A young woman who died at a music festival is believed to be the first person in the world to die after taking the substance 2C-P, a court has been told.

Jurors heard that the drug, which Louella Fletcher-Michie, 24, took at the Bestival event in Dorset, could cause hallucinations and agitation, but experts could find no evidence it had led to a user’s death.

Fletcher-Michie’s boyfriend, Ceon Broughton, 29, is on trial accused of her manslaughter and supplying her with 2C-P. The musician, from Enfield, north London, denies the offences.

Ceon Brougton. Photograph: Finnbarr Webster/Getty Images

The prosecution said Broughton did not immediately seek help for Fletcher-Michie, the daughter of the Holby City actor, John Michie, because he was serving a suspended jail sentence and feared imprisonment.

Jurors have been told Fletcher-Michie screeched like an animal after having a “bad trip”, and scraped thorns across her face and ate twigs.

The forensic pathologist Dr Russell Delaney told Winchester crown court on Wednesday that the synthetic substance could cause “potent hallucinations and agitation”, an abnormally fast heart rate and increased blood pressure, as well as raising body temperature.

He said there had been reports of people in the US being admitted to hospital having taken 2C-P, but they had been saved after being treated with a defibrillator. Delaney said smaller amounts of MDMA and ketamine were also found in Fletcher-Michie’s bloodstream.

The pathologist told the court Fletcher-Michie had cuts and bruises on her arms and legs, as well as bruising to her nose and cuts on her face.

He said: “[Her] agitated behaviour continued over a number of hours ... Her boyfriend describes restraining her and it requiring all his might.”

During his cross-examination of Delaney, Stephen Kamlish QC, representing Broughton, said: “There are no deaths in world literature attributed to 2C-P, a fact which has been fully researched by both the prosecution and defence in this case.”

The toxicologist Dr Stephen Morley told jurors: “As far as I can tell, there has never been a recorded case in scientific literature of 2C-P causing a death.”

Morley added: “We have to be very careful when talking about dosages, but Alexander Shulgin, who created the 2C group drugs and tested them on himself and a small group of colleagues, showed most doses are between six and 10 milligrams.

“He once took a single dose of 16 milligrams and said it was a physical disaster not to be repeated. You can have a very small increase in the amount you take and it can have a very detrimental effect.

“Shulgin’s original work said if you took 10 to 12 milligrams it can have a pleasurable effect, but even a small increase to him had a far more negative effect. A bump up may have a far greater negative effect than a straightforward dosage.”

The trial continues.