A wave of overdoses along the East Coast linked to fentanyl-laced heroin has led to speculation that Philip Seymour Hoffman was killed by a similar blend. The envelopes found next to Hoffman's body and the details of the other deaths offer no evidence — so far — that it was.

How heroin is sold

AP

Heroin is often packaged in small packages made of a wax-paper-like material called "glassine." The picture at right is of empty glassine envelopes seized in December 2013. You can see that they are labeled with a stamp identifying the particular product; the envelopes at right were for a mix called "Obamacare." (Which is largely why they made the news at that point.) A former heroin addict created a fascinating index of used glassine packages that gives a better sense of the diversity of the product. These are brand names, used for marketing.

Mixing heroin with other drugs

Dealers regularly mix the heroin with other substances. After all, cutting the drug (as it's known) extends the number of packages of the drug that can be sold, leading to more profit from the initial batch of heroin. Sometimes the added substances are toxic, sometimes they aren't.

Fentanyl is a prescription narcotic used for pain relief. As Slate notes, it's "cheaper and between 50 to 80 times more potent" than heroin itself, making it both an appealing and dangerous substance to add to heroin. Mixing fentanyl and heroin isn't new, Slate notes, but tends to come in waves as new batches of fentanyl enter the market. When they do, there can be a rash of overdoses, as people administer the same dose of heroin not realizing that it contains a more potent drug.

Why people suspect fentanyl: A number of recent deaths

That's happened recently, with cities from Pittsburgh to Poughkeepsie seeing an increase in overdoses linked to a heroin-fentanyl mixture. At the end of January, the Pittsburgh area had seen 22 deaths linked to the drug. In the same timeframe, there were several deaths in the Hudson River Valley north of New York City. There were another five deaths in Nassau County, New York, linked to the batches of the drug in Pittsburgh.

What's notable about the Nassau County deaths, which were also reported at the end of January, is that they indicate the brand names that were linked to the fentanyl mix from Pittsburgh: "24K," "Theraflu," and "Bud Ice."

The heroin in Hoffman's apartment

According to the New York Post, Hoffman was found with five empty glassine envelopes near his body.

The drug envelopes were marked “Ace of Spades,” which sources said is a brand of heroin that has not been seen on city streets since around 2008 in Brooklyn. … Police later executed a search warrant and found 70 glassine envelopes of heroin inside a desk. In addition to the “Ace of Spades,” investigators also found packages marked “Ace of Hearts” and one with a playing-card jack stamped on it.

Emphasis added. That the packages weren't stamped with any of the brand names found in Nassau or further west doesn't mean that the heroin Hoffman injected wasn't mixed with fentanyl. Police are trying to find the dealer of the drug, both for the obvious reasons and to learn more about its composition. Hoffman's autopsy, being conducted on Monday, should also provide insight.

Heroin overdoses aren't uncommon — and are growing more frequent

DrugAbuse.gov

When Rhode Island had a rash of 19 overdose deaths over two weeks January, it's important to note that only 13 of the deaths were linked to heroin cut with fentanyl. People die of heroin overdoses regularly. According to the Centers for Disease Control, overdose was the leading cause of injury death in 2010 among Hoffman's age group — killing more people than automobile accidents — though most overdoses are not from heroin use. Three-quarters of all overdose deaths were accidental.

Those numbers are increasing. Between 1992 and 2010, death rates from overdose more than doubled. As reported by CNN, the Drug Enforcement Agency's 2013 drug assessment report indicated that overdoses may be on the increase in part because people are switching from prescription drug abuse to using heroin, thanks to an increase in the drug being smuggled into the United States from Mexico. Between 2010 and 2011, for example, heroin overdoses in Minneapolis/St. Paul tripled.

That Hoffman's death coincides with a rash of heroin-fentanyl overdoses is certainly suggestive. But, at this point, it seems most likely that his death was more prosaic: a fairly recently relapsed heroin user taking an overdose of the drug. Which doesn't diminish the tragedy of his death.