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Hydroxychloroquine (Plaquenil)

Antimalarial treatment for autoimmune diseases such as rheumatoid arthritis and systemic lupus erythematosus.

Considered a disease modifying anti-rheumatic drug (DMARD).

Aids in preventing joint damage and reduces long-term disability from rheumatoid arthritis.

Can be used to prevent or treat malaria, but is not effective against chloroquine resistant malaria.

Can reduce skin manifestations from lupus erythematosus.

May be used for Q fever endocarditis.

Can cause Stevens-Johnson and toxic epidermal necrolysis.

Hydroxychloroquine in patients with rheumatoid arthritis reduced the risk of incident diabetes (Wasco MC et al).

Use in primary Sjogren’s syndrome compared to placebo does not improve symptoms during 24 weeks of treatment (JOQUER Trial).

Many patients at high risk for macular disease associated with the use of hydroxychloroquine do not undergo routine monitoring.

It is recommended that patients be screened for baseline eye examination at the start of the drug therapy and then annual screenings begin after five years of use.

The overall prevalence of retinopathy with the long term use is close to 7 1/2%.

The most critical factor for the development of retinal toxicity is daily use, with the risk relatively low when the drug intake is kept below 5 mg per kilogram of actual body weight.

The duration of use is highly significant for toxicity, and the risk increases markedly after 10 years of use.

Following screening and if the patient is free of retinal toxicity, the annual increase risk of developing toxicity witj daily intake less than 5 mg per kilogram is 1% for the first 10 years and under 4% after 20 years of use.

Additional risk factors include renal disease as the drug is predominantly excreted by the kidneys.

Increased risk with concomitant use of tamoxifen, increasing risk 5-fold.

Damage to the periphery of the macula is more common in patients of Asian ancestry.

No treatment presently exists for hydroxychloroquine retinopathy.

The risk of visual loss correlates closely with the amount of retinal damage at the time of diagnosis.

If a patient develops a visible bull’s-eye maculopathy hey are at high risk of losing reading vision, otherwise risk is minimal when toxicity diagnosed in early stage.

If retinal toxicity is documented the drug is discontinued.

Use in Covid-19 was not associated with either a greatly lowered or an increased risk of intubation or death.

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