Ketamine Dosing Calculator

The Ketamine Dosing Calculator provides weight-based dosing guidance for ketamine across its diverse clinical applications. Ketamine is a dissociative anesthetic agent that has experienced a remarkable renaissance in modern medicine, with expanding roles in analgesia, procedural sedation, emergency airway management, and treatment-resistant depression. Understanding the appropriate dosing for each indication and route of administration is essential for safe and effective use.

Originally developed in 1962 and approved by the FDA in 1970, ketamine acts primarily as an NMDA (N-methyl-D-aspartate) receptor antagonist, with additional effects at opioid, monoaminergic, and cholinergic receptors. Its unique pharmacological profile produces dose-dependent effects ranging from analgesia at sub-dissociative doses to complete dissociative anesthesia at higher doses, while maintaining protective airway reflexes and hemodynamic stability in most patients.

For low-dose analgesia (sub-dissociative ketamine), IV doses of 0.1-0.3 mg/kg provide potent analgesia without dissociation. This application has gained significant traction in emergency departments as an opioid-sparing analgesic strategy. Studies demonstrate equivalent pain relief to opioids for acute pain, with the added benefit of bronchodilation and hemodynamic preservation. Low-dose ketamine infusions (0.1-0.3 mg/kg/hour) are increasingly used for perioperative pain management.

Procedural sedation requires higher doses of 1.0-2.0 mg/kg IV or 4-5 mg/kg IM to achieve dissociative anesthesia. This provides excellent conditions for painful procedures while maintaining airway reflexes and spontaneous ventilation. The dissociative state typically lasts 10-20 minutes with IV administration and 15-30 minutes with IM, with full recovery in 1-2 hours. Emergence reactions occur in approximately 10-20% of adults but can be mitigated with concurrent benzodiazepines.

For rapid sequence intubation (RSI), ketamine at 1.5-2.0 mg/kg IV is the induction agent of choice in hemodynamically unstable patients, those with bronchospasm, and many trauma scenarios. Unlike other induction agents, ketamine maintains sympathetic tone, preserving blood pressure and heart rate. Its bronchodilatory properties make it particularly valuable in patients with reactive airway disease.

The intranasal (IN) route has emerged as a practical alternative for patients without IV access, particularly in pediatric and prehospital settings. Bioavailability is approximately 25-50% compared to IV, requiring higher doses (approximately 1.5x the IV dose). For treatment-resistant depression, low-dose IV ketamine (0.5 mg/kg over 40 minutes) or intranasal esketamine (Spravato) has shown rapid antidepressant effects within hours, representing a breakthrough in psychiatry.

Key safety considerations include: monitoring for laryngospasm (rare but serious), managing emergence reactions (disorientation, vivid dreams), avoiding use in patients with conditions where increased intracranial or intraocular pressure is concerning, and ensuring appropriate monitoring equipment and personnel are available.

This calculator provides indication-specific and route-adjusted ketamine dosing to support safe clinical use across the spectrum of ketamine applications.