Gov. Jay Nixon halted Allen Nicklasson’s Oct. 23 execution following doctor protests along with threats from the anti-death penalty European Union to limit the drug’s export. Nixon ordered the state corrections department to come up with a different lethal injection protocol and instructed Attorney General Chris Koster to ask the state Supreme Court to set a new execution date for Nicklasson.

Other states, including Ohio and Texas, have turned to private compounding pharmacies to prepare new batches of the sedative pentobarbital after large drug manufacturers balked, a move Missouri could follow. It could also seek to administer a different FDA-approved sedative such as midazolam, also an untested execution drug which the state of Florida plans to provide Tuesday night as part of a three-drug mix for William Happ, a house painter convicted in a Fort Lauderdale rape and strangulation.

Another possible scenario for Missouri: months if not years of continued legal challenges. Nicklasson’s lawyer has asked the state Supreme Court to not rule on the request for a date until officials select a new death penalty drug.

“You can’t set an execution date now,” said attorney Jennifer Herndon. “There’s not even a protocol …The state’s request for a new execution date is premature.”

Nicklasson was convicted of the 1994 killing of Excelsior Springs businessman Richard Drummond. A car carrying Nicklasson and two others broke down on Interstate 70 in central Missouri. Drummond, a Vietnam War veteran, stopped to help and was then kidnapped, robbed and shot in the woods off the interstate. Another man in the car, Dennis Skillicorn, was executed in 2009.

Another execution is scheduled — for now — on Nov. 20. Joseph Franklin was convicted in the 1977 sniper shooting of Gerald Gordon as a crowd dispersed from a bar mitzvah in suburban St. Louis. Two others were wounded. When he confessed 17 years later, Franklin was serving several life sentences in a federal prison for killing two black joggers in Salt Lake City and an interracial couple in Madison, Wis., and bombing a synagogue in Chattanooga, Tenn.

Koster’s written request to the Missouri Supreme Court asks Nicklasson be executed “soon after” Franklin. A Koster spokeswoman said there were no new developments Tuesday, as did a Department of Corrections official.

Unlike propofol and other more widely available drugs previously used in executions, drugs manufactured by compounding pharmacies aren’t regulated by the federal Food and Drug Administration, raising questions among death penalty opponents and public health watchdogs alike. A deadly nationwide meningitis outbreak last year in which 64 people died and 750 others sickened was traced to a tainted steroid custom-made by a Massachusetts compounding pharmacy.

Such businesses also risk public backlash once their identities are revealed. A suburban Houston compounding pharmacy that supplied a special batch of pentobarbital to the Texas prison where an inmate was executed last week asked to have the drug returned after complaining about “a firestorm” of public attention, including hate mail.

“There’s going to be pressure,” said attorney Richard Deiter, executive director of the Washington-based Death Penalty Information Center. “Everybody in the medical business has their ethical codes — and the death penalty usually isn’t a part of it.”

In Arkansas, Attorney General Dustin McDaniel recently told a statewide group of local sheriffs that the state’s death penalty system is “completely broken” and called lethal injection a “legal fallacy” given the drug shortage. He suggested the state either overhaul its death penalty laws or abolish it completely.

Missouri altered its execution protocol in April 2012 to include propofol only after it could no longer obtain the other lethal injection drugs it had previously used for a three-drug mix.

The decision to use propofol, the drug best known for contributing to pop star Michael Jackson’s 2009 overdose, quickly prompted a lawsuit filed on behalf of nearly two dozen death row inmates who claimed that using the unproven execution drug could result in pain and suffering for the condemned.