TALLAHASSEE (CBSMiami/AP) — Death row inmates trying to stop the use of a new drug mix used in lethal injections, asked  federal courts Tuesday to declare it unconstitutional.

The claims say the  use of the sedative midazolam hydrochloride won’t prevent excruciating pain and suffering when the next two drugs are administered. Use of the mix would be a form of cruel and unusual punishment, thus violating the condemned prisoner’s right, according to the complaints.

Florida used the new mix during the execution of William Happ on Oct. 15. It was the first time it was used in an execution and Happ didn’t file any appeals challenging its use. It appeared to an Associated Press reporter that it took longer for Happ to lose consciousness than others who have been executed under the previous drug mix, which used pentobarbital to render prisoners unconscious before drugs that induce paralysis and cardiac arrest are administered.

Seven death row inmates are challenging the new procedure in U.S. District Courts in Jacksonville, Ocala, Tampa and Orlando. The inmates had previously sued to stop the previous lethal injection drug mix and filed amended complaints to reflect the new procedures.

“Midazolam is not intended for use as an anesthetic,” the suit said, adding that it is typically used to sedate patients before anesthesia is administered. “Its use in this context is wholly untested.”

It claims that because the second drug used in the mix causes paralysis, the condemned would not be able to express the severe pain he or she is going through. About seven minutes after Happ’s execution began, he moved his head around and appeared to swallow.

The Florida State Prison warden and Department of Corrections Secretary Michael Crews are named as defendants in the suit. A federal judge in Jacksonville will hold a hearing on the complaints Nov. 6. The Department of Corrections didn’t immediately respond to emails and a phone message seeking comment on the complaints.

Florida is scheduled to execute Darius Kimbrough on Nov. 12. He isn’t one of the plaintiffs in the lawsuits challenging the lethal injection procedures.

Ohio plans to use a combination of midazolam and hydromorphone, a painkiller, in a Nov. 14 execution. It will be the state’s first time using that mix. Kentucky has procedures to use the two-drug combination as a backup, but hasn’t used it during an execution.

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