Suboxone contains two active ingredients: buprenorphine and naloxone, combined in a 4:1 ratio. Buprenorphine is a partial opioid that reduces cravings and withdrawal symptoms, while naloxone is an opioid blocker included to discourage misuse. The medication was approved by the FDA in October 2002 for treating opioid addiction and remains one of the most widely prescribed treatments for opioid use disorder.
The Two Active Ingredients
Buprenorphine is the primary therapeutic ingredient. It attaches to the same receptors in the brain that opioids like heroin or oxycodone target, but it activates them only partially. This partial activation is enough to ease withdrawal symptoms and reduce cravings without producing the intense high of full opioids. Buprenorphine also binds to those receptors extremely tightly, which means it can block other opioids from having their usual effect if someone uses them while on Suboxone.
Naloxone is the second ingredient, and its role is more nuanced than most people realize. When you take Suboxone as directed (dissolved under the tongue), naloxone is poorly absorbed into the bloodstream. It’s essentially inactive in that form. But if someone were to crush and inject the film, naloxone enters the bloodstream at full strength, blocks opioid receptors, and can trigger immediate withdrawal. This makes naloxone an abuse deterrent rather than a treatment ingredient. Buprenorphine has roughly 10 times the binding strength of naloxone at opioid receptors, so when both are absorbed slowly through the mouth’s lining, buprenorphine wins the competition and naloxone has little practical effect.
Available Dosage Strengths
Suboxone sublingual film comes in four strengths, all maintaining that consistent 4:1 ratio of buprenorphine to naloxone:
- 2 mg / 0.5 mg
- 4 mg / 1 mg
- 8 mg / 2 mg
- 12 mg / 3 mg
The first number is buprenorphine, the second is naloxone. Most people stabilize on a daily dose somewhere between 8 mg and 16 mg of buprenorphine, though individual needs vary widely.
Inactive Ingredients in the Film
Beyond the two active drugs, the thin orange film is built from several inactive ingredients that hold it together, help it dissolve, and make it tolerable to keep under your tongue. The full list includes polyethylene oxide (provides the film’s structure), hydroxypropyl methylcellulose (helps it dissolve evenly), maltitol and acesulfame potassium (sweeteners), lime flavor, citric acid, sodium citrate, FD&C yellow #6 (the dye responsible for the film’s orange color), and white ink used for printing on the film.
These ingredients are worth knowing if you have allergies or sensitivities to food dyes or artificial sweeteners. Maltitol, for instance, is a sugar alcohol that occasionally causes digestive discomfort in people who are sensitive to it, though the amount in a single film is very small.
How Buprenorphine Works in the Body
Once the film dissolves under your tongue, buprenorphine absorbs through the mucous membranes and enters the bloodstream. It reaches the brain and latches onto opioid receptors with unusually strong binding and slow release. This is why it works for a full day on a single dose. The elimination half-life of buprenorphine from a sublingual film is roughly 31 to 35 hours, meaning it takes that long for your body to clear just half the dose. In practice, this long half-life creates a steady, even effect that prevents the peaks and valleys of shorter-acting opioids.
People with liver disease process buprenorphine more slowly. In moderate liver disease, the half-life increases by about 35%, and in severe liver disease by roughly 57%. This matters because the liver is the primary organ responsible for breaking buprenorphine down.
Why Both Ingredients Are Combined
Buprenorphine alone (sold under the name Subutex) is effective for treating opioid dependence. The addition of naloxone doesn’t improve the medication’s therapeutic effect when taken correctly. Its sole purpose is deterring injection misuse. When dissolved under the tongue, naloxone has very low bioavailability, meaning almost none of it reaches the bloodstream in active form. The body simply doesn’t absorb it well through oral or sublingual routes. Injected directly into a vein, however, naloxone is fully active and overpowers buprenorphine’s effects, triggering rapid withdrawal symptoms like nausea, cramping, anxiety, and sweating.
This design creates a built-in safety mechanism. The combination product became the standard formulation for most patients precisely because it reduces the risk of diversion, where medication prescribed for one person is sold or given to someone else who might inject it.
Film Versus Earlier Tablet Form
Suboxone was originally approved as a sublingual tablet in 2002. The sublingual film version came later and is now the dominant form on the market. The film dissolves faster, is harder to tamper with, and delivers more consistent absorption compared to the original tablets. Both contain the same active ingredients in the same ratios, but the film’s inactive ingredient profile (the polyethylene oxide base, lime flavoring, and other components listed above) is specific to the film formulation. Generic versions of both the tablet and the film are now available from multiple manufacturers, and their inactive ingredients may differ slightly while maintaining the same active drug composition.