Plaquenil Update
The antimalarials—Aralen (chloroquine, Sanofi) and Plaquenil
(hydroxychloroquine, Sanofi)—are widely used in rheumatologic
care, particularly for rheumatoid arthritis and systemic lupus
erythematosus. Since prescribing doctors are generally aware
of the retinotoxic potential of these drugs, patients are usually
requested to see an eye doctor for baseline evaluation and
follow-up surveillance.
 Most patients are placed on Plaquenil, the slightly less toxic
of the two. The usual dosage is two 200mg tablets per day.
This is generally a “safe” dose for patients having a lean
body weight of at least 135 lbs. The generally-regarded safe
dosage is 6.5mg/kg/qd, thus the 135 lb. safety threshold. (See
“Resources for Excessive Dosing.”) When a person’s lean body
weight is less than 135 lbs., the prescribing doctor should
consider reducing the total daily dose. In patients weighing
less than 135 lbs., it may require the gentle counsel of the
eye doctor to bring this touchy issue to the prescribing doctor’s
attention. Just as many eye doctors still use timolol 0.5%
bid, so too do many rheumatologists continue to prescribe Plaquenil
at 200mg bid—regardless of the patient’s lean body weight.
We all need to become precise prescribers.
Evaluating the Plaquenil Patient. The literature discusses a
variety of approaches in assessing patients sent in for Plaquenil
evaluations. In keeping with our modus operandi[ITAL] of clinical
simplicity, here’s our protocol. It’s as simple as 1-2-3.
- Best visual acuity.
- Dilated ophthalmoscopic examination of the macular and paramacular
tissues.
- Zeiss-Humphrey visual field 10-2 testing (using standard white
stimulus).
Posterior pole photodocumentation is optional if the macular
tissues are completely normal. If the macular tissues are not
completely normal at baseline, obtain fundus photography in
order to maximize monitoring for any changes that may occur
in these tissues in the future. In the event of suspicious
RPE findings (or changes), fluorescein angiography can be helpful.
Frequency of Follow-up. This is a difficult call, and is commonly
influenced by the number of years of Plaquenil exposure. It
is also dependent, to some degree, on how the prescribing doctor
has portrayed the risk of ocular side effects to the patient.
 For
newly treated patients with normal baseline findings and weights
well above 135 lbs., we recommend annual visits. For patients
close to the 135-lb. threshold, perhaps rechecking them every
six months is more appropriate; and we prefer to see patients
on 400mg qd of Plaquenil who weigh less than 135 lbs. every four
to six months. Obviously, the less the patient weighs (below
135 lbs.), the closer we tend to space the follow-up visits.
We do all we possibly can to get the prescribing physician to
reduce therapy in these situations. As noted above, there is
an inverse relationship between the patient’s weight (below 135
lbs.) and our persistence in educating and encouraging the prescribing
physician to reduce the patient’s daily dose of Plaquenil. Our
primary approach here is to send the doctor copies of  authoritative
articles supporting our recommendation.
It is always a challenge for us to make clinical care simple
because of the numerous confounding variables, such as the
patient’s anxiety level, status of the macular tissues at baseline,
expectations of the referring physician, years of cumulative
exposure, dosage, weight, etc. In almost all clinical circumstances,
patient management must be individualized.
In all of our years of clinical practice, we have seen a total
of only four patients who demonstrated maculopathy, and all four
had been chronically overdosed for several years. We have seen
no cases of toxicity when the 6.5mg/kg/qd threshold was honored;
however, in biological systems, there are no absolutes.
Literature References
We use these articles to help educate and motivate “over-treating”
physicians:
- Marmor MF, Carr RE, Easterbrook M, et al. Recommendations
on screening for chloroquine and hydroxychloroquine retinopathy.
Ophthalmology 2002 Jul;109(7):1377-82.
- Browning DJ. Hydroxychloroquine and chloroquine retinopathy:
screening for drug toxicity. Am J Ophthalmol 2002 May;133(5):649-56.
- Easterbrook M. Defining ideal body weight. (Letter to the
editor). Am J Ophthalmol 2002 Dec;134(6):935.
Plaquenil Form (.pdf file)
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