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. When does plaquenil start working Mechanism of action hydroxychloroquine Chloroquine er derived vaculation 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. Remember. Hydroxychloroquine Plaquenil is used to treat malaria, lupus, and rheumatoid arthritis. Learn about side effects, warnings, dosage, and more. Check with your doctor immediately if any of the following side effects occur while taking hydroxychloroquine Incidence not known Blistering, peeling, loosening of the skin 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. Plaquenil medication side effects Plaquenil, Plaquenil Sulfate, Quineprox hydroxychloroquine Uses, Side., Hydroxychloroquine Side Effects, Dosage, Uses, and More Icd for starting plaquenil medicationPlaquenil made from what rootPlaquenil and retinal damageConditions to take plaquenilPhotodegradation of chloroquine phosphate Check with your doctor immediately if any of the following side effects occur Incidence not known. Blistering, peeling, loosening of the skin blurred vision or other vision changes chest discomfort, pain, or tightness cough or hoarseness dark urine decreased urination defective color vision diarrhea difficulty breathing Hydroxychloroquine Oral Route Side Effects - Mayo Clinic. Hydroxychloroquine Side Effects -. Plaquenil Drug and Medication User Reviews on RxList. What Are Side Effects of Plaquenil? nausea, vomiting, stomach pain or cramps, loss of appetite, weight loss, diarrhea, dizziness, spinning sensation, headache, ringing in your ears, Before taking hydroxychloroquine, tell your doctor and pharmacist if you are allergic to hydroxychloroquine, chloroquine Aralen, primaquine, or any other drugs. tell your doctor and pharmacist what prescription and nonprescription drugs you are taking, especially acetaminophen Tylenol, others, digoxin Lanoxin. 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. Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects.