A judge-alone trial will take place next year, the court heard.
A police summary of facts released to the ODT says the man involved in the April incident died of "acute shock" and a pre-existing medical condition.
The level of morphine and alcohol found in his blood were at a "therapeutic level".
The trio were drinking at a Dunedin house when the man allegedly asked the defendants to inject him with the prescription medication.
Potter's lawyer Anne Stevens said her client only mixed and administered the morphine sulphate after at least an hour's persistence on the part of the deceased.
He told police he wanted to give the man a "decent hit" and mixed two quantities of the medication in a shot glass.
In a second interview with officers he told them he had got the colours of the tablets mixed up and inadvertently administered more than he meant to.
The man fell asleep and the defendants went to bed in the early hours of the morning.
The female co-accused allegedly placed a pillow under the man's head and covered him with a blanket, convinced he was sleeping well.
But when they woke up at 7am, they found him unresponsive. He was pronounced dead 10 minutes later and police found a needle mark in his arm, the summary said.
Stevens said Potter had been prescribed morphine after a life as a truck driver left him with severe back problems.
