A closer look at midazolam and pentobarbital, two drugs commonly used in US executions

States use a variety of drugs and drug combinations in lethal injections. Two of the most common are midazolam and pentobarbital.

Midazolam is a short-acting sedative used in a clinical setting to help patients feel sleepy and relaxed before surgery. It has come under scrutiny because it was part of drug combinations used in executions that went wrong in Ohio, Oklahoma and Arizona.

Once midazolam is administered, another drug or two other drugs are given to put the inmate to death.

Pentobarbital, a barbiturate that slows activity of the brain and nervous system, is often used by doctors to treat seizures and convulsions. In an execution, pentobarbital can be used in combination with other drugs or by itself. So far this year, 14 inmates have been executed by single-drug doses of pentobarbital — seven in Texas, six in Missouri and one in Georgia.