Key takeaways
- Ketamine is not an opioid. It is classified as a dissociative anesthetic that works primarily on the glutamate system in the brain.
- Ketamine and opioids both affect pain and mood, which is why the question of whether ketamine is an opioid comes up frequently.
- Recent research has explored a possible link between ketamine and the opioid system, but scientists do not consider it an opioid drug.
- When used in a clinical setting for depression or anxiety, ketamine is administered under medical supervision at carefully controlled doses.
- Ketamine carries different risks than opioids, including the potential for dissociation during treatment and psychological dependence with long-term misuse.
Ketamine is not an opioid. It is a dissociative anesthetic that works primarily by blocking NMDA receptors in the brain, a mechanism entirely distinct from how opioid drugs like morphine, oxycodone, or fentanyl work. While both ketamine and opioids can affect pain and mood, they act on different systems, carry different risks, and are used for very different clinical purposes.
If you’ve been exploring ketamine as a treatment for depression, anxiety, or post-traumatic stress disorder (PTSD), you may have wondered: is ketamine an opioid? It’s a reasonable thing to ask. Ketamine has a complicated reputation, and sorting out what it actually is can help you make a more informed decision about whether it might be right for you.
Is ketamine an opioid?
Ketamine is not an opioid. It is a dissociative anesthetic, a type of drug that works by temporarily disrupting certain signaling pathways in the brain. This produces pain relief and, at higher doses, a sense of detachment from one’s surroundings. Its primary mechanism is blocking NMDA receptors, which are part of the brain’s glutamate system.
Opioids work on an entirely different system, binding to opioid receptors to reduce pain and produce sedation. The two drugs take different routes through the brain entirely.
The confusion is understandable. Both ketamine and opioids can relieve pain, and both have histories of recreational misuse. But the underlying biology is quite different, and that difference matters for how each drug is used, regulated, and risks understood.
How does ketamine work in the brain?
Ketamine’s antidepressant effects are thought to come primarily from its action on the glutamate system. When it blocks NMDA receptors, it sets off a chain reaction that encourages the brain to form new neural connections, a process called neuroplasticity. Researchers believe this is why ketamine can relieve depression symptoms within hours, far faster than traditional antidepressants, which typically take weeks to build up in the system.
“What makes ketamine genuinely different from conventional antidepressants — and from opioids — is the speed and the mechanism,” said Joshua Flatow, MD, medical director and chief psychiatrist at Pacific Mind Health. “It’s working on glutamate receptors and promoting neuroplasticity in ways that traditional treatments simply don’t. That’s why it can offer relief for people who haven’t responded to anything else.”
Is there a connection between ketamine and the opioid system?
While ketamine is not an opioid, the science gets a bit more nuanced when it comes to how ketamine’s antidepressant effects work in the brain.
A 2024 study from Stanford University found that ketamine’s antidepressant effects in some participants appeared to be partially mediated by the opioid system, meaning blocking opioid receptors reduced the antidepressant response in those individuals.
This finding generated significant discussion in the research community. However, it does not mean ketamine is an opioid drug. Ketamine does not bind to opioid receptors the way opioids do, does not produce the same respiratory depression that makes opioids so dangerous in overdose, and is not classified as an opioid by the DEA or FDA.
The Stanford findings suggest that the opioid system may play a supporting role in how ketamine’s antidepressant effects unfold in some people, not that ketamine itself is an opioid.
Research in this area is ongoing, and clinicians continue to monitor the evolving science. For now, ketamine remains classified as a Schedule III controlled substance, in a different regulatory category from Schedule II opioids like oxycodone and fentanyl.
How is ketamine different from opioids?
Ketamine and opioids differ in several important ways beyond their mechanism of action.
- Drug classification. Ketamine is a Schedule III controlled substance under the DEA. Most prescription opioids, including oxycodone, hydrocodone, and fentanyl, are Schedule II, indicating a higher potential for abuse and dependence.
- Risk of respiratory depression. One of the most serious risks of opioid use is respiratory depression, the slowing or stopping of breathing that causes overdose deaths. Ketamine does not cause this effect at therapeutic doses. This is why it has historically been used as an anesthetic in emergency medicine settings where other drugs would be too risky.
- Addiction profile. Both ketamine and opioids carry a risk of misuse, but the nature of that risk differs. Opioids are physically addictive. Stopping them abruptly after prolonged use can cause severe withdrawal symptoms. Ketamine dependence tends to be more psychological in nature, and physical withdrawal is generally milder. Misuse, however, can still lead to serious harm, including bladder and urinary tract damage with heavy long-term use.
- Speed of antidepressant effect. Opioids are not used as antidepressants in standard clinical practice. Ketamine’s rapid antidepressant effect — sometimes felt within hours of a single session — is one of the primary reasons it is being used and studied for treatment-resistant depression and other mood disorders.
What does ketamine treatment look like in a clinical setting?
When ketamine is used therapeutically for depression, anxiety, or PTSD, it is administered at carefully controlled doses under medical supervision, a very different context from recreational use or the doses used in surgical anesthesia.
At Pacific Mind Health, ketamine is offered as compounded intranasal ketamine, a format that allows for precise dosing in a clinical setting. Patients are monitored throughout their session and are not permitted to drive afterward. Treatment typically starts with an induction phase with more frequent sessions, followed by optimization and maintenance phases schedule based on individual response.
Spravato® is the FDA-approved nasal spray form of ketamine’s close chemical relative, esketamine. It is approved specifically for treatment-resistant depression and major depressive disorder with suicidal ideation. Unlike compounded ketamine, Spravato is administered only in certified clinical settings with a mandatory two-hour monitoring period after each dose.
Neither ketamine nor Spravato is an opioid, and neither is used in the way opioids are prescribed for pain management.
Looking for Spravato or ketamine treatment near you?
Pacific Mind Health offers Spravato (esketamine) and ketamine therapy for treatment-resistant depression, major depressive disorder, and more.
Located in Southern California and serving patients across the state, Pacific Mind Health was founded by Joshua Flatow, MD, a board-certified psychiatrist and published research author.
Ready to take the next step? Schedule a free consultation today to see if Spravato or ketamine is right for you.
Frequently asked questions
Is ketamine an opioid?
No, ketamine is not an opioid. It is a dissociative anesthetic that works primarily by blocking NMDA receptors in the glutamate system, which is a different neurological pathway than the one opioids act on. Ketamine does not bind to opioid receptors the way opioid drugs do. It does not cause the respiratory depression associated with opioid overdose and is classified by the DEA as a Schedule III controlled substance, a separate category from Schedule II opioids.
Why do some people think ketamine is an opioid?
The confusion likely comes from several overlapping factors. Both ketamine and opioids can relieve pain, both have histories of misuse, and both affect mood. A 2024 Stanford study also found that the opioid system may play a partial role in how ketamine’s antidepressant effects work in some people, which generated media coverage. However, this does not make ketamine an opioid. The drugs remain fundamentally different in their classification, mechanism, and risk profile.
Is ketamine safe for people in opioid recovery?
This is an important clinical question that should be discussed with a treating psychiatrist. Ketamine is not an opioid, so it does not work on the same receptors. However, people in recovery from any substance use disorder should always disclose their full history before starting any new treatment, including ketamine. A qualified psychiatrist can evaluate individual risk factors and determine whether ketamine therapy is appropriate.
What is the difference between ketamine and Spravato?
Spravato (esketamine) is a nasal spray form of esketamine, a close chemical relative of ketamine. It is FDA-approved for treatment-resistant depression and major depressive disorder with suicidal ideation. Compounded ketamine is used off-label for a broader range of conditions. Both target the glutamate system, neither is an opioid, and both are administered under clinical supervision. The key practical differences involve FDA approval status, insurance coverage, and the specific conditions they are used to treat.
Can ketamine be used for pain without being an opioid?
Yes. Ketamine has been used in medical settings for pain management as an alternative or complement to opioids, particularly for patients who have not responded well to opioid-based pain treatment or for whom opioid use carries heightened risks. Its pain-relieving properties come from its NMDA receptor blockade, not from opioid receptor activity. Research into ketamine for chronic pain is ongoing.
