A young toddler tragically died in his rural NSW home over 19 years ago after being given antidepressants by his mother's partner, a jury has heard.
Jordan Thompson was found unresponsive and rushed to Singleton hospital in the NSW Hunter region on March 19, 2005.
He was under the care of Cecil Patrick Kennedy at a nearby unit after his mother Bernice Swales popped out to the shops.
Kennedy has since been charged with manslaughter over Jordan's death and is facing two-month long trial in Sydney's Downing Centre District Court.
On Tuesday, crown prosecutor Kate Nightingale said the toddler appeared healthy when he was collected by his father three days before the tragedy.
The morning before he passed away, Jordan was fussy and crying when Kennedy took him into his bedroom, the jury heard.
After that, the 21-month-old was seen dozy and unsteady on his feet.
He threw up the pancakes and chocolate milk he had for breakfast and had to be bathed before Ms Swales put him to bed and headed to the shops.
When she returned, she thought she heard Kennedy shouting for help, entering the unit to find her son naked and unresponsive on a bed with her partner attempting CPR, Ms Nightingale said.
Jordan was whisked to hospital where he was seen to be flaccid and pale with no signs of life.
He was pronounced dead just before 7pm.
Ms Nightingale said analysis of Jordan's blood, urine, stomach and liver found traces of the antidepressant amitriptyline, which is sold under the brand name Endep.
Kennedy was the only person close to the child who had been prescribed that drug, with police finding an Endep box with two full blister packs in his cupboard during a search of his premises, she said.
The now 52-year-old had changed his story about what happened to Jordan, initially telling Ms Swales that her child had either fallen into or out of the bathtub, the jury heard.
He later told police he had left the toddler unattended in the bathtub for about 40 seconds before returning to find him face-down in the water, Ms Nightingale said.
Ms Swales and hospital staff noted that Jordan's body and hair were dry, and police officers did not find water on the tiles or carpet in the home, the jury heard.
After police informed him that antidepressants had been found in Jordan's system, Kennedy and his mother allegedly went over to his apartment to try and remove the medication.
They also allegedly discussed lying to police in phone calls recorded by officers investigating the case.
He has always denied drugging the child.
Ms Nightingale said the jury would have to consider whether Jordan died of amitriptyline toxicity or was substantially impaired by the drug leading to him drowning in the bathtub.
Kennedy's barrister Linda McSpedden said there was a third option - namely that the toddler simply died as a result of drowning.
Experts who will give evidence in the trial disagreed on the cause of death, meaning that the Crown could not prove its allegations beyond reasonable doubt, she said.
She acknowledged that the case was a horrible tragedy, but urged jurors to put their emotions aside and look at the evidence objectively.
The trial before Judge Craig Smith continues on Wednesday.
