A 19-year-old British student who jumped from a plane during a biology internship in Madagascar was “mumbling” and “pretty incoherent” two days before her death — possibly due to the effects of prescription meds, according to her family.

Alana Cutland was on her way back home after cutting short her six-week research trip when she suddenly plunged more than 3,600 feet from a small Cessna into a remote forest on July 25.

The pilot and a friend of Cutland’s from the UK tried in vain to prevent the Cambridge University student from jumping. Her body has not yet been recovered.

Local police chief Sinola Nomenjahary has said the young woman, who was studying a rare species of crabs, had been stressed out and suffered five panic attacks during her stay in Madagascar.

Cutland’s uncle said she became ill a few days after arriving on the island off East Africa.

“When she spoke to her mother on the phone two days before the accident, she was mumbling and sounded pretty incoherent,” Lester Riley, 68, told Mail Online.

Authorities are investigating whether Cutland suffered a reaction to anti-malaria drugs, the news outlet reported, adding that in very rare cases, some of the medications, including lariam and Malarone, can cause paranoia, depression, hallucinations and even suicidal thoughts.

“We think she had suffered a severe reaction to some drugs but not anti-malaria ones because she had taken those on her trip last year to China without any side effects,” the retired electrician said.

“What happened, the family believe, was a tragic accident, not a suicide, and we are utterly heartbroken. Alana had everything to live for, nothing to die for, and we don’t think for a moment she deliberately took her own life,” he added.

“She was hallucinating, she was unwell, something had made her ill, it must have been a reaction to medication.”

Meanwhile, the pilot described how he and Ruth Johnson, 51, battled for five minutes to try to prevent Cutland from leaping from the aircraft before she slipped from their grasp.

Mahefa Tahina Rantoanina, 33, told The Sun that Cutland remained “completely silent” during the struggle.

“I had just taken off and I was still climbing when all of a sudden there was a rush of wind and Ruth started screaming,” he told the newspaper.

“I turned round and saw Alana hanging out of my plane. I immediately leveled the aircraft to try and keep us on course, then I reached over and held the door,” he continued.

“I was trying to pull it shut while Ruth was holding on to Alana’s leg. The plane stayed level, there was no rocking but it was very noisy from the wind,” the pilot said.

“I was trying to fly and stop her from falling at the same time. I was absolutely terrified, we all were. Ruth and I were shouting at her to come back inside the plane.

“But for the whole time Alana did not say a word, she just struggled to get away from us. I have no idea why she opened the door but she did. She opened the door and she jumped. The door did not open itself,” he said.