(Bloomberg) --

Drugs for malaria and certain autoimmune diseases that President Donald Trump touted as Covid-19 treatments have been added to the Food and Drug Administration’s shortage website.

Some patients who took the medications for rheumatoid arthritis, lupus and other disorders before the coronavirus pandemic are now unable to fill prescriptions. Demand surged after doctors overseas said they had seen some signs that the drugs could be used to treat Covid-19, the respiratory illness caused by the new coronavirus.

There have been no definitive studies showing that hydroxychloroquine and the drug it is derived from, the more toxic chloroquine, are effective treatments for Covid-19.

Some of the nine companies on the FDA’s list that make hydroxychloroquine, including generic-drug giant Teva Pharmaceutical Industries Ltd., said there is a limited supply that is subject to allocation. Others said the drug is available, particularly for existing customers. Increasingly larger shipments of chloroquine are scheduled over the next eight months, according to Natco Pharma Ltd., whose chloroquine is distributed by Rising Pharmaceuticals Inc.

“The agency is working with manufacturers to assess their supplies and is actively evaluating market demand for patients dependent on hydroxychloroquine and chloroquine for treatment of malaria, lupus and rheumatoid arthritis,” the FDA said in a statement Tuesday evening. All manufacturers are ramping up production.”

Novartis AG’s Sandoz has donated 30 million doses of hydroxychloroquine and Bayer AG donated 1 million doses of chloroquine to the national stockpile that can be used for Covid-19 patients in an effort to help ease supply concerns.

©2020 Bloomberg L.P.