No, naloxone does not work on benzodiazepines. Naloxone is an opioid-specific reversal drug, and it has zero effect on a benzodiazepine overdose. The two drugs act on completely different receptor systems in the brain, so naloxone simply cannot reverse the sedation or respiratory depression caused by benzodiazepines alone. SAMHSA states this explicitly: “naloxone has no effect on non-opioid overdoses, such as those involving cocaine, benzodiazepines, or alcohol.”
Why Naloxone Only Works on Opioids
Naloxone reverses an opioid overdose by competing for the same parking spots on brain cells. Opioids like fentanyl, heroin, and prescription painkillers bind to opioid receptors (primarily the mu receptor) and slow breathing to dangerous levels. Naloxone has a higher affinity for those same receptors, so it knocks the opioid molecules off and blocks them from reattaching. Breathing returns to normal, often within minutes.
Benzodiazepines don’t touch opioid receptors at all. They work on an entirely different system: GABA receptors. Specifically, benzodiazepines bind to a site on the GABA-A receptor at the junction between two protein subunits, enhancing the calming signals that GABA normally produces. Because naloxone only targets opioid receptors, giving it to someone experiencing a pure benzodiazepine overdose accomplishes nothing. It’s like using a car key to unlock a house door.
What a Benzodiazepine Overdose Looks Like
A pure benzodiazepine overdose looks different from an opioid overdose, which matters when you’re trying to figure out what someone took. The hallmark of benzodiazepine toxicity is central nervous system depression (deep sedation, slurred speech, loss of coordination, or unresponsiveness) with relatively normal vital signs. Heart rate, blood pressure, and breathing are often close to normal ranges, and fatal outcomes from benzodiazepines alone are uncommon.
Opioid overdoses, by contrast, produce a distinctive triad: pinpoint pupils, severely slowed or stopped breathing, and deep unconsciousness. The breathing suppression is what kills. If someone is unresponsive and barely breathing with tiny pupils, opioids are the likely culprit, and naloxone is the right call.
The Benzodiazepine-Specific Antidote
Benzodiazepines do have their own reversal agent: flumazenil. It works by the same competitive principle as naloxone, just on a different receptor. Flumazenil binds to the benzodiazepine site on GABA-A receptors and displaces the benzodiazepine molecules, preventing them from enhancing GABA signaling. It’s FDA-approved for reversing benzodiazepine overdose and for reversing sedation after medical procedures that used benzodiazepines.
However, flumazenil is used far less freely than naloxone, and for good reason. In people who have been taking benzodiazepines regularly, flumazenil can trigger sudden withdrawal, which can cause life-threatening seizures. This makes it risky in emergency settings where the patient’s medication history is unknown. Because of this seizure risk, flumazenil is most commonly reserved for specific situations: accidental ingestion by children, or reversing oversedation that was caused by a known benzodiazepine dose during a medical procedure. It is not something bystanders carry the way they carry naloxone kits.
Why This Question Matters in Mixed Overdoses
The reason this question comes up so often is that opioids and benzodiazepines are frequently taken together, whether intentionally or because street drugs contain unexpected substances. When combined, the two drug classes produce synergistic respiratory depression, meaning the breathing suppression is worse than either drug would cause alone. CDC data from 2024 show that 73.4% of fatal overdoses involved at least one opioid, and benzodiazepines remain a significant co-contributor at a rate of about 18 per 100,000 people across reporting jurisdictions.
In a mixed overdose involving both opioids and benzodiazepines, naloxone will reverse the opioid component. This can be enough to restore breathing, since opioids are typically the primary driver of respiratory failure. But naloxone will not touch the sedation or other effects caused by the benzodiazepine. The person may still be groggy, confused, or unresponsive even after naloxone is given, because the benzodiazepine is still active in their system.
SAMHSA guidelines recommend administering naloxone whenever an opioid overdose is suspected, even if other substances might be involved. If the person doesn’t respond, that’s a signal the problem may not be opioid-related. In all cases, supporting the person’s breathing (rescue breaths, calling 911) takes priority, especially when naloxone doesn’t produce a prompt response.
What to Do If You’re Unsure What Was Taken
If you find someone unconscious and you don’t know what they took, giving naloxone is still the right move. It won’t help a benzodiazepine overdose, but it won’t cause harm either. The only people who experience negative effects from naloxone are those who are physically dependent on opioids, in whom it triggers uncomfortable but non-fatal withdrawal symptoms like nausea, vomiting, and agitation.
If naloxone doesn’t improve the person’s condition within two to three minutes, the overdose is likely caused by something other than opioids, or the person is experiencing a non-overdose medical emergency. Either way, 911 should already be called. Continue supporting their breathing and keep them on their side to prevent choking. Emergency medical teams have access to flumazenil and other interventions that aren’t available outside a hospital setting.