What special examinations should be periodically obtained during hydroxychloroquine (HCQ) sulfate use?

Periodic Examinations Required During Hydroxychloroquine Sulfate Use

During hydroxychloroquine (HCQ) therapy, patients should receive a baseline ophthalmologic examination within the first year of starting treatment, followed by annual screening after 5 years of use that includes automated visual fields and spectral-domain optical coherence tomography (SD-OCT). 1, 2

Ophthalmologic Monitoring Schedule

• Baseline examination: Complete ophthalmologic examination within the first year of starting HCQ to rule out underlying retinal disease 1, 2
• Initial monitoring period: If no special risk factors exist, screening can be deferred for the first 5 years of use 1
• Long-term monitoring: Annual screening should begin after 5 years of continuous use 1
• High-risk patients: More frequent screening may be needed for patients with risk factors 1, 2

Recommended Ophthalmologic Screening Tests

• Primary screening tests (both should be performed):

  • Automated visual fields focusing on central 10 degrees of retina (10-2 protocols) 1
  • Spectral-domain optical coherence tomography (SD-OCT) 1, 3

• Special considerations for East Asian patients:

  • Broader OCT (30° line scans) 1
  • Wider field tests (24-2 or 30-2 protocols) 1

• Additional tests for questionable findings:

  • Multifocal electroretinography (mfERG) 1, 3
  • Fundus autofluorescence imaging (FAF) 1, 3

Risk Factors Requiring More Vigilant Monitoring

• High daily dose (>5.0 mg/kg of actual body weight) 1, 4
• Kidney disease or reduced renal function 1, 4
• Concurrent tamoxifen use 1, 4
• Duration of use exceeding 5 years 2, 4

Laboratory Monitoring

• Annual complete blood count (CBC) to monitor for myelosuppression, including aplastic anemia, agranulocytosis, leukopenia, or thrombocytopenia 2, 5
• Annual liver function tests (LFTs) 2
• Periodic assessment of renal function, especially in patients with underlying connective tissue disorders 5

Clinical Monitoring

• Regular assessment of muscle strength and deep tendon reflexes to detect myopathy or neuropathy 5
• Monitoring for neuropsychiatric symptoms, especially within the first month of treatment 5
• Blood glucose monitoring in diabetic patients or those with symptoms of hypoglycemia 5

Important Clinical Considerations

• Retinopathy is not reversible and may progress even after discontinuation of HCQ 6, 7
• Early detection is critical as visual acuity typically remains excellent until severe stages of damage 2, 4
• Questionable test results should be repeated or validated with additional procedures before discontinuing HCQ, as it is a valuable medication for many rheumatic diseases 1
• The decision to discontinue HCQ should involve shared decision-making between the patient, prescribing physician, and eye care provider 1

Common Pitfalls to Avoid

• Relying solely on visual acuity testing, which remains normal until late stages of toxicity 4, 8
• Waiting for visible "bull's-eye" maculopathy, which represents advanced disease 1, 6
• Using ideal body weight instead of actual body weight when calculating dosage 4
• Failing to recognize that East Asian patients may present with a different pattern of retinal toxicity (pericentral rather than parafoveal) 1
• Discontinuing HCQ prematurely based on uncertain findings without confirmation 1

By following these monitoring guidelines, clinicians can help minimize the risk of irreversible retinal toxicity while allowing patients to benefit from this important therapeutic agent.