Heroin overdose deaths doubled over the past three years in New York City -- from 209 in 2010 to 420 last year, according to statistics released Thursday by the city health department.
The fatal overdoses in 2013 were the most in the five boroughs since 2003, records show.
The increase reflects a national trend toward greater heroin use as opioid pain pills -- which offer a similar high -- become harder to get due to tougher regulations and a dwindling street supply, experts say.
Heroin was the narcotic most frequently cited in city overdose deaths in 2013, with officials detecting it in 54 percent of 782 drug fatalities, records show.
Nearly all of the city's overdose deaths last year involved more than one substance, the health department said, meaning other drugs were present in the blood in addition to heroin.
On Long Island, more than 220 heroin-related deaths were recorded in 2012 and 2013 -- the most tallied during a two-year-period, records show.
Experts say the data released by the city is further evidence of an opiate crisis plaguing the region. Many users are becoming addicted to high-priced pain pills before moving on to heroin, which is significantly cheaper, said Dr. Andrew Kolodny, chief medical officer for the multistate Phoenix House Foundation, which helps treat addiction.
"New York [State] should be doing a much better job of expanding access to treatment," Kolodny said, adding that the distinctions between heroin and opioid pain pill overdoses matter little. "It's essentially the same drug people are dying from."
The city data showed higher rates of heroin overdose deaths among white residents, affluent users and Hispanic users in the Bronx. Queens saw the largest increase in heroin-related deaths, rising from 53 in 2012 to 81 last year, records show.
Profits for those who make money off heroin in the region have soared because of increased demand, an abundance of high-quality product flowing into the United States through Mexico, and low wholesale prices, authorities said.
Authorities said affluent New Yorkers across the state are using heroin at higher rates, a trend exemplified by the overdose death in February of Oscar-winning actor Philip Seymour Hoffman in his Greenwich Village apartment.