Florida's executed its first death row inmate in more than 18 months - using a drug that's never been used in a lethal injection before in the US.

The lethal cocktail included the anaesthetic etomidate, which replaces the controversial midazolam.

The Florida Department of Corrections confirmed that inmate Mark James Asay (53) was put to death at 6.22pm local time yesterday evening.

A spokesperson said there was no complication during the controversial procedure.

Asay had been on death row since 1988, after being convicted of killing two men.

He has become the first white inmate to be executed in Florida for killing a black man since the 1970s.

The state reintroduced the death penalty in the late 1970s, after it had been effectively outlawed for 15 years.