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Coronavirus (COVID-19) and Hydroxychloroquine

Coronavirus (COVID-19) and Hydroxychloroquine

A Look on Coronavirus (COVID-19) and Hydroxychloroquine.

Hydroxychloroquine and Chloroquine has long been used in Rheumatoid Arthritis as an immunomodulating agents and Malaria for their anti-infective properties. These are now being repurposed by themselves or in combination with Azithromycin and presented as a therapeutic option to ameliorate the new Coronavirus (COVID-19) infection. The evidence base that they really work is weak but in desert of despair looks like an oasis, but is it just a mirage? The dilemma was amply on display when President Trump advice appeared to be at odds with his chief medical officer last weekend.

In absence of an alternative it’s one of the best options we have got. But there are other options under trial too and showing promise. Randomised controlled trial will rapidly provide us with the best evidence for what would be our best foot forward for the masses yet to come. Unfortunately for individual trial participants now that will not provide much solace.

Eye doctors have significant past experience with these drugs. We screen for a toxic maculopathy which can cause irreversible visual loss if not detected early. Hydroxychloroquine is much safer in this respect compared to its cousin Chloroquine. In Africa pill popping at the first sign of a fever to stave off Malaria early is relatively common leading to excessive drug loads that one would not expect if used appropriately. Some of the dosing with Hydroxychloroquine recommended for COVID-19 treatment is 30-50% higher than for Malaria prophylaxis treatment and Rheumatoid arthritis respectively.

hydroxychloroquine toxicity graph
hydroxychloroquine therapy graph

In addition the combination of hydroxychloroquine and Azithromycin can caused prolongation of the QT in heart ECGs. The risk of arrhythmias is already significant in severe COVID-19 infection. Again medical supervision when used in mild/early disease may be important.

Earlier this week in Brisbane, Australia, I had a rheumatoid patient who went to three local suburban pharmacies before she could fill her regular hydroxychloroquine script. If the public begin to pill pop at the sniff of a fever in case they have the new Coronavirus (COVID-19) then the calculations based on a 7.5% risk of ocular toxicity after 5 years with hydrochloroquine are out the window.

Good data from RCTs and treatment under appropriate supervision remain key to both general and ocular health. In the interim wash your hands, avoid touching your face, practice social distancing and stay safe.

See what EyesMatter are doing in our clinics to help stop the spread of Coronavirus (COVID-19).

  1. Vincent, M.J., Bergeron, E., Benjannet, S. et al. Chloroquine is a potent inhibitor of SARS coronavirus infection and spread. Virol J 2, 69 (2005).
  4. 24 Melles RB, Marmor MF. The risk of toxic retinopathy in patients on long-term hydroxychloroquinetherapy. JAMA Ophthalmology. 2014;132(12):1453-60.