From the FDA Drug Label
A dose of 9 to 13 mg/kg usually produces surgical anesthesia within 3 to 4 minutes following injection, with the anesthetic effect usually lasting 12 to 25 minutes. The onset of action of intramuscular (IM) ketamine is 3 to 4 minutes [@\1@].
From the Research
Onset of Action of Intramuscular (IM) Ketamine
- The onset of action of IM ketamine has been reported in several studies:
- A study published in 2015 found that the onset of action of IM ketamine was 8.6 ± 3.1 minutes 1.
- A study published in 2018 found that the mean time between injection and onset of drug effect in the IM group was 5.71 min 2.
- Another study published in 1982 found that absorption after IM injection was rapid, but did not provide a specific time for onset of action 3.
- These studies suggest that the onset of action of IM ketamine is relatively rapid, but may vary depending on the specific study and population.
Comparison to Other Routes of Administration
- The onset of action of IM ketamine has been compared to other routes of administration, such as intravenous (IV) and oral:
- A study published in 2015 found that the onset of action of IV ketamine was 1.7 ± 1.1 minutes, which was significantly faster than IM ketamine 1.
- A study published in 1981 found that oral ketamine had a slower onset of action compared to IM ketamine, with pain thresholds increased at 30 min after oral administration 4.
- These studies suggest that the onset of action of IM ketamine is slower than IV ketamine, but may be faster than oral ketamine.
Factors Affecting Onset of Action
- Several factors may affect the onset of action of IM ketamine, including:
- Dose: The dose of ketamine may affect the onset of action, with higher doses potentially leading to faster onset 1.
- Population: The onset of action of IM ketamine may vary depending on the population being studied, such as children or adults 1, 2.
- Method of administration: The method of administration, such as the use of a specific injection technique, may also affect the onset of action of IM ketamine 2.