COVID-19: Chloroquine and hydroxychloroquine research
Pan American Health Organization
MetadataShow full item record
In some countries in the Americas, chloroquine or hydroxychloroquine is readily available, in some cases as an over-the-counter medicine. National authorities should take measures to control the use of these medicines and prevent self-medication. The use of chloroquine and/or hydroxychloroquine outside of current guidelines and recommendations may result in adverse effects, including serious illness and death, and have a negative impact on other diseases where there is proven benefit. Public health authorities are urged to prioritize resources on those interventions that are currently recommended for standard of care. There is currently a lack of strong evidence with strong trial design that this medication (chloroquine or hydroxychloroquine) works for COVID-19 patients. The former is used to prevent and treat malaria while the later (trade name Plaquenil) was first used to prevent and treat malaria, it is also used to treat rheumatoid arthritis, some symptoms of lupus erythematosis, childhood arthritis (or juvenile idiopathic arthritis) and other autoimmune diseases. The body of evidence thus far has been largely in vitro, and methodological quality from the body of evidence is sub-optimal, and the studies have been poorly reported and largely confounded. Moreover, the recently emerging in vivo study evidence is thin and based on 2 studies, one of which is inconclusive (China) and the others (France) alludes to benefit but have very small sample sizes, small event numbers, sub-optimal methodology, and lack the depth of detail needed for us to draw any definitive conclusion on effectiveness (see extended details below of the recently emerging in vivo evidence). Studies have been judged to be at high risk of biased estimates after critical appraisal using relevant tools. The French research particularly (of hydroxychloroquine and azithromycin), which has garnered media attention is not the type of robust, high-quality, comparative effectiveness randomized controlled trial evidence that is needed to draw definitive conclusions on benefits (and harms). Multiple clinical trials are underway to strengthen the data and better characterize effectiveness and PAHO is monitoring the situation carefully on a day to day basis. As such, while there is currently a lack of evidence for efficacy of pharmacological treatments, PAHO will immediately let countries know if/as that changes. At the same time, some are using medications in compassionate use settings/clinical trials. Moreover, compassionate use is based on the assumption that a medicine produces more benefit than harm. There is a concern of massive purchasing and possible shortages of these medicines (both chloroquine and hydroxychloroquine), which can take away from other disease programs where it is used in effective indications e.g. rheumatoid arthritis, lupus, childhood arthritis, and other autoimmune diseases. Care must be exercised in extrapolating in vitro results to in vivo, and potential side effects, toxicities and interactions with other drugs must remain a key consideration. Moreover, evidence seems to suggest that chloroquine/ hydroxycloroquine have a direct role in the electrophysiology properties of the heart. Until the COVID-19 clinical trial evidence that rules out harm in this group of patients is available, then caution is urged in considering any use.