Critics are warning about the "very real risk of a botched execution" in what is to be the first US case of capital punishment using fentanyl.
A USA judge has effectively put the execution of a two-time killer on hold after a pharmaceutical company objected to the use of one of its drugs to put someone to death.
Pfizer protested previous year, but Nevada refused the pharmaceutical company's demand to return the diazepam and fentanyl it manufactured. But Dozier has waved appeals and said he wants to die so the combination of medicines to be used to kill him has not been examined in court.
The department of corrections will not comment on the case.
Dunham, the Death Penalty Information Center official, said that if cisatracurium is used in the the Nevada execution, it would be the first time that a state publicly acknowledged using it to execute an inmate.
This is the second lawsuit of its kind in the USA from a pharmaceutical company, according to the Death Penalty Information Center, which tracks data about the death penalty and has criticized the way capital punishment is administered in America.
New Jersey-based Alvogen had urged the judge to block the use of its sedative midazolam, saying the state illegally secured the product through "subterfuge" and intended it for unapproved purposes.
"Alvogen has undertaken controls to avoid diversion of this product for use in execution protocols", the company states on its website concerning midazolam.
Foa said that states are usually obliged by the appeals process to subject the planned method of execution to legal scrutiny, particularly when a new drug protocol is being used.
The state intends to use a synthetic opioid - involved in more than 20,000 overdose deaths in 2016 alone - to kill Scott Dozier, a double murderer, after finding it hard to obtain other drugs for Nevada's first execution in 12 years because of opposition from pharmaceutical manufacturers.
The lawsuit said that to perpetuate the deception, the authorities had the midazolam shipped to the department of correction's central pharmacy rather than to the prison where the execution is to take place.
A lawsuit filed by the pharmaceutical company Alvogen, however, put Dozier's execution by lethal injection on hold.
Fentanyl, which has been blamed for deadly overdoses across the country, has not been used before in an execution.
Midazolam was substituted in May for expired prison stocks of diazepam, a similar sedative commonly known as Valium.
Jordan T. Smith, an assistant Nevada solicitor general, countered at Wednesday's hearing that Nevada didn't put up a "smokescreen" or do anything wrong in getting the drugs.
"I've been very clear about my desire to be executed ... even if suffering is inevitable", he said in a handwritten note to a judge who postponed his execution in November over concerns the untried drug regimen could leave him suffocating, conscious and unable to move.
"Life in prison isn't a life", the Army veteran and methamphetamine user and dealer told the Las Vegas Review-Journal recently. Fentanyl is used to slow the heart rate, sedate and continue to suppress breathing, and finally Cisatracurium to paralyze the inmate before death.
In court hearings and letters, he said there is a limit to how much artwork and exercise a person can do in prison.
In 2005, Dozier was sentenced to 22 years in prison for shooting 26-year-old Jasen Greene, whose body was found in 2002 in a shallow grave outside Phoenix.
Scott Dozier was sentenced to die for the 2002 robbing, killing and dismembering of a 22 year old man in a Las Vegas motel.
One of the letters was sent to Nevada's Ely state prison where executions are carried out, addressed to the warden, Timothy Filson.
Mr Miller had come to Nevada to buy ingredients to make meth. The victim's torso was found in a suitcase dumped in a trash bin in Las Vegas, according to the Nevada Department of Corrections.
Although Dozier dropped attempts to save his own life, he allowed federal public defenders to challenge the execution protocol.
Midazolam has been used with inconsistent results in states including Alabama, Arkansas, Arizona, Florida and Ohio.
They argued that the untried three-drug combination would be less humane than putting down a pet.