Rheumatoid arthritis (RA) is a chronic, inflammatory disease of the joints which results in damage to the cartilage and bone.
RA is often treated with Plaquenil. It’s considered a very safe medication, however, Plaquenil (hydroxychloroquine) can affect your eyes. If you’ve been prescribed the drug, here’s what you need to know.
The prevalence of RA is estimated to be around 1%. Individuals usually present with bilateral arthritis in the small joints of the hands and feet, morning stiffness, fatigue, malaise, weight loss, and low-grade fever. RA may also affect the elbows, shoulders, spine, knees, and jaw. The symptoms can “flare” at any time due to stress, environmental factors, increased activity, or when medications are stopped.
The exact cause of RA is unknown but thought to be a combination of environmental and genetic factors. Increasing age, female sex, family history, smoking, obesity, and individuals with either gum disease or lung diseases are at a greater risk of developing the disease.
Immune cells cause inflammation in the synovial lining, which is the joint’s lining. Chronic inflammation leads to thickening of the synovium, which results in pain, redness, and warmth. Over time, the synovium destroys the bone and cartilage, resulting in changes to the joint structure and weakness of the surrounding muscles, ligaments, and tendons that support and stabilize the joint.
How does Plaquenil work?
Hydroxychloroquine (Plaquenil) and chloroquine are both antimalaria drugs used to treat autoimmune, inflammatory rheumatoid diseases like rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE).
Plaquenil is safe, cost-effective, and one of the first lines of treatment. Despite its common usage, the way it works is not quite understood. It is thought to work on several parts of the immune system, with the common endpoint of reducing cytokine production and release, which leads to inflammation.
Antimalarial drugs have been used for over 400 years since quinine was first discovered in the bark of a cinchona tree and was used to treat Plasmodium falciparum infections. Quinine had many side effects like gastrointestinal and skin complications, retinopathy, cardiotoxicity, and myopathy.
The discovery of hydroxychloroquine (HCQ) was vital because it was effective but with fewer side effects. Soldiers began using the medication during WW2 as a prevention for both rashes and inflammatory arthritis.
Besides RA and Lupus, the drug is being used as a potential therapy for many other conditions like COVID‐19, cancers, diabetes type I and II, multiple sclerosis, and myocardial infarction. HCQ is taken by mouth and is distributed through the body including the muscles, liver, spleen, lungs, kidneys, pituitary, and adrenal glands.
HCQ treatment decreases the symptoms of RA by suppressing the immune system. The drug is often used in combination with steroids for an additive effect. Furthermore, the medication has demonstrated an effect on preventing cartilage degradation which leads to joint destruction.
How does Plaquenil affect the eyes?
Overall, Plaquenil is a very safe medication. It is so safe that it can be used throughout pregnancy.
Plaquenil can affect the central part of the retina called the macula resulting in Bull’s eye maculopathy. Though the mechanism of toxicity is not understood, studies indicate it may be because the drug molecule binds to melanin in the retinal pigment epithelium (RPE), a layer of the retina.
The binding leads to disruption and damage to the photoreceptors and the outer nuclear and plexiform layer, but spares the center of the macula, called the fovea, resulting in the “Bull’s eye” appearance in the late stage of the disease. Bull’s-eye maculopathy looks like rings of lighter-colored damage around a darker area of the macula. The macula may look like circular bands of different shades of color.
Vision changes are not apparent during the early stages of drug toxicity, but over time, the patient could experience retina damage and central vision loss. Initially, the risk of toxicity was thought to be less than 1% after long-term use but may increase with treatment time, resulting in a 20% prevalence after 20 years. Current research demonstrates the toxicity can continue even after discontinuing the drug.
What to expect from an eye exam when taking Plaquenil
When you start Plaquenil, you should have a comprehensive eye exam with dilation. Some eye care providers may also have you return for pictures of your retina for documentation.
You will also be asked to complete specialized testing including an OCT and VF. Optical coherence tomography (OCT) is noninvasive imaging that uses reflected light to create images of the back of your eye, called the retina.
The testing can be used to look specifically at the various layers of the macula, the central area of the retina. The OCT is a simple test for the patient. They will be asked to look through the OCT device at a snowflake. The test is completed within seconds. Upon test completion, their doctor is provided with a printout with detailed results. The OCT can detect changes before visible clinical changes.
A 10-2 visual field (VF) screening test is also important for detecting early retina changes. The VF tests show the patient points of light in the central 10 degrees of the retina. The test can detect sensitive paracentral defects. Patients will be asked to look at a central cross within the device and push a button when they see the lights. The doctor will then be provided with a printout to look for change.
Most rheumatologists will want you to see your eye doctor every year to complete your testing. Annual follow-up is key to ensuring the continual safety of the drug and the protection of your retina from retinopathy.
Rheumatoid arthritis can be effectively treated with Plaquenil. Adverse side effects are rare and retina damage can be prevented if monitored. Routine Plaquenil screening typically includes a dilated eye exam, visual field, and an OCT to look for the early signs of Bull’s eye maculopathy. Your rheumatologist, together with your eye doctor will monitor the condition.
