The White House said such a drug would be used as a prophylactic to defend nurses, doctors, and other health care professionals against the virus.
The U.S. donation, however, arrived in a country already overflowing with the drug given that local authorities keep an annual stock of it to fight malaria.
The Bolsonaro administration even increased the production of that substance under the assumption that hydroxychloroquine would help defeat the coronavirus, which is something that scientific studies do not support.
Despite the government's enthusiasm for this alleged solution, many doctors have stopped prescribing hydroxychloroquine in this South American country.
Nevertheless, a recent survey shows that half of the doctors interviewed felt being pressured by their patients to prescribe that ineffective drug.
Former Health Minister Luiz Mandetta described the public demand for hydroxychloroquine as false hope. He said that, from the very beginning of the pandemic, Bolsonaro knew science didn't back his choice for that drug.
The country's surplus of hydroxychloroquine comes amid an urgent need for other drugs to help COVID-19 patients.
Intensive Care Unit (ICU) doctor Pedro Archer mentioned that he fears the focus on hydroxychloroquine has diverted the government's attention away from obtaining medications that coronavirus patients need.
"Midazolam, Fentanyl, Noradrenaline. The public health system is always running out of these," he said, referring to vital drugs used to keep patients alive and comfortable in an ICU.
"If the U.S. wants to help Brazil, it should send these drugs, not hydroxychloroquine," he added.