While the cause of Whitney Houston's death may not be known for weeks, the 48-year-old singer reportedly had a prescription for Xanax and a history of alcohol and drug abuse, checking into rehab centers at least three times during her career.
Found dead in a bathtub Feb. 11, one prevalent theory for her cause of death is a drug/alcohol combination overdose.
Toxology reports can take weeks to complete, but it is known that a combination of Xanax and alcohol can be deadly, said Dr. Marvin Seppala, chief medical officer at Hazelden, a preeminent treatment center for alcohol and other drug addiction.
The anti-anxiety drug alprazolam, the generic name for Xanax, is classified as a benzodiazepine. Benzodiazepines are sedatives that work by binding to part of the brain's natural tranquilizers, or gamma amino butyric acids, to increase your natural calming ability.
They work quickly, often in 15 minutes -- and are highly addictive. The effects last just a few hours. Alprazolam is also the eighth-most prescribed drug in the United States in 2010, according to the New York Times.
"It's often used for stage fright or other types of anxiety; however, it's abused a great deal and has the potential for addiction," Seppala said, especially if someone has a genetic predisposition for addiction. "Tolerance develops quickly if it's used on a regular basis."
When mixed with alcohol, the anti-anxiety drug's effects can be intensified, resulting in greater intoxication. Another risk, though, is respiratory depression. Both substances can cause your heart rate to slow and impair your breathing, putting those who overdose at risk of death.
The combination of alcohol and benzodiazepines have a calming function in the brain, slowing down some of the brain's functions, Seppala said.
"They cause the control mechanism of the respiratory system to slow down and ultimately stop," he said.
Most patients checking in for rehab from the drug fall into two groups, Seppala said:
"One group never uses it addictively, but needs help getting off because they've built up tolerance," he said. "The other group is mixing it with all kinds of other stuff: opiates, marijuana, alcohol, and that complicates the withdrawal and the whole picture."
The longer Xanax and similar drugs are taken, the less effective they become. Withdrawal effects are unpleasant, including headaches, insomnia, depression -- and more nervousness.
Abuse of alprazolam has become so rampant and demand for the drug so high that a clinic in Louisville, Ky., decided to stop writing new prescriptions for the drug last September. And in 2010, the Centers for Disease Control and Prevention reported an 89 percent increase in emergency room visits nationwide related to non-medical benzodiazepine use between 2004 and 2008.
The increase in Xanax prescriptions, Seppala said, can be attributed to patients expecting medication and doctors being willing to hand it out.
There are better medications for stage fright, Seppala said.
"There's a type of antihypertensive beta blockers that are non-addicting and reduce anxiety,” he said. "They're used for performance anxiety; for example, when a cellist or violinist who plays great in practice but develops a slight tremor on stage because of anxiety."
Houston had been hoping to revive her career this year with a possible comeback album, the New York Times reported. In the days before her death, her behavior appeared erratic, wearing mismatched clothes with wet hair and bursting on the set of a television interview with Clive Davis. Slurred speech and behavior often associated with being drunk are also typical of high doses of Xanax, Seppala said.
"I know there are reports that she maybe was drowned, or did she overdose, but we won't make a final determination until all the tests are in," said Ed Winter of the Los Angeles coroner's office at a news conference on Sunday.