From the Guidelines
The duration of action of ketamine is approximately 10-30 minutes after intravenous administration, with a rapid onset of action of 1 minute. For intravenous (IV) administration:
- Onset: 1 minute
- Peak effect: 5-10 minutes
- Duration: 10-30 minutes This information is based on the most recent and highest quality study available, which reported that ketamine has a rapid onset of action and short duration of effect 1. The study published in 2012 in the journal Gastroenterology, states that ketamine is highly lipid soluble with a rapid onset of action (1 minute) and short duration of action (15-30 minutes) 1. Another study published in 2007, also in the journal Gastroenterology, reported that after intravenous administration, ketamine has a rapid onset of action (1 min) and short duration of effect (10–15 min) 1. However, the 2012 study is more recent and provides a slightly longer duration of action, which is consistent with the pharmacokinetics of ketamine. It's worth noting that the duration of action may vary depending on the individual patient and the specific context in which ketamine is being used. In general, ketamine's rapid onset and short duration of action make it a useful agent for short procedures or as an initial anesthetic agent, but its psychoactive effects may persist longer than its analgesic effects, so patients should be monitored for several hours after administration. The dosage of ketamine varies based on the intended use and should be determined by a healthcare professional, with typical dosages ranging from 0.5-2 mg/kg for IV use 1.
From the FDA Drug Label
The onset of action of ketamine is rapid; an intravenous dose of 2 mg/kg (1 mg/lb) of body weight usually produces surgical anesthesia within 30 seconds after injection, with the anesthetic effect usually lasting five to ten minutes If a longer effect is desired, additional increments can be administered intravenously or intramuscularly to maintain anesthesia without producing significant cumulative effects. Intramuscular doses, in a range of 9 to13 mg/kg (4 to 6 mg/lb) usually produce surgical anesthesia within 3 to 4 minutes following injection, with the anesthetic effect usually lasting 12 to 25 minutes
The duration of action of ketamine is:
- 5 to 10 minutes for an intravenous dose
- 12 to 25 minutes for an intramuscular dose 2
From the Research
Duration of Action of Ketamine
The duration of action of ketamine can vary depending on the dose, route of administration, and individual response.
- According to 3, the benefits of ketamine as an antidepressant are observed within hours of administration, peak after about a day, and are lost 3-12 days later.
- The study 3 also mentions that benefits can be maintained for weeks to months by the continuation of ketamine sessions at 2- to 4-day intervals.
- Additionally, 4 states that ketamine has a relatively short half-life of 2-3 hours.
Factors Influencing Duration of Action
Several factors can influence the duration of action of ketamine, including:
- Dose: Higher doses may result in longer durations of action, but also increase the risk of side effects 5, 3.
- Route of administration: The route of administration can affect the onset and duration of action, with intravenous administration resulting in a faster onset but shorter duration compared to other routes 5, 4.
- Individual response: Individual responses to ketamine can vary significantly, with some patients experiencing longer or shorter durations of action than others 3.