Buprenorphine/Naloxone works by partially activating the same brain receptors that opioids target, which reduces cravings and withdrawal symptoms without producing a significant high.

If you've been prescribed Buprenorphine/Naloxone (Suboxone, Zubsolv, or Bunavail) or you're considering it, understanding how it works can help you feel more confident about your treatment. This guide explains the science behind the medication in simple terms — no medical degree required.

What Buprenorphine/Naloxone Does in Your Body

To understand how Buprenorphine/Naloxone works, it helps to know a little about opioid receptors.

Your brain has receptors — think of them like locks on a door. Opioids like Heroin, Fentanyl, or Oxycodone are like keys that fully open those locks, flooding your brain with signals that produce pain relief, euphoria, and eventually dependence.

Buprenorphine: The Partial Key

Buprenorphine is a partial agonist at the mu-opioid receptor. That means it fits into the same lock, but only turns it partway. Here's what that does:

• Reduces cravings — by partially activating the receptor, Buprenorphine satisfies enough of the brain's need that you don't feel driven to use other opioids
• Prevents withdrawal — it provides enough stimulation to keep withdrawal symptoms at bay
• Limits euphoria — because it only partially activates the receptor, it doesn't produce the intense high that full agonist opioids do
• Has a "ceiling effect" — after a certain dose, taking more Buprenorphine doesn't increase its effects. This ceiling makes it much harder to overdose on Buprenorphine alone compared to full opioids.

Buprenorphine also acts as an antagonist at kappa-opioid receptors, which may help improve mood and reduce the dysphoria (feeling of unease) that often comes with opioid withdrawal.

Naloxone: The Safety Net

Naloxone is an opioid antagonist — it blocks opioid receptors entirely. It's the same drug used in Narcan to reverse opioid overdoses.

So why is it included in a medication for people with opioid dependence? Here's the key: when you take Buprenorphine/Naloxone under the tongue as directed, Naloxone has almost no effect. It has very poor bioavailability when absorbed through the mouth, meaning your body barely absorbs it.

However, if someone tries to dissolve the medication and inject it, the Naloxone becomes fully active. It blocks the opioid receptors and can trigger immediate, intense withdrawal symptoms. This makes the combination much harder to misuse than Buprenorphine alone.

Think of Naloxone as a built-in deterrent — it's there as a safety feature, not as an active treatment component when taken correctly.

How Long Does It Take to Work?

Buprenorphine/Naloxone begins working within 30 to 60 minutes of placing the film or tablet under your tongue. Most people start feeling relief from withdrawal symptoms within the first hour.

During induction (your first dose), your doctor will have you wait at least 12 hours after your last opioid use before taking Buprenorphine/Naloxone. This waiting period is critical — taking it too soon can cause precipitated withdrawal, where the Buprenorphine displaces the opioid still on your receptors and triggers sudden, intense withdrawal symptoms.

How Long Does It Last?

One of the advantages of Buprenorphine is its long duration of action. A single dose lasts approximately 24 to 72 hours, depending on the dose and individual factors. This is because Buprenorphine binds very tightly to opioid receptors and dissociates slowly.

For most patients on maintenance therapy, once-daily dosing is sufficient. Some patients on stable, higher doses may even be prescribed every-other-day dosing under medical supervision.

What Makes Buprenorphine/Naloxone Different from Similar Medications?

There are several medications used to treat opioid use disorder. Here's how Buprenorphine/Naloxone compares:

Vs. Methadone

Methadone is a full opioid agonist — it fully activates the mu-opioid receptor. It's highly effective but must be dispensed through specialized opioid treatment programs (OTPs), typically requiring daily clinic visits, at least initially. Buprenorphine/Naloxone can be prescribed in a regular doctor's office or via telehealth, offering much more flexibility. Methadone also carries a higher risk of overdose because it lacks the ceiling effect.

Vs. Naltrexone (Vivitrol)

Naltrexone is a full opioid antagonist — it completely blocks opioid receptors. It's available as a monthly injection (Vivitrol) and has no abuse potential. However, patients must be fully detoxed from all opioids (typically 7 to 14 days) before starting Naltrexone, which is a significant barrier for many people. Buprenorphine/Naloxone can be started much sooner — usually within 12 to 24 hours of last use.

Vs. Sublocade and Brixadi

Sublocade and Brixadi are extended-release Buprenorphine injections given monthly (or weekly for Brixadi). They eliminate the need for daily sublingual dosing. However, patients typically need to be stable on sublingual Buprenorphine/Naloxone first before transitioning. These are good options for people who prefer not to take a daily medication.

For more on treatment alternatives, see our guide on alternatives to Buprenorphine/Naloxone.

Final Thoughts

Buprenorphine/Naloxone is an elegantly designed medication. The partial agonist (Buprenorphine) manages cravings and withdrawal while limiting euphoria and overdose risk, and the antagonist (Naloxone) deters misuse. Together, they create a medication that's effective, safer than full opioid agonists, and accessible through regular healthcare settings.

Understanding how your medication works can make you a better partner in your own treatment. If you have questions about your specific dose or treatment plan, talk to your prescriber.

Need to find Buprenorphine/Naloxone at a pharmacy near you? Use Medfinder to check availability.