Ketamine Toxicity Symptoms
Ketamine toxicity primarily manifests as cardiovascular effects (tachycardia, hypertension), neuropsychiatric symptoms (emergence reactions, hallucinations), and respiratory issues (laryngospasm), with chronic use leading to urological and hepatobiliary complications. 1, 2, 3
Acute Toxicity Symptoms
Cardiovascular Effects
- Tachycardia - most common physical examination finding 4
- Hypertension - dose-dependent increase in blood pressure 1
- Arrhythmias - less common but reported 2
- Rarely: hypotension and bradycardia 2
Neuropsychiatric Effects
- Emergence reactions (10-30% of adults) 1
- Floating sensations
- Vivid dreams
- Hallucinations
- Delirium
- Anxiety and agitation 4
- Disorientation and irrational behavior 3
- Nystagmus and diplopia 2
- Dizziness 3
- Ataxia (reported in 7% of cases) 5
Respiratory Effects
- Laryngospasm (0.9-1.4% in general settings, higher in children <6 years at 13.9%) 5
- Respiratory depression (rare with ketamine alone, increased when combined with other sedatives) 5, 2
- Hypoxemia (SpO₂ <90%) in approximately 1.6% of cases 5
- Increased secretions 5
Gastrointestinal Effects
Chronic Toxicity Symptoms
Urological Effects
- Ketamine-induced cystitis 3, 6
- Urinary frequency
- Urgency
- Dysuria
- Hematuria
- Suprapubic pain
- Renal failure (rare) 6
Hepatobiliary Effects
Neuropsychological Effects
- Cognitive impairment 3, 6
- Impaired verbal information processing
- Memory deficits
- Attention problems
- Psychological addiction 6
- Withdrawal syndrome with psychotic features after long-term use 2
Risk Factors for Severe Toxicity
- Combination with other sedatives or opioids (increases risk of respiratory depression) 5
- Young age (higher risk of recovery agitation) 5
- Higher ASA status (American Society of Anesthesiologists physical status) 5
- Impaired skin barrier function (can lead to increased absorption with topical formulations) 7
- Procedures involving the gastrointestinal tract (higher risk of laryngospasm) 5
Diagnostic Considerations
- Diagnosis typically based on history, clinical features, and presentation 3
- Toxicology screening may be necessary for confirmation 1
- For date-rape cases, testing should be performed quickly as ketamine is detectable in urine for only 24-72 hours 1
Management Pearls
- Benzodiazepines are recommended as initial treatment for agitation, neuromuscular activity, and blood pressure control 3
- Most symptoms are self-limiting and resolve within hours 4
- Supportive care is the mainstay of treatment 3
- For chronic effects, abstinence is key to reversibility 3
- Midazolam may be used in combination with ketamine but does not decrease recovery agitation and increases risk of respiratory depression 5
Remember that ketamine toxicity symptoms can vary widely based on dose, route of administration, and individual factors. Most acute symptoms are transient and resolve within hours, but chronic use can lead to more persistent complications that require specialized management.