From the Guidelines
Ketamine infusion for acute pain should be administered at a dose of 0.5-1 mg/kg/h, with no intensive monitoring required, as recommended for severe pain management. This dose range is supported by the most recent and highest quality study available, which suggests that subanesthetic doses of ketamine have evidence of efficacy in acute pain management 1. The use of ketamine in acute pain management is also supported by another study, which recommends using low-dose ketamine as an adjunct to opioid therapy to reduce opioid consumption in postsurgical adults admitted to the ICU 1.
Key Considerations
- Ketamine works by blocking NMDA receptors, which helps prevent central sensitization and reduces opioid tolerance.
- Patients should be monitored for potential side effects, including hallucinations, vivid dreams, nystagmus, and increased blood pressure, although these side effects are dose-dependent and less common at the low doses used for analgesia.
- The infusion should be administered in a monitored setting with appropriate equipment for vital sign monitoring and staff trained to recognize adverse effects.
- Ketamine is particularly useful for patients with opioid-resistant pain, those with high opioid requirements, or in situations where opioid-sparing techniques are preferred.
Administration Guidelines
- The infusion is usually initiated after a loading dose of 0.1-0.3 mg/kg and continued for 24-72 hours depending on pain severity and patient response.
- Gradual tapering rather than abrupt discontinuation is recommended when stopping the infusion to prevent rebound pain.
- Ketamine should not be used in uncontrolled cardiovascular disease, pregnancy, active psychosis, severe liver dysfunction, high intracranial, and ocular pressure 1.
From the Research
Ketamine Infusion for Acute Pain
- The optimal dose of intravenous ketamine for acute pain management has yet to be identified, but studies suggest that sub-dissociative doses (0.1-0.6 mg/kg) are safe and effective 2.
- A study found that low-dose ketamine (<0.3 mg/kg) is an effective and safe pain management strategy for acute pain in the emergency department, with no significant difference in analgesic efficacy and safety compared to high-dose sub-dissociative ketamine (≥0.3 mg/kg) 2.
- Another study compared the efficacy of bolus low-dose ketamine versus bolus plus infusion low-dose ketamine for pain management in the emergency department, and found that both administration protocols resulted in significant pain control with no statistically significant difference in analgesic efficacy and side effects 3.
- A prospective study administered a low-dose ketamine bolus followed by continuous infusion and found that it provided clinically significant and sustained pain relief, with mostly mild side effects and no severe adverse events 4.
- Ketamine has been suggested as an alternative to opioids for acute pain management, with some studies showing that it can be effective for immediate pain relief, but with high heterogeneity in the included studies 5.
Dosage and Administration
- A study used a dose of 0.3 mg/kg of ketamine over 1 minute, followed by an infusion of saline 0.9% over the next 30 minutes, while another group received 0.15 mg/kg of ketamine over 1 minute, followed by an infusion of 0.15 mg/kg over the next 30 minutes 3.
- Another study administered 15 mg intravenous ketamine followed immediately by continuous ketamine infusion at 20 mg/h for 1 hour 4.
- The dosage and administration of ketamine for acute pain management may vary depending on the specific clinical context and patient population, and further studies are needed to determine the optimal dosing regimen 2, 3, 4.