After attending a rugby team party where alcohol was plentiful, 16-year-old Joseph Loudon died sometime before dawn May 24. Drinking was a suspected cause of death.
But when the coroner's report came back, Loudon's blood alcohol level was well below the level that constitutes drunken driving.
Instead, the coroner's report said the cause of death was a mixture of alcohol and papaverine, according to a report released last week to the San Francisco Chronicle, or a prescription drug used to treat erectile dysfunction (ED), among other things. The combination of alcohol and papaverine caused Loudon to vomit and choke to death.
In addition to highlighting the pitfalls behind abuse of prescription drugs, the incident also raises questions about why Loudon used the drug in the first place, whether he used it knowingly and whether it was even being used in a way that would deliver the intended effects.
According to Jimmy Lee, a spokesman for the Contra Costa County Sheriff's Department, which includes the county coroner's office, "Whether it was injected or orally taken, we don't know."
The Loudon family declined to speak with ABC News.
Knowledge of how the drug was taken may shed some light on the mystery surrounding Loudon's death.
Papaverine, like morphine and codeine, comes from opium poppy, although it has different effects on the body. It is used to relax muscle tissue and dilate blood vessels, and therefore, it can be used as an erectile dysfunction drug, injected directly into the penises of elderly men with the disorder.
While the drug has been used on blood vessels since before World War II, it received renewed interest when it was discovered in the 1980s that it could help induce erections. However, according to the Food and Drug Administration, the drug has no approved uses.
While papaverine appears in tablet and extended-release capsule forms, those tend to be used for enlarging blood vessels in a hospital setting.
"Papaverine right now is not used very often," said Dr. Tom Lue, a professor of urology at the University of California, San Francisco Medical Center. "I don't even think the tablet form is available as a medical use in the United States."
While oral forms are available for sale online, that is often not the source for teenagers when they abuse prescription drugs, according to Kevin Conway, deputy director of the National Institute on Drug Abuse's division of epidemiology, services and prevention research.
"Probably the primary source kids rely on is their friends," he said. "Kids are not obtaining the drugs very commonly from online sources."
Lue noted that even if men could obtain the tablets, it would not enable an erection.
"It doesn't work for the penis if you take it by mouth. What you do is you will get [the] stomach dilated and you get a bloated stomach," he said.
Other physicians confirmed that assessment.
"I don't know a single [ED patient] who's taking papaverine [in oral form]," said Dr. David Gentile, a urologist with the University of Rochester. "My guess is whoever had this drug did not get it from a urologist."
While suspicions remain that papaverine was used to obtain an erection in this case, it is unlikely that it will replace more commonly used erectile dysfunction drugs such as Viagra, Levitra and Cialis, even as a recreational drug.
"Those are much easier to get, and also, [they're] effective," said Lue.