====== Chloroquine and Hydroxychloroquine Screening Procedures ======

===== Risk =====
  * Risk increases in the following:
    * After 5 years of use
    * Hydroxycholoroquine Daily dose >5.0mg/kg real weight
    * Cholorquine Daily dose >2.3 mg/kg real weight
    * Renal disease- subnormal glomerular filtration rate
    * Tamoxifen use
    * Preexisting macular disease
  * Risk may be higher than previously believed as more sensitive testing employed (OCT, MERG)

===== Toxicity =====
  * Irreversible Toxicity as evidenced by perimacular retinal thinning, photoreceptor and RPE loss
  * Early signs are loss of outer segment structural lines and increased parafoveal autofluorescence

===== Timeline =====
  * Baseline Examination within first year of use
  * Annual Screening after 5 years of use if on acceptable doses without other risk factors
===== Recommended Screening Procedures =====
=== Ocular Exam ===
  * Dilated Retinal Exam (low sensitivity)
=== Automated Visual Field ===
  * White 10-2
  * Interpret with a low threshold for abnormality
  * Retest if abnormalities appear

=== One or More Objective Tests (abnormalities may be before field loss) ===
  * SD-OCT
    * Cross section of macula
    * localized thinning of parafoveal region especially the outer-segments and RPE structural lines
    * loss of the inner-/outer-segment line may be early sign
    * {{:oct_plaquenil_toxicity.png?400|}}
  * mfERG
    * Especially in suspicious or unreliable visual field loss
    * Paracentral voltage reduction
  * Fundus Autofluorescence
    * Increased autofluorescence possibly from accumulation of outersegment debris
    * {{::fundus_autofluorescence_plaquenil.png?300 |}}

===== Tests NOT recommended for screening =====
  * Fundus photography
  * Time-Domain OCT
  * Fluorescein Angiography- not proved to be more senstive than other tests
  * Full-field ERG- may be useful in those with manifest toxicity to evaluate degree of damage
  * Amsler grid
  * EOG

Source:[[http://www.aaojournal.org/article/S0161-6420(16)00201-3/pdf|Ophthalmology 2016:123:1386-1394]]

{{tag>drugs jia}}