Timeline: A History of Lethal Drug Use in Texas

For nearly 30 years, Texas used the same three-drug lethal injection cocktail to execute death row inmates: sodium thiopental, an anesthetic, followed by pancuronium bromide, a muscle relaxant, and then potassium chloride, which brings about cardiac arrest. 

Drug manufacturers in the U.S. and abroad began cutting off supplies in 2011, refusing to allow their use in executions. The dwindling supply set in motion a national scramble among death penalty states, including Texas, to find drugs that could be used to administer the ultimate punishment. 

Relying on news stories and TDCJ documents provided to death row inmates' attorneys, The Texas Tribune compiled a timeline of TDCJ’s drug purchases and its use of execution drugs since 2011.

Among the most controversial developments in Texas and other states has been the use of a new type of vendor: compounding pharmacies. The state-regulated entities can mix, or "compound," the drugs needed for lethal injections. But the pharmacies aren't subject to federal drug regulations. 

When the names of some compounding pharmacies surfaced publicly for the first time last year, they quit providing the drugs and even asked TDCJ to return them, citing harassment they suffered.

Both the concern over dwindling supply and the security concerns of drug suppliers have prompted TDCJ and other state prison systems to seek to severely limit the release of information about the sources of execution drugs. 

After years of telling TDCJ to release information about the death penalty process to the public, Texas Attorney General and gubernatorial candidate Greg Abbott in May ruled that the prison system had proved a threat existed to compounding pharmacies if the companies' identities were revealed. In a reversal of his previous decisions, Abbott ruled that information about the source of execution drugs can remain secret.