According to the Center for Disease Control (CDC), the rate of heroin-related overdose deaths nearly quadrupled in the United States from 2002 to 2013. The World Health Organization estimates that 9.2 million people use heroin globally. Yet, despite the prevalence of heroin addiction and overdose deaths, the two drugs primarily used to treat heroin addiction by easing withdrawal symptoms, methadone and buprenorphine (the combination of buprenorphine and naloxone, which helps prevent misuse, is sold as Suboxone) are somewhat controversial. Methadone provides a high similar to that provided by heroin and is similarly addictive, and doctors currently face caps on the amount of buprenorphine prescriptions they can write.

Many treatment centers in the United States rely on an abstinence-only approach to treating addiction, which often leads to high rates of dropouts, the Huffington Post reported in January. In Kentucky, for instance, the dropout rates are as high as 75 percent. Individuals who drop out of treatment centers are at high risk for fatal overdoses if they relapse, as they have a lower tolerance for heroin.

Many heroin addicts over the last few decades first became addicted to prescription opioid painkillers such as OxyContin. According to the National Survey on Drug Use and Health, people who are addicted to opioid painkillers are 40 times more likely to become addicted to heroin. The increased prevalence of heroin overdoses has led to a gradually awakening public consciousness of America’s heroin epidemic and may lead to increased treatment options for addicts. In May, presidential candidate Hillary Clinton vowed to tackle substance abuse and mental health issues in her campaign.

What is methadone?

Methadone, which was introduced in the United States in 1947, is a synthetic opiate derivative that activates mu receptors on nerve cells. Methadone (like heroin) is a full opioid agonist, meaning it affects mu receptors until all have been fully activated.

“One result of the activation of mu opioid receptors is the release of dopamine, a neurotransmitter that is central to our reward system, and thus euphoria is experienced by the individual,” Dr. Andrew Coop, Professor of Pharmaceutical Sciences at the University of Maryland, told ATTN: in June. “This is the reason why taking heroin gives its high. However, it is the continued, sustained use that causes adaptations to the biological systems resulting in 'addiction.' That is, the body responds to the presence of the drug so that the presence of the drug is required for normal functioning."

In addition to treating heroin addiction, methadone may also be prescribed for chronic pain. Methadone can lead to addiction, though, and is far from risk-free: According to a CDC report from 2013, methadone contributes to around 5,000 deaths per year in the United States, and over 30 percent of prescription painkiller deaths involve methadone, though methadone accounts for just 2 percent of painkiller prescriptions. Methadone maintenance is also expensive: According to a Washington Post article from January 2015, methadone can cost up to $3,500 per patient annually.

In May, ATTN: spoke with journalist Sam Quinones, author of “Dreamland: The True Tale of America’s Opiate Epidemic,” about methadone’s potential to help end the heroin epidemic. In many ways, methadone is a much better alternative to legalized heroin, Quinones said, even though methadone is still addictive.

“Methadone has no needles [and is distributed as a liquid or a tablet]. You go once a day. Methadone is also far more calming of a drug. Heroin spikes and crashes like crack. It’s up and down all day long. Heroin is such a great underworld business because you are always buying it, every day you’ve got to buy it four or five times a day. You’re constantly consumed with finding it, and taking it, and finding it again and taking it.”

What is buprenorphine?

Buprenorphine, which is taken as a tablet under the tongue once a day, was approved to treat opioid addiction in the United States in 2002. Though it’s even costlier than methadone, it may be a safer alternative.

“As buprenorphine is a partial agonist, meaning there is a ceiling to its effects, respiratory depression (the major reason for overdose death to opioids) does not reach critical levels with buprenorphine,” Coop previously told ATTN:. “Thus, a patient taking buprenorphine is far less likely to overdose than a patient taking heroin or a prescription full agonist (morphine, oxycodone). As such, I have always been in favor of buprenorphine as a safe treatment agent.”

Currently, doctors are allowed to treat only 30 patients with buprenorphine in the first year after they have been certified to prescribe it and 100 patients each subsequent year. The Recovery Enhancement for Addiction Treatment Act (TREAT Act), a Senate bill backed by Sen. Edward Markey (D-Mass.) and Sen. Rand Paul (R-Ky.), proposes raising the initial cap for buprenorphine prescriptions from 30 to 100 patients.

The bill also proposes that nurse practitioners and physicians' assistants who meet certain criteria be allowed to treat up to 100 patients annually and recommends that doctors (provided they are either substance abuse specialists or have completed training) have the option to request removal of the cap after one year.

Methadone versus buprenorphine

A study published in 2012 in the Journal of Neurosciences in Rural Practice found that “despite obvious benefits due to its unique pharmacotherapy (e.g. greatly reduced risk of overdose), buprenorphine has largely failed to overtake methadone in managing opioid addiction."

The researchers found that buprenorphine, because of its “weaker efficacy,” might be better suited for patients with mild-moderate dependence, while methadone can more successfully treat higher levels of dependence. According to the study, both methadone and buprenorphine were successful in suppressing heroin use among addicts who stay in the trials, but methadone, which provides a greater high, was more successful at keeping patients in the trials.

"Buprenorphine is probably the safer agent,” the study’s authors concluded. “However, its relative advantage over methadone in these safety domains is somewhat tempered by the emerging evidence of problematic diversion [when prescribed drugs are sold or distributed illegally] and the risks associated with the intravenous use of crushed tablets."

A report published in Addiction in 2013 corroborated the conclusion that methadone is more successful at retaining patients in treatment, yet found that buprenorphine provision was correlated with “lower continued use of illicit opioids.”

Individuals who had been treated with both methadone and buprenorphine are more likely to abuse other substances, such as alcohol or cocaine, than individuals treated with only methadone or buprenorphine, according to a study published in February 2015.

Further research may help to clarify the relative strengths and weaknesses of each drug and to improve upon their potential to treat heroin addiction. Removing, or at least altering, the buprenorphine cap, and making the drug more accessible to those who need it, is an important step towards treating the chemical dependency of addicts, rather than treating their addiction as a moral failing.