Three-drug lethal injection (midazolam)

This article explains how the method works at the level reported in court records and the news. It does not include doses or technical instructions.

Overview

This three-drug method begins with the sedative midazolam. It is used by Oklahoma and Alabama. States adopted midazolam in the 2010s after the drugs previously used to make prisoners unconscious became unavailable. It has been one of the most legally contested execution drugs in the United States.

How it works

1. Midazolam, a sedative of the benzodiazepine family, is intended to make the prisoner unconscious.
2. A paralytic stops muscle movement, including breathing. Oklahoma uses vecuronium bromide; Alabama uses rocuronium bromide.
3. Potassium chloride stops the heart.

How it is administered

The three drugs are given intravenously, one after another, through lines placed in the prisoner's veins. As with other three-drug methods, the protocol relies on the prisoner being unconscious before the second and third drugs are given.

What the prisoner may experience

This is the central dispute about midazolam. Critics, including anaesthesiologists who have testified for prisoners, say midazolam is a sedative rather than a true anaesthetic and cannot reliably keep a person unconscious through the paralytic and potassium chloride, which they say would cause severe pain and a sensation of suffocation in someone not fully unconscious. A federal judge in Ohio once compared such a protocol to waterboarding, suffocation and chemical fire.

States and their experts disagree. In 2022, after a week-long trial, a federal judge in Oklahoma ruled that although midazolam "is not the drug of choice for maintaining prolonged deep anesthesia, it can be relied upon" to keep a prisoner insensate to pain for the few minutes the execution takes. The US Supreme Court also upheld a midazolam protocol in 2015.

How long it takes

Most executions with this method are completed within minutes, but it has been involved in some of the longest and most troubled executions of the past decade, including in Oklahoma, Arizona, Ohio and Alabama, which critics say shows its unreliability.

Cost

Oklahoma and Alabama do not publish what they pay for these drugs, and supplier details are kept confidential. All three drugs have common hospital uses.

Availability

Midazolam is widely used in medicine, but many manufacturers forbid its sale for executions, so states rely on undisclosed sources. Oklahoma has previously made errors with its drug supply: in 2015 it used the wrong heart-stopping drug in one execution and called off another after receiving the wrong drug.

Where it is used

Oklahoma (midazolam, vecuronium bromide, potassium chloride) and Alabama (midazolam, rocuronium bromide, potassium chloride). Other states have authorised it in the past or as an alternative.

Sources

1. Death Penalty Information Center: federal judge upholds Oklahoma protocol (2022)
2. Newsweek: Oklahoma protocol upheld
3. American Bar Association: Oklahoma ruling and background
4. Death Penalty Information Center: Oklahoma returns to midazolam (2020)
5. Lethal Injection Information Center: protocols state by state
6. medRxiv: autopsy findings after lethal injection