QHow should I dose hydroxychloroquine in my patients who need it and what monitoring is needed? What potential side effects should I discuss with my patients?

Medically reviewed on 6.1.2023 by Mark Lebwohl, MD

Hydroxychloroquine has been utilized in dermatology to treat many conditions from lupus to sarcoidosis to lichen planus due to its unique immunomodulatory properties and low adverse event profile.

Standard dosages have ranged from 200mg to 400mg a day. In the past, recommendations were that patients could be dosed up to 6.5 mg/kg of their ideal body weight per a day (although not to exceed 400mg/day), but there has been a huge movement to lower this after a recent study examining the risk for HCQ-induced retinopathy found that optimal doses would actually be less than or equal to 5.0mg/kg of actual body weight.

Because hydroxychloroquine has a long half-life, alternate-day dosing can be used to achieve an average of the recommended daily dose.

For instance, if my patient weighs 132 lbs (60kg), an optimal dose would be 300 mg a day. Since the pills come as 200mg tablets, I would have her alternate 200mg one day with 200 mg BID (total of 400mg) the next day for an average daily dose of 300mg. 

As far as side effects, retinopathy is one of the things we most worry about in our HCQ patients, and the most critical risk factor is the daily dose. Those exceeding 5mg/kg of actual body weight daily dosing had a 10% retinopathy risk within 10 years and around 40% after 20 years. But those taking just 4-5mg/kg daily had less than a 2% risk within 10 years and 20% risk after 20 years. Risk is low during the first 5 years but increases significantly after that. The American Academy of Ophthalmology recommends that all patients on hydroxychloroquine without major risk factors receive a baseline ophthalmologic examination as well as annual screenings after 5 years of use. Major risk factors include renal disease, preexisting maculopathy, and tamoxifen use.  

Common adverse effects of HCQ include GI symptoms like nausea, vomiting, and diarrhea. These were usually transient, however. Cutaneous blue-gray hyperpigmentation is also relatively common, occurring in up to 25% of patients. Most of the patients in one study evaluating this reported the lesions were preceded by ecchymosis, suggesting easy bruising might predispose these patients to HCQ-induced hyperpigmentation.

Hemolytic anemia has occurred in patients with G6PD deficiency, but because hemolysis doesn’t usually occur at the recommended HCQ doses for dermatologic conditions, routine G6PD-deficiency testing is not recommended.

Baseline and periodic CBCs and CMPs are recommended, however, because rare reports of agranulocytosis and HCQ-induced hepatotoxicity have occurred. Lastly this medication may be used in pregnancy and does not appear to be teratogenic based on human data.

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References:

1. Anthony P Fernandez. Updated recommendations on the use of hydroxychloroquine in dermatologic practice. Journal of the American Academy of Dermatology. 2017 June.
2. ACR, AAD, RDS, and AAO 2020 Joint Statement on Hydroxychloroquine Use with Respect to Retinal Toxicity