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. Would chloroquine in a sickle cell patient be harmful Plaquenil and hydroxychloroquine It can reduce skin problems in lupus and prevent swelling/pain in arthritis, though it is not known exactly how the drug works. How to use Plaquenil Hydroxychloroquine is usually taken with food. For the Consumer. Applies to hydroxychloroquine oral tablet. Along with its needed effects, hydroxychloroquine the active ingredient contained in Plaquenil may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention. Side effects include irritability, headache, weakness, hair lightening or loss, stomach upset, nausea, dizziness, muscle pain, rash and itching. Rarely, hydroxychloroquine can affect the bone marrow leading to reduced white blood cells leukopenia or platelets thrombocytopenia. 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. Can hydroxychloroquine cause a lupus type rash Chronic Conditions What Is Autoimmune Disease Rash., Plaquenil Side Effects Common, Severe, Long Term - What is chloroquine phosphate used forJulia hu hydroxychloroquine A known side effect of using antimalarials long term is dark patches on the skin. The Lupus Encyclopedia Thomas Jr. 2014 says this 'One of the potential long-term side-effects of using anti-malarial medications such as hydroxychloroquine Plaquenil, chloroquine, and quinacrine is the development of dark-colored patches on the skin. Hydroxychloroquine and skin darkening Hi All. - LUPUS UK. Hydroxychloroquine Plaquenil Side Effects & Dosage for.. Hydroxychloroquine MedlinePlus Drug Information. A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including rash, itching/swelling especially of the face/tongue/throat, dizziness, trouble breathing. This is not a complete list of possible side effects. Plaquenil hydroxychloroquine is an antimalarial medication used to treat or prevent malaria, a disease caused by parasites, which enter the body through the bite of a mosquito. Plaquenil is also used to treat symptoms of rheumatoid arthritis and discoid or systemic lupus erythematosus. Hydroxychloroquine, originally used as an antimalarial agent, has beneficial effects on mucocutaneous symptoms in systemic lupus erythematosus. It is also used for the skin rash of discoid lupus erythematosus. A number of rare but serious adverse reactions can occur with its use and are usually associated with long-term therapy.