Nevada thus became the fifth state to stop a scheduled execution since Sept. 25, when the United States Supreme Court agreed to hear a similar appeal by two men on Kentucky’s death row.

Lawyers for the Kentucky men argued that the first drug administered, sodium thiopental, sometimes failed to render an inmate fully unconscious, allowing him to experience pain. Meanwhile, the second drug, pancuronium bromide, paralyzes him and leaves him without the ability to move or call for help as the third drug, potassium chloride, stops the heart, an often painful process. That combination, opponents say, violates the Eighth Amendment prohibiting cruel and unusual punishment.

Unlike in the Kentucky case, though, the Nevada inmate, William Castillo, 34, did not wish to postpone his execution and instructed his court-appointed lawyer not to appeal. But the American Civil Liberties Union of Nevada was granted legal standing to oppose Mr. Castillo’s execution on behalf of a Spanish-language newspaper in the Reno area, Ahora, which contends that masking the suffering of a dying inmate violates the news media’s right to observe the impact of the punishment.

"From our point of view, this is an issue of broader First Amendment principle," said Lee Rowland, the A.C.L.U. lawyer who argued the case. “This is not simply a matter of one person’s request to die. It’s about the broader power of the state. No one, not Mr. Castillo or you or I, has the right to petition the government to be tortured.”

Of the 38 states with the death penalty, all but one use lethal injection. Nebraska uses the electric chair. Since the United States Supreme Court agreed to hear the Kentucky case, the top courts in Arizona, Arkansas, Delaware and Texas ruled that all lethal injection executions must wait until the Supreme Court’s ruling.

In Nevada, lawyers are expected to argue for the stay to be extended until the ruling by the United States Supreme Court.

The director of the Nevada Department of Corrections, Howard Skolnik, said Mr. Castillo was disappointed by the delay. Mr. Castillo was condemned for the 1995 slaying of a retired Las Vegas teacher, Isabelle Berndt, 86.