for the management of systemic lupus erythematosus: 2023 update. Ann Rheum Dis 2024. ard.bmj.com
German S1 guideline on ophthalmological screening during treatment with chloroquine or hydroxychloroquine (German Ophthalmological Society, Professional Association of Ophthalmologists in Germany, Retinological Society; AWMF reg. no. 045-016, version 1, July 2025) — German source. awmf.org
Marmor MF et al.: Recommendations on Screening for Chloroquine and Hydroxychloroquine Retinopathy (2016 Revision). American Academy of Ophthalmology, Ophthalmology 2016. aao.org
German Society for Rheumatology (DGRh), Pharmacotherapy Committee: therapy information sheet on hydroxychloroquine. Accessed 2026 — German source. dgrh.de
Embryotox, Charité Berlin — German pharmacovigilance and advisory centre for embryonic toxicology: hydroxychloroquine in pregnancy and breastfeeding. Accessed 2026. embryotox.de

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Medical disclaimer: This article is for general information and does not replace medical advice, diagnosis or treatment. Do not change your dose of hydroxychloroquine on your own and do not stop it without consulting your practice — especially in lupus, this can trigger flares. Attend the recommended eye examinations, even if your sight is good. Keep the tablets out of the reach of children; if a child has swallowed tablets, call 112 (emergency number in Germany) immediately. If you have signs of low blood sugar, a racing heart, fainting or sudden changes in mood, contact a doctor straight away or, in an emergency, call 112. The choice of medicine and the dose are always set individually by the treating practice. Last updated: September 2026.