What is the effective dose of ketamine for pain management?

From the Guidelines

The effective dose of ketamine for pain management is 0.5 mg/kg IVP x 1 followed by 1-2 μg/kg/min infusion.

Key Points

• The use of low-dose ketamine as an adjunct to opioid therapy is suggested for postsurgical adults admitted to the ICU to reduce opioid consumption 1.
• The recommended dose is 0.5 mg/kg IVP x 1 followed by 1-2 μg/kg/min infusion 1 or 1–2 μg/kg/hr 1.
• Ketamine has been shown to reduce opioid requirements, but its effect on patient-reported pain intensity is unclear 1.
• The frequency of side effects, such as nausea, delirium, and hallucinations, was similar between the ketamine and control groups 1.
• The evidence for using ketamine in cancer pain management is limited, but it may have modest analgesic potential 1.
• Subanaesthetic doses of ketamine may be beneficial for intractable pain, including neuropathic pain 1.

From the FDA Drug Label

The ketamine hydrochloride injection dosage must be individualized and titrated to the desired clinical effect. If a longer duration of effect is desired, additional increments can be administered intravenously or intramuscularly to maintain anesthesia. However, a higher total dose will result in a longer time to complete recovery Induction of Anesthesia Intravenous Route: The initial dose of ketamine hydrochloride injection administered intravenously may range from 1 mg/kg to 4.5 mg/kg. The average amount required to produce 5 to 10 minutes of surgical anesthesia within 30 seconds following injection is 2 mg/kg. Administer ketamine hydrochloride injection slowly (i.e., over a period of 60 seconds). Rapid administration may result in respiratory depression and enhanced vasopressor response. The induction dose may be administered as an intravenous infusion at a rate of 0.5 mg/kg/min. Intramuscular Route: The initial dose of ketamine hydrochloride injection administered intramuscularly may range from 6.5 to 13 mg/kg. 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 effective dose of ketamine for pain management is not explicitly stated in the label, as the label primarily discusses the use of ketamine for induction and maintenance of anesthesia. However, based on the information provided for induction of anesthesia, the initial dose of ketamine hydrochloride injection administered intravenously may range from 1 mg/kg to 4.5 mg/kg, with an average dose of 2 mg/kg required to produce 5 to 10 minutes of surgical anesthesia. For intramuscular administration, the initial dose may range from 6.5 to 13 mg/kg, with a dose of 9 to 13 mg/kg usually producing surgical anesthesia within 3 to 4 minutes. The maintenance dose is adjusted according to the patient's anesthetic needs, with repeat increments of one-half to the full induction dose as needed. Ketamine hydrochloride injection can be given by slow microdrip infusion technique at a dose of 0.1 to 0.5 mg/minute to maintain general anesthesia in adult patients induced with ketamine hydrochloride injection 2.

From the Research

Effective Dose of Ketamine for Pain Management

The effective dose of ketamine for pain management varies depending on the specific condition being treated and the route of administration.

• For acute pain in the emergency setting, low-dose ketamine (less than 0.5 milligrams per kilogram) may have higher or equivalent efficacy and safety compared to opioids 3.
• For chronic pain management, a recommended starting dosage is 0.5 mg/kg racemic ketamine or 0.25 mg/kg S-ketamine as a single oral dose, which can be increased as needed 4.
• IV ketamine infusions have been shown to provide significant short-term analgesic benefit in patients with refractory chronic pain, with some evidence of a dose-response relationship 5.
• Subanesthetic doses of ketamine have been found to be effective in cancer-associated neuropathic pain, ischemic pain, and regional pain syndromes, and can be administered orally, intravenously, subcutaneously, or topically 6.

Dosage Considerations

• The dosage of ketamine should be individualized based on the patient's response and tolerance to the medication.
• The use of ketamine in chronic pain management is generally considered a "third line" option, to be used when standard analgesic options have failed 7.
• The evidence for efficacy of ketamine for treatment of chronic pain is moderate to weak, and further controlled studies are needed to determine the optimal treatment protocol 7, 5.

Administration Routes

• Ketamine can be administered via various routes, including oral, intravenous, subcutaneous, and topical 4, 6.
• The choice of administration route may depend on the specific condition being treated, as well as patient preferences and tolerability.

Safety and Efficacy

• The safety and efficacy of ketamine for pain management have been evaluated in several studies, with varying results 3, 4, 7, 5.
• Common side effects of ketamine include gastrointestinal, neurological, psychological, and cardiopulmonary effects, which should be carefully monitored and managed 3.