At what point is a patient considered for ketamine treatment?

When to Consider Ketamine Treatment for Patients

Ketamine treatment should be initiated for patients with treatment-resistant depression who have failed at least two adequate trials of antidepressants and continue to experience severe depressive symptoms with significant functional impairment. 1

Primary Indications for Ketamine Treatment

Treatment-Resistant Depression (TRD)

• Patients who have failed multiple adequate antidepressant therapies (at least two trials)
• Patients with severe depressive symptoms causing significant functional impairment
• Patients who need rapid intervention for depressive symptoms 1

Acute Suicidal Ideation

• Patients with active suicidal thoughts requiring rapid intervention
• Evidence shows significant reduction in suicidal ideation within 40 minutes of administration
• Particularly effective in patients with high baseline suicidal ideation (SSI score >3) 2

Pain Management Scenarios

• Patients with refractory chronic pain, especially with neuropathic components
• Patients with inadequate pain control despite high-dose opioids
• Patients with opioid tolerance or hyperalgesia 2, 3

Patient Selection Algorithm

1. For Depression Treatment:

   • Confirm treatment resistance (≥2 failed adequate antidepressant trials)
   • Assess severity of depression and functional impairment
   • Rule out contraindications (uncontrolled cardiovascular disease, active psychosis, severe liver dysfunction) 1

2. For Acute Pain Management:

   • Consider for major surgeries (abdominal, pelvic, spinal) when regional analgesia isn't possible
   • Particularly beneficial for patients with high risk of acute pain or chronic postoperative pain
   • Indicated for patients with vulnerability to pain, especially those taking long-term opioids 2

3. For Trauma Patients:

   • Consider for elderly trauma patients, particularly those with rib fractures
   • Can be used as alternative to opioids to reduce side effects
   • Effective as part of multimodal analgesia approach 2

Dosing Considerations

• For Depression: 0.5 mg/kg IV over 40 minutes (range 0.1-0.75 mg/kg) 1
• For Perioperative Pain:
  • Intraoperative: Maximum dose of 0.5 mg/kg/h after anesthesia induction
  • Continuous infusion: 0.125-0.25 mg/kg/h (stop 30 min before end of surgery) 2
• For Acute Pain: 0.5 mg/kg IV bolus followed by 1-2 μg/kg/min infusion 1

Important Caveats and Monitoring Requirements

• Must be administered in a healthcare setting under direct supervision
• Monitoring required for at least 2 hours after administration
• Blood pressure monitoring essential due to potential transient increases
• Assessment for psychotomimetic side effects (dysphoria, hallucinations) 1
• Risk of abuse must be considered, especially with domiciliary treatment 4

Duration and Frequency of Treatment

• Single infusion effects may last 24 hours to several days
• For sustained benefit, repeated infusions (2-3 times per week) may be necessary
• Maintenance treatment may be individualized based on when previous session's effects wear off 4
• Approximately 70% of responders may relapse by 4 weeks following final infusion 2

Efficacy Expectations

• Approximately 70% of patients may experience significant benefit from ketamine therapy 1
• Effects can be seen as early as 40 minutes after administration
• Long-term efficacy data is limited, with some studies showing diminishing returns after 6 months 1
• For pain management, ketamine can reduce morphine consumption by approximately 15 mg in 24 hours 2

Ketamine represents an important treatment option for specific patient populations who have not responded to conventional therapies. The decision to initiate ketamine should be based on careful assessment of the risk-benefit profile for each individual patient, with particular attention to monitoring requirements and potential side effects.