The side effects for taking hydroxychloroquine can include peeling, blistering, loosening of the skin; chest discomfort, tightness, pain; dark urine, defective color vision, breathing difficulty, fainting or dizziness; uneven, pounding, fast heartbeat; seeing, hearing, or feeling things that aren't; weakness or feeling of tiredness; inability to move your eyes; muscle or joint pain; blurred vision; hoarseness or cough; decreased urination; diarrhea; poor night vision; fever; headache; spasms or increased blinking of the eyelid; large, or hive-like swelling on the eyelid, tongue, hands, feet, face, lips, throat, legs, and sex organs; side or lower back pain; difficult or painful urination; loss of hearing; noisy breathing; irritated red eyes; severe mental or mood changes; stomach pain; red skin lesions; unusual behavior; ulcers, sores, or white spots in the mouth or on the lips; swelling in the leg, painful or swollen glands; uncontrolled twisting of the neck, arms, legs, or trunks; and some more.