Here’s a WaPost article about the fights between FDA, Department of Justice and Texas, on the issue of using and obtaining drugs for execution. I’m afraid it’s pay-walled.
Short version is that there is a 2012 injunction which bars the FDA from allowing the import of sodium thiopental, so they wouldn’t allow Texas to import the drug. However, AG Sessions argued that drugs for death penalty purposes are not within the FDA’s mandate, which a DOJ opinion in 2019 confirmed. The article (from 2019) says that litigation was likely over that opinion.
The US manufacturer of sodium thiopental, Hospira, stopped making it, because it was used for the death penalty, according to the article.