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. Mechanism of action of hydroxychloroquine in fibromyalgia Plaquenil and irritable bowel syndrome Side Effects. Drug information provided by IBM Micromedex Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention. Plaquenil is the brand name for the prescription drug hydroxychloroquine. It's used to treat and prevent malaria infection, and to reduce symptoms and progression of autoimmune diseases such as. Hydroxychloroquine Plaquenil is considered a disease-modifying anti-rheumatic drug DMARD. It can decrease the pain and swelling of arthritis. It may prevent joint damage and reduce the risk of long-term disability. Hydroxychloroquine is in a class of medications that was first used to prevent and treat malaria. 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. Plaquenile alcohol Hydroxychloroquine Side Effects, Dosage, Uses, and More, Plaquenil Hydroxychloroquine - Side Effects, Dosage. Leflunomide hydroxychloroquineEffects of plaquenil rx on osteoarthritis Females, geriatric patients, patients with diabetes, thyroid disease, malnutrition, liver impairment, or those who drink alcohol to excess may also be at increased risk for QT prolongation. Chronic toxicity should be considered when conduction disorders bundle-branch block, AV block or biventricular hypertrophy are diagnosed. Plaquenil hydroxychloroquine sulfate dose, indications.. Hydroxychloroquine Plaquenil. Hydroxychloroquine Indications, Side Effects, Warnings.. Hydroxychloroquine is used to treat or prevent malaria, a disease caused by parasites that enter the body through the bite of a mosquito. Malaria is common in areas such as Africa, South America. Medical usesHistorySide effectsMechanism of actionResultsAdministrationRisksDiagnosisInteractionsPreventionBenefits PLAQUENIL ® hydroxychloroquine sulfate is a white or practically white, crystalline powder, freely soluble in water; practically insoluble in alcohol, chloroform, and in ether. The chemical name for hydroxychloroquine sulfate is 2-4-7-Chloro-4-quinolylaminopentylethylamino ethanol sulfate 11.