Some patients who take antimalarial medications may find that their skin is more sensitive to sunlight. Special precautions may be necessary to ensure that skin is not sunburned during this time. In addition, some patients who take antimalarial agents for four months or longer find that their skin temporarily takes on a bluish-gray to black tint. This typically affects the shins, face, palate or nail beds. Progressive bleaching of the hair roots of the scalp or face also may occur. These effects are reversible with cessation of therapy.

Other side effects associated with antimalarials include dry skin (xerosis), itchy skin (pruritus), skin rash, stomach upset, loss of appetite, nausea, vomiting, diarrhea, headache, nervousness, irritability, dizziness, mild hair loss and difficulty sleeping. 

Patients with psoriasis may experience severe flare-ups while taking antimalarial drugs. Antimalarial drugs belong to a class of drugs known as disease-modifying antirheumatic drugs (DMARDs) and may be prescribed to help minimize joint damage that occurs in psoriatic arthritis and rheumatoid arthritis. Again, these drugs may cause severe psoriasis flare-ups in people who take them to treat psoriatic arthritis. Hydroxychloroquine is less likely to cause these flare-ups than other antimalarials.

Patients who have been treated with antimalarial agents may feel very weak and tired afterward. It may take a few weeks before a patient recovers completely.

Individuals experiencing severe or persistent side effects should contact their physician. Patients should contact their physician immediately if any of the following signs or symptoms occur:

• Vision changes (e.g., blurred vision, difficulty reading, light flashes or streaks)
  
  
• Sensitivity to light
  
  
• Eye pain
  
  
• Hearing loss
  
  
• Ringing in the ears
  
  
• Muscle weakness
  
  
• Unusual tiredness
  
  
• Unusual bleeding or bruising of the skin
  
  
• Mood or other mental changes
  
  
• Irregular heartbeat
  
  
• Drowsiness
  
  
• Seizures

These signs and symptoms may signal a serious adverse reaction, such as damage to the retina (the tissue that lines the inside of the eye) or myopathy (a disorder or disease of the skeletal muscles).