Expert says no evidence drugs played role in admission of Ashling Murphy killing

There was no evidence to suggest that an admission from the man accused of killing Ashling Murphy was related to any drug, a court has been told by a pharmacology expert.

Ms Murphy, 23, was killed while exercising on a canal path in Tullamore, Co Offaly, at about 3.30pm on January 12 last year.

Jozef Puska, 33, of Lynally Grove in Mucklagh, Tullamore, has pleaded not guilty to the schoolteacher’s murder.

The court had been told last week that Puska admitted killing her while speaking to gardai in hospital.

Detective Garda Brian Jennings told the court he had questioned Puska at St James’s Hospital in Dublin with the assistance of an interpreter on January 14.

Mr Jennings said Puska made the admission after he had been informed he was a “person of interest” in the murder of Ms Murphy.

Relaying the translation of the interpreter, the garda said: “He paused and said he is making an official statement that he is admitting that he committed the murder: ‘I did it. I murdered. I am the murderer’.”

Appearing before the Central Criminal Court on Tuesday, Professor Michael Ryan said the level of drugs in Puska’s system at the time would not have had an effect on his mood or behaviour.

The defendant had been taken to hospital by ambulance on January 13.

He told the jury he had examined the medical records of drugs administered to Puska prior to the alleged admission.

Prof Ryan, who was described as an internationally renowned expert in toxicology and pharmacology, said he went through extensive medical records “very carefully”.

He told the court he had all the necessary information and had started with Puska’s ambulance journey.

Prof Ryan explained that he looked at what drugs were administered, what possible effects they could produce, how much was administered and what was the “half life” of the drugs.

He said the half life was a measure of how long the drug stays in the body and that 50% of the substance would be gone after one half life.

Prof Ryan said Puska had undergone a laparoscopic or keyhole surgery on January 13.

He said: “It is less severe than major surgery.”

The expert said Puska was given morphine but this would have been out of system by the time of the admission at approximately 6.30pm the next day.

He said the morphine was essentially a painkiller that would have some anesthetic use as well.

Prof Ryan said Puska was also given the highly potent opioid fentanyl and a “very short-acting anesthetic”.

The witness said Puska was also given an antibiotic as part of standard procedure to prevent infection.

He said this antibiotic would have had “absolutely” no effect on mood.

Prof Ryan said these drugs were not active in his system at the time of the alleged admission the next day.

He said Puska was awake shortly after the surgery and the anaesthetic had worn off.

He said the drugs would have been “completely eliminated” well before 6pm on January 14.

Prof Ryan said he examined the notes from Puska’s observation in the highly controlled post-operative environment.

He said patients, their vital signs and their pain are monitored very closely in this environment.

Prof Ryan said Puska was also given oxycodone and this was the only drug that could have had a possible influence on his mood and behaviour.

He said this is an analgesic opioid, similar to morphine, which was developed in 1917. He said it is used for post-operative pain control and the side effects are well documented and well known.

The witness said the drug has addictive properties and that it can repress the respiratory system.

Prof Ryan said other side effects include the inducement of nausea and vomiting, itching and constipation. He said it can produce some dizziness at higher doses.

Prof Ryan said the side effects are dose-related and occur more frequently with higher doses.

“You mainly only see these side effects at very high doses.”

He said a dose is determined, to some extent, by the patient and their pain.

Puska was given 1mg of oxycodone intravenously at 11.47pm and 11.52pm after keyhole surgery on January 13.

He was given a 5mg oxycodone tablet orally at 3.42am on January 14. He was given a further 5mg tablet at 11.38am.

Asked by senior counsel for the prosecution Anne-Marie Lawlor if the 3.42am oxycodone tablet would be gone from Puska’s system at this stage, Prof Ryan said most of it would be gone and that it would have “gone to a non-therapeutic level”.

Puska was given two further 5mg tablets of oxycodone at 3.32pm and 4.05pm.

Prof Ryan said the half life of oxycodone was between three and five hours, with some variability.

He agreed with Judge Tony Hunt when asked if the drug would be “basically gone for all intents and purposes” after four half lives.

Prof Ryan said the maximum amount of oxycodone in Puska’s system at 6pm before the alleged admission would be 8.25mg.

He referenced a study, which was done on “normal volunteers” outside a post-operative situation, that he said showed there were no effects seen in mood and behaviour on people given less than 10mg of oxycodone.

Prof Ryan told the court that the levels of oxycodone given to Puska were “very much” on the lower end of the scale.

He said Puska was given 5mg tablets and the drug also comes in 10mg and 20mg tablets.

Ms Lawlor asked if some patients could be administered up to 400mg of oxycodone.

He said a patient could be given that level but that would be “very high”.

Prof Ryan also said paracetamol and ibuprofen would not have had an effect on Puska’s behaviour.

The witness told the court there was “no evidence to suggest his admission was related to any drug”.

He said there was no evidence from the medical notes that Puska could be said to be sedated.

Under cross-examination, Prof Ryan said he was not a clinical doctor and had no experience in treating patients on a ward.

For the defence, Seoirse S O Dunlaing asked if Prof Ryan had relied on garda notes of their interactions with Puska, including that the defendant appeared distressed at one stage and an alarm had activated.

Prof Ryan said he did not examine the detail of the garda records and that was not his expertise.

Ms Lawlor asked the professor if he had ever heard of anyone confessing to a murder on a dosage of less than 10mg of oxycontin.

Prof Ryan replied: “No.”

The trial continues on Wednesday.

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