– The nation’s shortage of execution drugs is becoming increasingly acute as more pharmacies conclude that supplying lethal chemicals is not worth the bad publicity and the legal and ethical risks.

The scarcity of drugs for lethal injections has forced states to scramble for substitutes. And experts say that whatever alternatives are found will almost certainly face costly court challenges made more complicated by laws that cloak the process in secrecy.

This week, the Tulsa, Okla.-based compounding pharmacy the Apothecary Shoppe agreed to stop selling pentobarbital to the Missouri Department of Corrections after the pharmacy was named in a lawsuit filed by death row inmate Michael Taylor asserting that the drug could cause “inhumane pain.”

Missouri previously paid $8,000 in cash for each dose of the drug. The settlement will probably mean changing execution procedures before Taylor is scheduled to die for raping and killing a 15-year-old girl in 1989. Gov. Jay Nixon said that Missouri is prepared to carry out the Feb. 26 execution but did not elaborate.

After Woodlands Compounding Pharmacy near Houston was revealed in October as the supplier for Texas, the pharmacy asked the state Department of Criminal Justice to return unused vials. The state refused to do so.

Texas has two executions scheduled for March and five others after the expiration date.

Texas Department of Criminal Justice spokesman Jason Clark the agency “continues to explore all options, including the continued use of pentobarbital or an alternate drug in the lethal injection process.”