(Reuters) - A federal judge in Arkansas has blocked plans by the state to carry out a rapid series of executions, questioning the state's use of midazolam, one of the drugs it planned to use for lethal injection.
The case underscores a national issue for prisons: starting about six years ago, pharmaceutical makers have forbidden sales of their products to prison systems for use in lethal injections due to moral and ethical concerns.
Here is the state of play for the role of the drug industry in executions.
What drugs are used for lethal injections?
States have different protocols for lethal injections. Texas and four other states use only one drug for injections: pentobarbital, according to the Death Penalty Information Center. Arkansas planned to use three drugs: midazolam, vecuronium bromide and potassium chloride in its executions. The use of sodium thiopental for executions stalled after its U.S. maker restricted manufacturing in 2011 and the European Union banned its export for this purpose.
Which companies make these drugs and why?
While some of the drugs being used now for lethal injection have come to be known as execution drugs, they also have other uses. For example, Vecuronium bromide, which is made by Pfizer Inc, is used in general anesthesia. Last year, Pfizer imposed new controls to block the sale of its drugs for executions.
Fresenius Kabi USA, which is part of Germany's Fresenius, and West-Ward Pharmaceuticals Corp., a part of Jordan's Hikma Pharmaceuticals, also make drugs they said were to have been used in the Arkansas execution and filed a brief in that case saying they were not to be used.
Midazolam, widely used in three-drug execution cocktails, is a sedative and considered by the World Health Organization an essential medicine that nations should have on hand. Small batch drug makers called compounding pharmacies have stepped in to produce pentobarbital, which had been made by Denmark-based Lundbeck and U.S.-based Akorn Pharmaceuticals, after those companies restricted use of the drug in 2011 and the only U.S. maker of a similar drug, sodium thiopental, stopped producing it.
What are compounding pharmacies and why are they involved?
As drug companies - led on by large investors and advocates like London-based Reprieve - have clamped down, states have turned to pharmacies that make drugs. According to the Death Penalty Information Center, at least 10 states have used or planned to use these pharmacies - including South Dakota, Missouri, Texas, Georgia, Oklahoma and Virginia.
The U.S. Food & Drug Administration regulates drug manufacturers but not the thousands of compounders, which are overseen only by state pharmacy boards. The FDA has increased inspections after a deadly fungal meningitis outbreak several years ago brought the pharmacies to national attention. The light oversight has fed legal challenges that these drugs are untested and unsafe.
Which states are actively using lethal injection?
There have been six executions by injection in 2017 - four in Texas, one in Virginia and one in Missouri - and all used drugs made by compounders, according to the Death Penalty Information Center. In 2016, there were 20 executions: nine in Georgia, seven in Texas, two in Alabama, one in Florida, and one in Missouri.
Of the 31 states that have capital punishment, some have adopted laws that allow them to shield the identity of makers of their execution drugs, making it possible for them to obtain the drugs from compounders who fear retribution.
States have other methods for capital punishment. Oklahoma in November 2015 passed a low allowing the use of nitrogen gas while Utah allows for a firing squad, although it has not used that method since 2010.
(Reporting by Caroline Humer; Editing by Bill Trott)