Yes, ketamine is used for general anesthesia and has been since the 1960s. It remains one of the most versatile anesthetic agents available, listed on the World Health Organization’s Model List of Essential Medicines since 1984 for induction and maintenance of anesthesia. What makes ketamine unusual compared to other anesthetics is that it produces a unique state called “dissociative anesthesia,” where you lose consciousness and feel no pain but continue breathing on your own.
How Ketamine Works Differently
Most general anesthetics suppress brain activity broadly, which is why they also suppress breathing and relax muscles. Ketamine takes a different path. It blocks a specific type of receptor in the brain (called the NMDA receptor) by physically plugging the channel that ions flow through. The drug molecule enters the channel when it opens, blocks the flow, and can remain lodged there even after the channel closes. This “trapping” mechanism disconnects the brain’s sensory processing from conscious awareness, producing anesthesia without shutting down the brainstem centers that control breathing.
The result is a patient who is unconscious, pain-free, and amnesic but still maintaining their own airway and respiratory drive. That combination is rare among anesthetics and is the main reason ketamine holds a distinct role in surgical practice.
Where Ketamine Is Preferred Over Other Anesthetics
Ketamine isn’t the default choice for routine surgeries in well-equipped hospitals, where agents like propofol and inhaled anesthetics dominate. But there are specific situations where ketamine becomes the preferred or even the only safe option.
Trauma and emergency settings. Ketamine mildly increases heart rate, blood pressure, and cardiac output by stimulating the sympathetic nervous system. For a patient who has lost blood or is in shock, this is a significant advantage. Other anesthetics tend to drop blood pressure further, which can be dangerous. Ketamine is widely used for prehospital anesthesia, disaster medicine, and emergency surgeries where hemodynamic stability matters most. A study of emergency laparotomies found that combining ketamine with propofol in a 1:1 ratio reduced the incidence of dangerous blood pressure drops to 12%, compared to 35% when less ketamine was used.
Pediatric procedures. Children present unique challenges: they’re often uncooperative, have small veins that are hard to access, and their airways are more prone to spasm. Ketamine can be given intramuscularly (a shot in the muscle), which avoids the need for an IV line before induction. It also has a mild bronchodilating effect, making it useful in children at risk of airway spasm. It has been used successfully in pediatric cardiac surgery, including correction of complex heart defects like Tetralogy of Fallot, with excellent hemodynamic stability.
Patients at risk of malignant hyperthermia. Children and adults with certain neuromuscular disorders can have a life-threatening reaction to common inhaled anesthetics and muscle relaxants. Ketamine allows clinicians to avoid those triggers entirely while still providing full general anesthesia.
Difficult airway situations. When a patient’s airway anatomy makes intubation risky, ketamine allows anesthesia while the patient keeps breathing spontaneously. This gives the clinical team more time and a safer margin to secure the airway.
Resource-limited settings. Ketamine is inexpensive, stable at room temperature, and doesn’t require sophisticated monitoring equipment or mechanical ventilation. It has long been the anesthetic of choice in remote areas, field hospitals, and low-resource surgical programs worldwide.
Dosing and Administration
The FDA-approved intravenous induction dose ranges from 1 to 4.5 mg/kg, with 2 mg/kg as the average. At these doses, a single IV injection produces unconsciousness within about 30 seconds. When given as an intramuscular injection, onset takes several minutes longer, and higher doses are typically needed. Ketamine can also be used for maintenance of anesthesia through repeated doses or a continuous infusion, not just for induction.
Breathing and Airway Preservation
One of ketamine’s most clinically valuable properties is what it doesn’t do: it doesn’t suppress breathing. Research comparing ketamine to propofol found that ketamine actually stimulates respiration, increasing respiratory rate, airflow, and the amount of time spent actively inhaling. Patients under ketamine anesthesia had lower carbon dioxide levels than during normal wakefulness, meaning they were breathing more effectively, not less.
The mechanism behind this involves a muscle at the base of the tongue called the genioglossus, which keeps the upper airway open. Most anesthetics relax this muscle, causing the tongue to fall back and obstruct breathing. Ketamine does the opposite. Studies measured genioglossus activity at 1.5 to 5 times higher than during natural sleep or propofol anesthesia. This is why ketamine is sometimes described as the only anesthetic that “uncouples” unconsciousness from airway collapse. In critically ill children, airway obstruction rates are lower with ketamine compared to propofol.
Cardiovascular Effects
Ketamine stimulates the release of stress hormones that increase heart rate and blood pressure. These effects are generally mild to moderate and temporary. For most patients, this is either neutral or beneficial. For patients in hemorrhagic shock or with low blood pressure from sepsis, it can be lifesaving.
The cardiovascular stimulation does carry risk in certain populations. In patients with uncontrolled high blood pressure or coronary artery disease, the increase in heart rate and blood pressure could theoretically worsen cardiac strain. One study of procedural sedation in adults defined a clinically significant change as a 20% or greater shift from baseline values, and a small number of patients showed electrocardiogram changes suggestive of cardiac stress alongside those blood pressure and heart rate increases.
Intracranial Pressure: An Outdated Concern
For decades, ketamine was avoided in patients with head injuries because of a belief that it raised pressure inside the skull. This concern has been largely overturned. Current evidence shows that ketamine does not produce sustained increases in intracranial pressure and may, in some cases, actually reduce it. An emerging consensus now supports ketamine as safe for brain-injured patients when used appropriately, though formal clinical guidelines on the topic are still evolving from individual studies and meta-analyses.
Recovery and Side Effects
Waking up from ketamine feels different from waking up after other anesthetics. The transition back to full consciousness can include vivid dreams, hallucinations, confusion, or a feeling of floating. This is known as emergence phenomena, and it occurs in roughly 6% to 12% of patients. Some people experience brief involuntary muscle movements during emergence that can look alarming but are not seizures and don’t require additional anesthesia.
When emergence reactions are more intense, with agitation, disorientation, or distressing hallucinations, clinicians can treat them with a small dose of a sedative. The risk of these reactions can be reduced by using lower ketamine doses, administering a sedative alongside it, and keeping the recovery environment quiet with minimal stimulation.
Full neurological recovery must be confirmed before discharge. After ketamine anesthesia, you should not drive, operate heavy machinery, or perform any potentially dangerous activities for at least 24 hours. A responsible adult needs to be present for your discharge and supervision afterward.
Ketamine Combined With Other Agents
In modern practice, ketamine is frequently combined with other anesthetics rather than used alone. The most well-known combination is “ketofol,” a mixture of ketamine and propofol. The idea is simple: propofol causes deep unconsciousness but drops blood pressure, while ketamine raises it. Mixed together, the two drugs counterbalance each other’s side effects, providing stable unconsciousness with less hemodynamic disruption than either drug alone. Mixing ratios in clinical use range from 1:1 to 1:10 (propofol to ketamine), with a 1:1 ratio showing the best blood pressure stability in emergency surgery settings.
This combination approach reflects how ketamine fits into general anesthesia today. Rather than being the sole anesthetic for major surgery, it often serves as one component of a balanced anesthetic plan, contributing its unique strengths in pain control, airway preservation, and cardiovascular support while other agents handle the rest.