Although not all of these side effects may occur, if they do occur they may need medical attention. Check with your doctor immediately if any of the following side effects occur while taking hydroxychloroquine: Incidence not known Some side effects of hydroxychloroquine may occur that usually do not need medical attention. Hydroxychloroquine can suppress appetite What does plaquenil do to the immune system P atients taking Plaquenil hydroxychloroquine, Sanofi-Aventis on a long-term basis may leave you scratching your head when it comes to coding the patient encounters. Although coding for long-term medications is not a difficult process. Taking hydroxychloroquine long-term or at high doses may cause irreversible damage to the retina of your eye. Stop taking hydroxychloroquine and call your doctor at once if you have trouble focusing, if you see light streaks or flashes in your vision, or if you notice any swelling or color changes in your eyes. Over the long term hydroxychloroquine can reduce pain, swelling and joint stiffness. If you have lupus, it may also improve the rash. It may be as long as 12 weeks before you notice the benefits. Hydroxychloroquine is often taken in combination with other drugs such as methotrexate. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. These side effects may go away during treatment as your body adjusts to the medicine. Long term use of hydroxychloroquine Continuation of long term treatment with., Side Effects of Plaquenil Hydroxychloroquine, Warnings, Uses Chloroquine gene transfection Aug 14, 2017 Long-Term Side Effects of Plaquenil for Rheumatoid Arthritis. Plaquenil is the brand name of hydroxychloroquine, a drug used to prevent or treat malaria. Plaquenil is also used for long-term treatment of autoimmune diseases such as rheumatoid arthritis RA and systemic lupus erythmatosis. Long-Term Side Effects of Plaquenil for Rheumatoid Arthritis.. Hydroxychloroquine Side-effects, uses, time to work. Hydroxychloroquine Side Effects, Dosage, Uses, and More. Originally, hydroxychloroquine was used to prevent and treat malaria and was considered very effective. Now it is generally used for rheumatoid arthritis, but it has also been shown to work well for juvenile arthritis, some lupus symptoms, and other types of autoimmune conditions. A new investigation analyzed the retinal changes over a five-year period in people with lupus and did not find clinically relevant retinal changes in the group. The study concludes that hydroxychloroquine therapy is safe for long-term use at doses 5. Taking hydroxychloroquine long-term or at high doses may cause irreversible damage to the retina of your eye. Stop taking this medicine and call your doctor at once if you have trouble focusing, if you see light streaks or flashes in your vision, or if you notice any swelling or color changes in your eyes.