How Long Does Ketamine Last? Duration of Effects

What you will learn

• Ketamine is a dissociative anesthetic with varied effects whose duration depends on administration method, dosage, body weight, and individual metabolism.
• The onset of effects ranges from seconds (IV) to 90 minutes (oral), with therapeutic uses in depression, PTSD, and pain management alongside risks when used recreationally.
• Multiple factors influence duration, including dosage, age, liver/kidney function, concurrent medications, tolerance, hydration, and individual brain chemistry.
• Safety requires medical supervision, the complete disclosure of medical history, following pre-procedure instructions, arranging transportation after treatment, and awareness of addiction risks, including psychological dependence and physical harm to organs.

Ketamine is a powerful medication that produces a range of effects, from anesthesia to psychedelic-like experiences, depending on dosage. Its duration varies significantly based on several factors, including administration method, dosage, body weight, and individual metabolism. Knowing how long ketamine stays active in your system is important if you’re receiving it as a prescribed treatment, participating in ketamine-assisted therapy, or managing potential side effects.

What is Ketamine?

Ketamine is a dissociative anesthetic drug first developed in the 1960s for medical use.[1] It works by blocking NMDA receptors in the brain, which alters perception and produces feelings of detachment from reality. Originally used as a battlefield anesthetic during the Vietnam War, ketamine remains an important medicine in operating rooms and emergency settings because it provides pain relief and sedation while maintaining respiratory function.

Ketamine can be used for conditions like treatment-resistant depression, post-traumatic stress disorder (PTSD), and chronic pain.[2] When administered in controlled medical environments, ketamine can produce rapid antidepressant effects.

Outside medical settings, ketamine is sometimes misused as a recreational substance due to its dissociative and hallucinogenic properties. These effects might include feelings of floating, visual distortions, and a sense of detachment from one’s body. Recreational use carries significant risk, including addiction, cognitive impairment, and bladder damage with long-term exposure.[3] The drug’s impact varies greatly depending on dosage, with higher amounts producing more intense dissociative states.

How Long Does Ketamine Take to Work – and How Long Do Effects Last?

Ketamine begins producing effects at different rates depending on how it’s administered.[4] When given intravenously (IV), ketamine works almost immediately, often within seconds to minutes. This rapid onset makes IV ketamine particularly valuable in emergency medical situations and controlled therapeutic settings where immediate relief is needed. For other administration methods, the timeline varies. Intramuscular (IM) injections typically take five to ten minutes before effects become noticeable. Intranasal ketamine (like the FDA-approved Spravato) generally begins working within ten to fifteen minutes. Oral ketamine takes the longest, with effects starting thirty to ninety minutes after ingestion due to the digestive process.

Common Ketamine duration of effects and their intensity depend on several factors:[5]

• Dosage determines how strong and how long the effects last. Higher doses generally produce more intense and longer-lasting effects.
• The method of administration affects both onset and duration. IV ketamine effects are intense but shorter-lasting compared to oral doses.
• Individual metabolism significantly affects how quickly your body processes the drug.
• Body weight influences how concentrated the drug becomes in your system.
• Prior exposure to ketamine can create tolerance, potentially reducing effects.
• Drug interactions and medication usage may extend or diminish ketamine’s effects.
• Liver function affects how efficiently your body metabolizes and clears ketamine.

The duration of ketamine’s effects can vary from person to person. While some people may experience effects for just an hour, others might feel the impact for several hours or longer. This variability stems from numerous factors that influence how ketamine is processed and experienced in the body.

Individual biology helps to determine how long ketamine remains active. Your unique genetic makeup affects enzyme production, particularly the cytochrome P450 enzymes in your liver that metabolize ketamine.[6] Some naturally process ketamine more quickly or slowly based on these genetic differences. Additionally, your kidney function affects how efficiently ketamine and its metabolites are filtered and eliminated from your body.

Safe Guidelines For Ketamine

Ketamine should only be used under proper medical supervision in approved clinical settings. This powerful medication requires careful administration by trained professionals who can monitor vital signs, manage potential side effects, and provide appropriate psychological support.

Never attempt to self-administer ketamine or obtain it from unofficial sources, as unregulated products may contain dangerous contaminants, and precise dosing is critical for safety. Before receiving ketamine treatment, provide your doctor with a complete medical history, including all current medications, supplements, medical conditions, and substance use.

Certain conditions like uncontrolled high blood pressure, heart disease, liver problems, or a history of psychosis may increase risks. Some medications may interact with ketamine, potentially causing dangerous side effects or reducing therapeutic benefits. Your healthcare provider needs this information to determine if ketamine is appropriate for you and to establish the safest treatment protocol.

During ketamine treatment, follow all pre-procedure instructions, such as fasting requirements or medication adjustments. Arrange for someone else to drive you home afterward, as ketamine impairs coordination, judgment, and reaction times for several hours. Avoid alcohol, recreational drugs, and operating machinery for at least 24 hours following treatment. Report any concerning side effects to your healthcare provider immediately, especially symptoms like severe confusion, difficulty breathing, chest pain, or signs of urinary tract problems that require prompt medical attention.

Ketamine Abuse and Addiction

When people use ketamine without medical supervision, they can develop patterns of misuse that may lead to addiction. The mind-altering effects can become psychologically addictive, causing cravings and continued use despite negative consequences. Some people start needing larger doses as their bodies develop tolerance, and they might experience withdrawal symptoms when trying to stop. This cycle of dependence can be especially powerful for people trying to escape emotional pain or difficult life situations.

Long-term ketamine use can also impair memory, concentration, and thinking skills.[7] The dissociative effects of ketamine make accidents more likely and can worsen existing mental health problems. Despite these risks, people struggling with ketamine addiction often find it difficult to stop without professional help and support.

Amanda is a prolific medical content writer specializing in eating disorders and addiction treatment. She graduated Magna Cum Laude from Purdue University with a B.S. in Social Work. Read more