Chloroquine phosphate, when used without a prescription and supervision of a healthcare provider, can cause serious health consequences, including death. Clinicians and public health officials should discourage the public from misusing non-pharmaceutical chloroquine phosphate (a chemical used in home aquariums). Clinicians should advise patients and the public that chloroquine, and the related compound hydroxychloroquine, should be used only under the supervision of a healthcare provider as prescribed medications.
The Centers for Disease Control and Prevention (CDC) has become aware of two individuals who ingested non-pharmaceutical chloroquine phosphate, a chemical for aquarium use that is commercially available for purchase at stores and through internet websites. One of the individuals died shortly after arrival to the hospital. The second individual was critically ill with severe gastrointestinal symptoms and cardiac conduction abnormalities. Upon recovery, the surviving individual reported to the media that they ingested the product to prevent infection with SARS-CoV-2, which causes coronavirus disease 2019 (COVID-19), after seeing information on the medical use of chloroquine on television. The product in their possession was in powder form inside a 2.2-lb. container and labeled “for Ornamental Fish Use Only”. CDC is also aware of unconfirmed media reports that these commercially available aquarium-use chemicals may be out of stock due to potential increased demand by the public.
At this time, there are no routinely available pharmaceutical products that are FDA-approved for the prevention or treatment of COVID-19. Pharmaceutical chloroquine phosphate and hydroxychloroquine sulfate are approved by the US Food and Drug Administration (FDA) to treat specific medical conditions, such as malaria, lupus, and rheumatoid arthritis. Currently, these medications are being studied and evaluated as treatment for COVID-19; however, their efficacy to either prevent or treat this infection are unknown. In overdose situations or when used inappropriately, these medications can lead to severe toxicity, including cardiac rhythm disturbances such as prolonged QT, severe hypokalemia, cardiovascular collapse, seizures, coma, and death. Inappropriate uses include taking commercially available non-pharmaceutical preparations, taking chloroquine phosphate or hydroxychloroquine sulfate without a prescription, and taking additional doses not recommended by a healthcare provider. Chloroquine phosphate has a narrow therapeutic index—it can be toxic at levels not much higher than those used for treatment—which raises the risk of inadvertent overdose.