What are the guidelines for taking oral (PO) ketamine?

Guidelines for Taking Oral (PO) Ketamine

Oral ketamine should be administered at doses of 1-2 mg/kg every 1-3 days for depression treatment, with careful monitoring for psychotomimetic effects and consideration of individual patient factors. 1, 2, 3

Dosing Guidelines

• For depression treatment, oral ketamine doses typically range from 0.25 to 7.0 mg/kg, with most studies using 1-2 mg/kg every 1-3 days 3
• Fixed doses between 50-300 mg per occasion have been used in clinical studies for depression 1
• Due to poor oral bioavailability (approximately 20-25%), oral doses of 2.0-2.5 mg/kg may be needed to achieve equivalence to intravenous ketamine 2
• For perioperative pain management, subanesthetic doses are recommended with maximum infusion rates of 0.5 mg/kg/h after anesthesia induction, followed by continuous infusion at 0.125-0.25 mg/kg/h 4
• For acute pain management, subanesthetic doses include boluses <0.35 mg/kg and infusions at 0.5-1 mg/kg/h 4

Administration Considerations

• Oral ketamine can be administered through weight-based dosing or as fixed doses 2
• Dosing strategies may be standardized or individualized through a dose discovery process 2
• When used for depression, antidepressant effects may take 2-6 weeks to become significant, unlike the rapid effects seen with IV administration 3
• For chronic pain management, a quarter-century of experience supports oral ketamine use in both children and adults 1

Monitoring and Safety

• Regular assessment of sedation levels and respiratory status is essential when using ketamine 4
• When ketamine is administered for moderate procedural sedation, care consistent with that required for general anesthesia should be provided 5
• Practitioners administering ketamine must be able to identify and rescue patients from unintended deep sedation or general anesthesia 5
• For patients receiving ketamine, maintain vascular access throughout the procedure until the patient is no longer at risk for cardiorespiratory depression 5

Contraindications

• Ketamine should not be used in patients with uncontrolled cardiovascular disease, pregnancy, active psychosis, severe liver dysfunction, or high intracranial/ocular pressure 4
• Caution should be exercised in patients with a history of substance abuse due to ketamine's potential for misuse 2, 6

Adverse Effects

• Psychotomimetic effects (hallucinations, dissociation) are common but typically mild at subanesthetic doses 1, 7
• Continuation of ketamine treatment in the postoperative period increases risk of hallucinations without significantly enhancing analgesic effect 4
• Most studies report good tolerability with oral ketamine, with dropout rates similar between ketamine and control groups in randomized controlled trials 1

Clinical Applications

• Oral ketamine has shown efficacy in treating severe depression, depression with suicidal ideation, and treatment-resistant depression 1
• It can be used as an augmentation agent to improve outcomes in patients receiving conventional antidepressants 1
• For perioperative pain, the American Society of Anesthesiologists recommends ketamine in two scenarios: surgery with high risk of acute pain or chronic postoperative pain, and patients with vulnerability to pain, particularly those taking long-term opioids 4
• Strong evidence supports the use of intravenous ketamine in the perioperative period to reduce opioid use in the first 24 hours after hip and knee arthroplasty 5

Practical Implementation

• For depression treatment, frequency can be individualized with ketamine dosed shortly before the effect of the previous session is expected to wear off 6
• When administering oral ketamine, allow sufficient time for absorption and peak effect before considering supplementation 5
• If patients develop hypoxemia or significant hypoventilation during sedation, they should be encouraged to breathe deeply, administered supplemental oxygen, and provided positive pressure ventilation if needed 5