These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. How to prescribe chloroquine Hydroxychloroquine to treat hair loss What are the side effects of hydroxychloroquine Plaquenil? Side effects include irritability, headache, weakness, hair lightening or loss, stomach upset, nausea, dizziness, muscle pain, rash and itching. However, dose is usually not more than 800 mg for the first dose and not more than 400 mg for the next doses. For treatment of arthritis Adults—At first, 400 to 600 milligrams mg taken as a single dose or in two divided doses once a day. Then, 200 to 400 mg taken as a single dose or in two divided doses once a day. Hydroxychloroquine SULFATE. Uses. Hydroxychloroquine is used to prevent or treat malaria infections caused by mosquito bites. It does not work against certain types of. Side Effects. Precautions. Interactions. If you notice any other effects, check with your healthcare professional. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them: Other side effects not listed may also occur in some patients. Plaquenil 200 mg tablets side effects Plaquenil Side Effects - GoodRx, Hydroxychloroquine Oral Route Proper Use - Mayo Clinic Plaquenil sunburn Common side effects may include headache, dizziness, ringing in your ears; nausea, vomiting, stomach pain; loss of appetite, weight loss; mood changes, feeling nervous or irritable; skin rash or itching; or. hair loss. Plaquenil, Plaquenil Sulfate, Quineprox.. Hydroxychloroquine Oral Uses, Side Effects, Interactions.. Side Effects of Plaquenil Hydroxychloroquine, Warnings, Uses. Hydroxychloroquine may not prevent malaria in all cases. If you experience fever or other symptoms of illness, seek immediate medical attention. You may need a different medication. Avoid exposure to mosquitoes. See also Notes section. SIDE EFFECTS Nausea, stomach cramps, loss of appetite, diarrhea, dizziness, or headache may occur. If any of these effects persist or worsen, notify your doctor or pharmacist promptly. Plaquenil side effects Get emergency medical help if you have signs of an allergic reaction to Plaquenil hives; difficulty breathing; swelling of your face, lips, tongue, or throat. Taking Plaquenil long-term or at high doses may cause irreversible damage to the retina of your eye. The most common side effects are nausea and diarrhea, which often improve with time. Less common side effects include rash, changes in skin pigment such as darkening or dark spots, hair changes, and muscle weakness.