Final answer:
Plaquenil (hydroxychloroquine) is used to treat malaria, rheumatoid arthritis, and lupus erythematosus.
Step-by-step explanation:
The use of Plaquenil (hydroxychloroquine) includes treating multiple conditions such as malaria, rheumatoid arthritis, and lupus erythematosus. Plaquenil is an antimalarial drug that can also be used to manage the symptoms of autoimmune diseases like rheumatoid arthritis and lupus erythematosus.
For malaria treatment, Plaquenil is used to kill the malaria parasites that enter the body through mosquito bites. In rheumatoid arthritis and lupus erythematosus, Plaquenil helps to reduce joint pain, inflammation, and other symptoms.