BRASILIA, Brazil (AP) — Irene Castilho, 71, didn’t even have a day to grieve after her husband died of COVID-19. She was sick, too, coughing and struggling to breathe; he was barely gone when she started using his oxygen mask. The same day, on March 22, she was admitted to a hospital in Sao Paulo.

Luiz Cezar Pereira speaks next to his father Pedro Pereira Filho during an interview at their home in Guarulhos, Brazil, Friday, Oct. 1, 2021. Luiz's mother, Pedro's wife, died of COVID-19 and was treated by health care company Prevent Senior, which is under investigation for allegedly forcing doctors to test unproven drugs on coronavirus patients. She was treated with flutamide, a drug typically used for prostate cancer, for which Luiz eventually consented after resisting when his online research found it wasn’t scientifically proven. (AP Photo/Marcelo Chello)

Luiz Cezar Pereira speaks next to his father Pedro Pereira Filho during an interview at their home in Guarulhos, Brazil, Friday, Oct. 1, 2021. Luiz's mother, Pedro's wife, died of COVID-19 and was treated by health care company Prevent Senior, which is under investigation for allegedly forcing doctors to test unproven drugs on coronavirus patients. She was treated with flutamide, a drug typically used for prostate cancer, for which Luiz eventually consented after resisting when his online research found it wasn’t scientifically proven. (AP Photo/Marcelo Chello)

BRASILIA, Brazil (AP) — Irene Castilho, 71, didn’t even have a day to grieve after her husband died of COVID-19. She was sick, too, coughing and struggling to breathe; he was barely gone when she started using his oxygen mask. The same day, on March 22, she was admitted to a hospital in Sao Paulo.

She had followed doctors’ instructions to the letter – dutifully taking her doses of hydroxychloroquine. She also took ivermectin and a battery of anti-inflammatories and vitamins in the so-called “COVID kit” that her health care company, Prevent Senior, mailed to her home.

Still, her condition had deteriorated.

At the hospital, physicians consulted Castilho’s daughters about giving her flutamide — a drug typically used for prostate cancer – but they declined, worried about possible side effects for their mother, who recently had liver cancer.

They later saw a nurse administering flutamide; she told them it had been prescribed despite their objection.

Castilho died in late April, 33 days after her husband.

Castilho’s case is one of a series of examples that have led to explosive accusations against Prevent Senior, which operates 10 hospitals in Sao Paulo, that have scandalized Brazil.

Whistleblowing doctors, through their lawyer, testified at the Senate last week that Prevent Senior tested drugs without proper consent and forced doctors to prescribe unproven drugs touted by President Jair Bolsonaro.

Some senators have said it appears Prevent Senior falsified death certificates to omit COVID-19 as cause of death. Authorities are also investigating complaints the company conducted research without proper authorization.

Two weeks ago, Pedro Batista Júnior, Prevent Senior’s executive director, testified to senators that doctors were free to make their own prescriptions for treatment of COVID-19 and said patients had freely agreed to take their COVID kits.

Luiz Cezar Pereira shows his late mother's sewing machine at his family's home in Guarulhos, Brazil, Friday, Oct. 1, 2021. Pereira's mother died of COVID-19 and was treated by health care company Prevent Senior, which is under investigation for allegedly forcing doctors to test unproven drugs on coronavirus patients. Pereira's mother was treated with flutamide, a drug typically used for prostate cancer, for which he eventually consented after resisting when his online research found it wasn’t scientifically proven. (AP Photo/Marcelo Chello)

Luiz Cezar Pereira shows his late mother's sewing machine at his family's home in Guarulhos, Brazil, Friday, Oct. 1, 2021. Pereira's mother died of COVID-19 and was treated by health care company Prevent Senior, which is under investigation for allegedly forcing doctors to test unproven drugs on coronavirus patients. Pereira's mother was treated with flutamide, a drug typically used for prostate cancer, for which he eventually consented after resisting when his online research found it wasn’t scientifically proven. (AP Photo/Marcelo Chello)

In response to questions from the AP, Prevent Senior denied all wrongdoing, irregularities at its facilities or having conducted unapproved trials. It said all patients or family members consented before receiving treatment.

Care at Brazil's public health care system is often subpar. Many middle-class Brazilians have private plans, but costs for the elderly are high.

Prevent Senior seemed to help fill that gap. It was founded in 1997 and grew among those who couldn’t afford premium care; its monthly cost is about $300, half that of some competitors. The company has more than 500,000 clients, with an average age of 68.

Hydroxychloroquine has been promoted by Bolsonaro and his allies. While a few studies at the pandemic’s onset suggested it might be promising, they were largely conducted in lab dishes. Extensive worldwide research has long since found it to be ineffective for COVID-19 and potentially dangerous.

Doctors also said they were told to prescribe ivermectin, an anti-parasite drug whose effectiveness for COVID-19 remains unproven. The American Medical Association recommends against prescribing it outside of formal trials.

Pressure to prescribe hydroxychloroquine and ivermectin is corroborated by internal Prevent Senior chat groups on WhatsApp obtained by The Associated Press, and which were previously shared with the Senate committee investigating the nation’s COVID-19 response.

They include messages sent by Benedito Júnior and another executive, two current clinic directors, one former clinic director, and an unnamed physician.

Lawyer Bruna Morato, who represents 12 doctors currently or previously employed by Prevent Senior, told senators on Sept. 28 that her clients were repeatedly told to choose between prescribing dubious drugs or losing their jobs.

Prevent Senior insisted that doctors had been free to prescribe the COVID kit or not.

Prevent Senior told the AP that it wasn’t formally testing flutamide, but said doctors were allowed to administer it. The company maintained that the drug can be helpful in treating COVID-19.

Jorge Venâncio, commissioner of Brazil’s National Research Ethics Commission, told the AP that the only application Prevent Senior filed for COVID-19 research was related to hydroxychloroquine and azithromycin, an anti-inflammatory that also hasn’t proven helpful.

He said the council approved that request to start trials in April 2020 and the hospital published its results just three days later, indicating the study had already been done.

Prevent Senior told the AP it was not a scientific study, but rather an “observational report” comparing patients who received hydroxychloroquine and azithromycin with others who didn’t take them, and so wouldn’t need registration.

“Even if it were observational research, as they’re saying now, it would have to be registered,” Venâncio said.

Prosecutors in Sao Paulo who are investigating the healthcare provider received that information from the research council, as well as complaints from doctors and patients.

Lawmakers are also investigating possible fraud in death certificates. In May 2020, the Health Ministry issued guidelines stating that a death stemming from COVID-19 should be classified as such on a death certificate, even if the patient had stopped testing positive for the virus.

But that didn’t always happen. Luciano Hang, a department store magnate who is a fervent Bolsonaro supporter, told senators his mother was admitted to a Prevent Senior facility in Sao Paulo with COVID-19. Yet the disease doesn’t appear on her death certificate, a copy of which the AP reviewed.

It remains unclear whether that means patients’ deaths were omitted from state and national tallies of COVID-19 deaths. Prevent Senior told the AP that this didn’t interfere with compulsory notification to authorities.

Neither Sao Paulo nor federal health officials said whether patients who died of COVID-19 at Prevent Senior facilities factored into the nation’s death toll, which is the world’s second highest at more than 600,000.

Many say the revelations from Prevent Senior reflect what is going on elsewhere. The government regulator of private health care plans said in a statement to the AP it is investigating Hapvida, Prevent Senior and another provider, Unimed Fortaleza. Sao Paulo’s medical council also is investigating Prevent Senior.

The Senate committee aims to release its final report within two weeks and some lawmakers have already signaled they want to make an example of Prevent Senior.

Sen. Renan Calheiros, who is assigned to write the report, told the AP: “Prevent Senior is the most shocking case investigated by this committee from a humanitarian and civilizational perspective.” ___

AP journalists Tatiana Pollastri and Mauricio Savarese contributed from Sao Paulo