A German study made on patients who had strokes showed that many of them had been treated with an anemia drug released by Johnson & Johnson, as federal health official reported on Friday. The FDA now seeks answers for the higher death rates among those patients.

The Food and Drug Administration said that 16% of the patients who were given Eprex, the drug from Johnson & Johnson, died three months after they were given the pill. Still, only 9% of the patients who were given a placebo faced death in the months after the treatment.

Eprex, an unapproved use of drug, was tested to see if it can improve the brain function in stroke patients. But the FDA said that 522 patients who took high doses of Eprex for three days were mostly anemic than to have had an improved brain function.

Johnson & Johnson produced Eprex, which is also known as epoetin alfa, and Procrit, a name which hides the epoetin alfa in it. Epoetin alfa is also produced by Amgen, which sells it as Epogen. These drugs are part of a class named erythropoiesis-stimulating agents, which are usually released to treat kidney disease and cancer.

But as recent studies have shown, many of the patients who took a high dosage of these drugs were found to have tumor growth or have died shortly after they had taken the drug. Regarding this, the FDA released warning on the medicines since July.