“Subs” is street slang for Suboxone and similar medications that combine two active ingredients: buprenorphine and naloxone. These prescription drugs are used to treat opioid addiction, helping people stop using heroin, fentanyl, or prescription painkillers without going through severe withdrawal. Subs are one of the most effective tools available for opioid use disorder, and they can be prescribed by any doctor with standard controlled-substance prescribing authority.
What’s Actually in Subs
Every sub contains two drugs working together. Buprenorphine is the primary active ingredient. It’s a partial opioid, meaning it activates the same brain receptors that heroin or fentanyl would, but only partially. It takes the edge off cravings and withdrawal symptoms without producing the intense high of stronger opioids. The second ingredient, naloxone, is an opioid blocker. When a sub is taken as directed (dissolved under the tongue), naloxone has very little effect. But if someone tries to crush and inject the medication to get high, the naloxone activates and triggers immediate, intense withdrawal symptoms. It’s essentially a built-in deterrent against misuse.
How Buprenorphine Works in the Brain
Full opioids like heroin flood the brain’s opioid receptors and produce a powerful rush. The more you take, the stronger the effect, which is what makes overdose so easy. Buprenorphine works differently. It binds to those same receptors with strong grip but only partially activates them. This creates what pharmacologists call a “ceiling effect”: after a certain dose, taking more doesn’t increase the high or the respiratory depression that causes overdose deaths. That ceiling is what makes subs substantially safer than methadone or other full opioids used in addiction treatment.
Because buprenorphine clings to opioid receptors so tightly, it also blocks other opioids from attaching. If someone takes heroin while on a stable dose of subs, they’ll feel little to no effect from the heroin. This makes relapse less rewarding, which over time helps break the cycle of compulsive use.
How Subs Are Taken
The most common form is a thin film or tablet placed under the tongue, where it dissolves over several minutes. This is a daily medication that most people take at home. For people who struggle with taking a daily dose or who want a longer-acting option, there’s also a monthly injection (brand name Sublocade) given by a healthcare provider under the skin. The injection delivers a steady dose of buprenorphine over four weeks, removing the need to remember a daily pill.
How Well Subs Work
Staying on buprenorphine long enough matters significantly. A large multi-site study found that people who stopped treatment between three and six months had nearly three times the risk of opioid overdose compared to those who stayed on for more than a year. This doesn’t mean everyone needs to be on subs forever, but shorter courses carry measurably higher risk. Many addiction specialists now treat opioid use disorder as a chronic condition, similar to diabetes or high blood pressure, where ongoing medication is the standard rather than the exception.
Buprenorphine was the first medication for opioid addiction that could be prescribed in a regular doctor’s office rather than requiring daily visits to a specialized clinic (the way methadone does). This made treatment far more accessible, especially in rural areas where methadone clinics are scarce.
Who Can Prescribe Them
Until recently, doctors needed a special federal waiver to prescribe buprenorphine, and they were limited in how many patients they could treat. That changed in 2023 when Congress eliminated the waiver requirement entirely. Now any practitioner with a standard DEA registration that covers Schedule III medications can prescribe buprenorphine for opioid use disorder, with no cap on the number of patients. The only new requirement is that providers applying for or renewing their DEA registration complete at least eight hours of training on substance use disorders.
Side Effects
Subs are generally well tolerated compared to other opioid medications. The most commonly reported side effects include constipation, nausea, headache, and skin irritation. In long-term studies, these tend to occur at low rates, each affecting roughly 1 to 2 percent of patients.
One side effect that gets less attention is dental damage. In 2022, the FDA issued a formal warning after identifying 305 reports of serious dental problems in people using buprenorphine products dissolved in the mouth. These included tooth decay, cavities, oral infections, and tooth loss, sometimes in people who had no prior dental issues. The problems typically appeared about two years into treatment, though they showed up as early as a few weeks in some cases. Tooth extraction was the most common treatment needed, reported in nearly a quarter of those cases.
The likely cause is that the medication changes the acidity in the mouth while it dissolves. If you take sublingual buprenorphine, rinsing your mouth with water after the medication fully dissolves can help protect your teeth. The FDA recommends swishing water gently around your teeth and gums, then waiting at least an hour before brushing to avoid damaging enamel while your mouth is still acidic.
Why Subs Have Street Value
Subs do circulate on the black market, which is part of why people search for them by their slang name. Some people buy them to self-treat withdrawal when they can’t access a doctor. Others use them to bridge gaps between getting other opioids. While buprenorphine can be misused, its ceiling effect makes it far less dangerous than heroin or fentanyl. Most addiction researchers view diverted buprenorphine as a sign of unmet treatment demand rather than a recreational drug problem. People obtaining subs on the street are, more often than not, trying to manage withdrawal or reduce their use of more dangerous drugs on their own.