Can plaquenil (hydroxychloroquine) give you a heavy feeling?

Plaquenil (hydroxychloroquine): Plaquenil (hydroxychloroquine) has many side effects. Some common ones include dizziness, abdominal pain, headache, nausea, diarrhea, itching, and sensitiviy to sun. More serious side effects which are more rare include certain types of anemia, muscle pain, and liver problems, among others. Despite the fact that what you describe is not officially under it's side effect profile, it still could be causing your symptoms.