Taking multiple drugs at the same time could affect their effectiveness and increase the risk of harmful drug interactions, said Dr. McGinn.
"You give remdesivir, you give dexamethasone and you give monoclonal antibodies," he said, referring to the experimental treatment by Regeneron. "Nobody has ever done that, let alone famotidine and some zinc and a mix of cocktails or whatever else they make."
The uncertainty about the state of the President was at least in part due to mixed signals from the President's doctors. On Sunday, the team admitted they made an overly positive description of the president's illness on Saturday.
"I didn't want to give any information that might steer the course of the disease in any other direction, and it turned out that we were trying to hide something that wasn't necessarily true," said Dr. Sean P. Conley, the White House doctor, told reporters on Sunday.
Dr. Rajesh Gandhi, an infectious disease doctor at Massachusetts General Hospital and a member of the panel that developed Covid-19 treatment guidelines for the NIH, said, "It would be very helpful to know how much oxygen the president needs and what for and for how long."
The president's doctors have also not detailed the results of imaging scans of Mr Trump's lungs or blood tests that show he is at risk for blood clots, a common complication of Covid-19 disease.
Mr Trump is moderately obese, a condition that is usually accompanied by at least mild or moderate high blood pressure and mild to moderate diabetes, noted Dr. McGinn. The president's high blood pressure is said to be under control and he is not known to have type 2 diabetes. Still, studies have identified the conditions as critical predictors of severe Covid-19 disease.