An antiviral drug that’s being tested in the United States has been found to be causing an unusual form of severe side effects in a group of patients, according to an investigation by Reuters Health.
The report on Monday showed that the drug was being tested by GlaxoSmithKline and Novartis.
Both drug companies declined to comment on the investigation, which was first reported by Reuters.
The FDA said it is taking the findings seriously and is reviewing the drug’s safety and efficacy.
One patient has experienced “severe fatigue, headaches, fatigue, abdominal pain, nausea and vomiting, nausea, diarrhea, weight loss and depression,” the FDA said.
“In another patient, it has caused a significant decrease in mental function, including paranoia, hallucinations, and delusions,” the agency said.
Novartic did not immediately respond to a request for comment on Monday.
The drug was developed in 2013 by drugmaker Novo Nordisk and Pfizer, which partnered on the drug.
It is designed to treat the common cold and is the most commonly prescribed antiviral medication in the U.S. for adults.
In its first clinical trial in late 2017, the drug showed a 95 percent success rate for people taking a 10-day course of the drug, according a Reuters analysis.
In 2018, the company raised the overall approval rate to 99 percent, but said the study was “not robust enough” to make any firm conclusions about the safety of the product.
The study also found that some of the patients who received the drug were taking the drug as a combination, or in two doses, which means that some patients might have been getting a different dose.
The company has also raised the approval rate for another antiviral treatment, dasatinib, to 100 percent from 65 percent.
Novo, Novartist, and Glaxos have been testing their own drugs for the past year and a half.
They said they’re working to find a way to reduce side effects and improve patient safety.
Reuters Health contributed to this report.