Causality assessment · Causality: well established

Hydroxychloroquine and Retinopathy: is the FAERS signal real?

n=290 co-reports · PRR 23.7 · ROR 23.8

Hydroxychloroquine side-effect profile All assessments See in the full list

A written Bradford Hill assessment of one drug–event pair. The grade is a judgement about the signal, not a statement that this drug causes this event in any one person; FAERS counts are reports, not rates.

Causality: well established

Hydroxychloroquine ↔ Retinopathy

n=290 co-reports · PRR 23.7 · ROR 23.8

Hydroxychloroquine, a mainstay of treatment for lupus and rheumatoid arthritis, can cause a cumulative-dose retinal toxicity that, if not caught, becomes irreversible and can progress even after the drug is stopped. The risk is driven by daily dose per kilogram of body weight and by duration of use, and ophthalmology has moved to annual screening with sensitive imaging (optical coherence tomography and visual fields) precisely because early changes are reversible while late damage is not. Age and kidney disease raise the risk, and standard thresholds for maximum daily dose and screening intervals are now embedded in professional guidelines and the labeling. This is a model example of a chronic, cumulative-dose-dependent toxicity where the “biological gradient” is central to how the drug is monitored.

Regulatory basis: hydroxychloroquine prescribing information (ocular toxicity warning). American Academy of Ophthalmology screening guidelines (dose and interval thresholds).

Bradford Hill viewpoint	Status	Note
Temporality (necessary)	met	Damage accumulates over years of exposure
Strength	met	PRR 24 for a slowly developing, under-reported outcome
Consistency	met	Replicated across large rheumatology cohorts
Specificity	partial	Shared with the related drug chloroquine
Biological gradient	met	Strongly cumulative dose- and duration-dependent — the basis for screening thresholds
Plausibility	met	Drug accumulates in retinal pigment epithelium and causes characteristic photoreceptor loss
Coherence	met	Coheres with the AAO screening guidance
Experiment	partial	Early detection reverses the trend; no randomized exposure trial is feasible
Analogy	met	Analogous to chloroquine retinopathy (the historical index case)

This page's own qualitative read, not an automated/citation-gated assessment.

✗ No ClinicalTrials.gov results-posting trial in the top search hits for hydroxychloroquine captured retinopathy as a tracked adverse event. Retinal toxicity develops over many years of therapy, far outside ordinary trial follow-up, and is detected by dedicated ophthalmic imaging rather than coded as a trial endpoint — so its evidence base is long-term cohort data and ophthalmology screening guidelines.