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. Chloroquine phosphate brooklynella Mosquitos and plaquenil Plaquenil hydroxychloroquine belongs to a group of medicines called quinolines. Plaquenil 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, and Southern Asia. 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. For patients taking hydroxychloroquine to prevent malaria Your doctor may want you to start taking this medicine 1 to 2 weeks before you travel to an area where there is a chance of getting malaria. This will help you to see how you react 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. These side effects may go away during treatment as your body adjusts to the medicine. Splitting hydroxychloroquine Plaquenil Drug and Medication User Reviews on RxList, Hydroxychloroquine Plaquenil Cialis plaquenil Hydroxychloroquine sulfate tablets are indicated for the treatment of uncomplicated malaria due to P. falciparum, P. malariae, P. ovale, and P. vivax. Hydroxychloroquine sulfate tablets are indicated for the prophylaxis of malaria in geographic areas where chloroquine resistance is not reported. Limitations of Use in Malaria Hydroxychloroquine Tablets - FDA prescribing information, side effects.. Hydroxychloroquine Oral Route Proper Use - Mayo Clinic. Side Effects of Plaquenil Hydroxychloroquine, Warnings, Uses. Don’t split your pills with a knife. Studies show that doing so too often leads to unequal halves. Pills should only be split in half, not into smaller portions, such as thirds or quarters. The easiest pills to split are relatively flat round ones with a scored center. Recommendations on Screening for Chloroquine and Hydroxychloroquine Retinopathy Retinal toxicity from chloroquine CQ and its analogue, hydroxychloroquine HCQ, has been recognized for many years. Chloroquine toxicity remains a problem in many parts of the world, but is seen less frequently in the United States where the drug largely has been replaced by HCQ. Hydroxychloroquine oral tablet is available as a brand-name drug and a generic drug. Brand name Plaquenil. Hydroxychloroquine comes only as a tablet you take by mouth. Hydroxychloroquine is used to treat malaria, lupus erythematosus, and rheumatoid arthritis.