July 6 (UPI) -- Prescriptions for chloroquine rose 159 percent across the United States in February and March, the early days on the COVID-19 outbreak, according to an analysis published Monday by JAMA Internal Medicine.
Prescriptions for the companion drug hydroxycholoroquine increased by 86 percent over the same period, the researchers from the Centers for Disease Control and Prevention said.
To date, little scientific evidence exists to support hydroxychloroquine's use to treat COVID-19, the disease caused by the new coronavirus, SARS-CoV-2.
"In one month, approximately 300,000 additional patients received hydroxychloroquine from retail pharmacies," the study's authors wrote.
The World Health Organization and the U.S. National Institutes of Health have discontinued studies of the drug in COVID-19 patients over concerns regarding serious, life-threatening side effects.
The estimated number of Americans who received prescriptions for both hydroxychloroquine and azithromycin -- the antiviral that has been paired with the malaria drug in COVID-19 studies -- increased 1,044 percent in February and March, the researchers said.
Overall, the estimated number of patients who received dispensed hydroxychloroquine or chloroquine increased for all 50 states and Washington, D.C., with the highest percentage increases in New Jersey at more than 190 percent; Florida, at 157 percent; Hawaii, at 130 percent; and New York, at 123 percent, they said.
The smallest percentage increases were reported in South Dakota, at 37 percent, and Iowa, at 44, they said.
"Evidence of efficacy in preventing or treating COVID-19 is limited," the CDC authors wrote. "Treatment guidelines found insufficient clinical data to recommend for or against hydroxychloroquine or chloroquine use and recommend against combining either with azithromycin, except in clinical trials."