Hydroxychloroquine is a quinoline medication that treats or prevents malaria. It is not effective against all malaria strains. It is also used to treat rheumatoid arthritis symptoms and discoid or systemic lupus erythematosus symptoms. Hydroxychloroquine is not approved for use in patients under age 18.

Take for full prescribed length of time, even if malaria symptoms improve. Tell doctor if lupus or arthritis symptoms do not improve after 6 months. Take with meal or glass of milk. Adhere to dosing schedule as prescribed. If dosing is weekly, choose the same day of the week. Hydroxychloroquine is not 100% effective, so take other steps to prevent malaria, such as using insect repellents and mosquito netting.

May cause irreversible retina damage. Overdose can be fatal, so get emergency attention if you think you have taken too much hydroxychloroquine. Inform doctor of all known medical conditions and medications, as this drug may interact with a number of drugs and conditions, including other malaria medications, antivirals, antibiotics, antifungals, antidepressants, and birth control. Inform doctor if you are pregnant. Avoid taking antacid or Kaopectate within 4 hours before/after hydroxychloroquine.

Cease use and inform doctor immediately if you experience vision problems or eye irregularities. Get emergency attention immediately if you experience an allergic reaction. Call doctor at once if you experience serious effects such as: headache with chest pain and dizziness, pounding heartbeat, slow/weak pulse, muscle weakness, symptoms of low blood sugar or low blood cell count. Other common side effects include: ringing in ears, headache, dizziness, nausea and vomiting, weight loss, appetite loss, mood changes, hair loss, rash/itching.