Image copyright AP Image caption Dennis McGuire was sentenced to death for the 1989 murder of a young woman (file photo)

A man convicted of murder in the US state of Ohio has been executed using a new, never-before-tried lethal injection combination.

Dennis McGuire, 53, was killed on Thursday with a two-drug cocktail, after the maker of the previous execution drug refused to allow its use in capital punishment.

McGuire appeared to gasp and snort over the 15 minutes it took him to die.

He was sentenced to death for the 1989 rape and murder of Joy Stewart.

Stewart was pregnant.

In recent years, US states have had increasing difficulty obtaining drugs for use in lethal injections, as their manufacturers have grown unwilling to provide them for that use.

Ohio officials elected to use intravenous doses of the sedative midazolam and painkiller hydromorphone for McGuire's execution.

Lawyers for McGuire had said the drugs placed him at risk of air hunger, a phenomenon which causes terror as the patient struggles to catch his breath.

During the procedure, McGuire gasped several times and his mouth repeatedly opened and closed, according to an Associated Press news agency reporter who witnessed the execution.

An Ohio federal judge had rejected a last-minute appeal to delay the execution after McGuire's legal team argued a jury never heard details of his reportedly troubled childhood.

McGuire's lawyers alleged he was abused, leading to impaired brain function that made him prone to impulsive actions.

Ohio Governor John Kasich also rejected McGuire's efforts to become an organ donor, a legal manoeuvre that previously allowed another death row inmate an eight-month reprieve.