Chloroquine:
Chloroquine is an anti-malarial drug. It is used to treat chronic
inflammatory diseases, including rheumatoid arthritis and systemic lupus
erythematosus. Recently, It’s broad-spectrum antiviral activity is
identified. Chloroquine interferes with the biosynthesis of nucleic
acids and caused accumulation of toxic heme metabolite within the
parasite, thus killing them. Chloroquine inhibits the production of
interleukin-1 and the release of enzymes in the treatment of rheumatoid
arthritis. Its anti-viral mechanism of action involves inhibition of
glycosylation of SARS-CoV-2 cell receptors blocking viral entering and
increasing the pH of endosomes. Chloroquine showed in vitro inhibition
of SARS-CoV-2 (EC50 = 1.13 μM). Reports have so far shown that
chloroquine phosphate is preferred in managing of pneumonia. It
encourages virus-negative transformation and reduces illness
duration[41]. 500mg dose of Chloroquine orally
once or twice daily proved very effective[20].
Clinical trials of chloroquine phosphate should be designed in such a
way to monitor the possible side effects used by oral use.
Hydroxychloroquine:
Hydroxychloroquine has a similar mechanism of action as chloroquine.
Furthermore, Hydroxychloroquine prevents the activation of
pro-inflammatory genes. It also reduced the cytokine syndrome via
inhibition of T-cell receptors. Anti-inflammatory, as well as the
anti-viral role of hydroxychloroquine, proved very potent in combating
COVID-19. Hydroxychloroquine is safer than that of chloroquine. EC50 of
hydroxychloroquine = 6.14 μM and that of chloroquine is 23.90
μM[20]. The dose of hydroxychloroquine in COVID-19
treatment is 400 mg of loading dose twice for one day, followed by 200
mg twice daily. Dosing needed further studies. Side effects of
hydroxychloroquine include hypoglycemia, retinopathy, QTc prolongation,
and neuropsychiatric effects. However, no infant ocular toxicity is
reported in a review of 12 studies, including 588 pregnant
patients[20]. Hydroxychloroquine proved less toxic
than chloroquine, but prolonged use is still associated with severe side
effects. Considering that most patients are asymptomatic or present with
less severe symptoms, the use of dangerous drug Chloroquine and
hydroxychloroquine cannot be recommended unless they are proven
effective in treatment. Social distancing remains the top priority
measure for the prevention of COVID-19.[18]