Final answer:
The most common side effect of hydroxychloroquine is gastrointestinal discomfort, which includes symptoms such as nausea, stomach cramps, and diarrhea. Retinopathy is a less common but serious side effect, particularly associated with long-term use.
Step-by-step explanation:
The most common side effect of hydroxychloroquine, which is used to treat symptoms of autoimmune diseases like systemic lupus erythematosus (SLE), is gastrointestinal discomfort. Patients may experience side effects such as nausea, stomach cramps, and diarrhea. Hydroxychloroquine is also known for its potential to cause retinopathy, although this is a less common albeit more serious side effect that can occur with long-term use.
Due to its anti-inflammatory properties, hydroxychloroquine is used to manage symptoms like mild arthralgias and rash in lupus patients, among other conditions. The patient's rheumatologist must closely monitor for these side effects, especially with long-term therapy.