Joshua Gafney death: Nurse Amanda Young on trial
A nurse killed a patient with a "massive overdose" of an anti-psychotic drug, a court has heard.
Amanda Young is accused of administering a lethal dose of the drug to Joshua Gafney, 22, at his home in February 2012.
Bristol Crown Court was told Mr Gafney had been given 14 times the amount of clozapine needed to treat him.
Ms Young, 40, from Yeovil, denies manslaughter by gross negligence. Her trial is expected to last three weeks.
Mr Gafney had serious mental health issues and was suffering from paranoid schizophrenia, the court heard.
Prosecuting, John Price QC told the jury Mr Gafney had been given a "massive overdose" of a drug he had been prescribed to treat a serious condition he had.
Ms Young was instructed to administer 6ml - a little more than a teaspoon - of clozapine to Mr Gafney but the court heard she "hadn't seen" the dosage written on the medication.
Instead she poured six bottles into a glass for him.
She mistakenly believed each 14ml bottle contained 50mg of clozapine when in fact this figure was per millilitre - meaning a single container actually had 700mg inside, the court heard.
His mother, Tina Marren, immediately raised concerns at the half-full glass but Ms Young allegedly replied: "I know, we will put a bit of water with it".
Mr Gafney drank the glass, containing 84ml, and was pronounced dead two hours later.
Mr Price said there was "no doubt" Ms Young gave the "fatal dose" and that "she was at fault for his death," he said.
The trial continues.