Is ketamine inhalation safe for medical use?

Safety of Ketamine Inhalation for Medical Use

Ketamine inhalation is not considered safe for routine medical use due to significant risks including respiratory complications, emergence reactions, and potential for abuse, with FDA labeling specifically cautioning against its use in procedures involving the pharynx, larynx, or bronchial tree without appropriate airway management. 1

Safety Concerns with Ketamine Administration

• Ketamine should only be used by or under the direction of physicians experienced in administering general anesthetics, maintaining airways, and controlling respiration 1
• Pharyngeal and laryngeal reflexes remain active with ketamine, making it unsuitable for use alone in procedures involving the pharynx, larynx, or bronchial tree 1
• Mechanical stimulation of the pharynx should be avoided when ketamine is used alone 1
• Resuscitative equipment should always be readily available during ketamine administration 1

Respiratory Considerations

• Ketamine can cause increased upper airway secretions, which may worsen respiratory symptoms in patients with underlying conditions like COPD 2
• When administered intravenously, ketamine should be given over a period of 60 seconds to avoid respiratory depression or apnea 1
• Muscle relaxants, with proper attention to respiration, may be required when ketamine is used for procedures involving the pharynx, larynx, or bronchial tree 1
• While ketamine generally preserves pharyngeal and laryngeal protective reflexes and can lower airway resistance, proper monitoring is still essential 3

Cardiovascular Effects

• Ketamine produces a dose-dependent increase in heart rate, blood pressure, and cardiac output through stimulation of the sympathetic nervous system 4
• It should be avoided in patients with ischemic heart disease, cerebrovascular disease, or hypertension due to its cardiovascular stimulant effects 4
• In patients with sepsis or critical illness, the hemodynamic response to ketamine may be blunted or even reversed 4

Neurological Considerations

• Ketamine can cause emergence reactions including hallucinations, memory defects, and panic attacks 5
• An increase in cerebrospinal fluid pressure has been reported following ketamine administration, requiring extreme caution in patients with pre-anesthetic elevated cerebrospinal fluid pressure 1
• Benzodiazepines can be used to mitigate the psychotropic side effects of ketamine 5

Special Population Considerations

• Ketamine has not been established as safe for use in pregnancy, including obstetrics (either vaginal or abdominal delivery) 1
• Safety and effectiveness in pediatric patients below the age of 16 have not been established 1
• Dose selection for elderly patients should be cautious, usually starting at the low end of the dosing range 1

Risk of Abuse and Long-term Effects

• Recreational use of ketamine is increasing, with additional risks including bladder and renal complications, persistent psychotypical behavior, and memory defects 5
• Ketamine has become popular as a party drug, with users potentially experiencing unpleasant flashbacks even weeks after the drug has been eliminated from the body 6
• Chronic use can result in impaired verbal information processing, cystitis, and cholangiopathy 7

Clinical Monitoring Requirements

• Close monitoring of patients receiving ketamine is mandatory, particularly for CNS, hemodynamic, renal, and hepatic symptoms, as well as signs of abuse 5
• Consider capnometry to provide additional information regarding early identification of hypoventilation during ketamine administration 8
• Pulse oximetry should be used in patients at increased risk of developing hypoxemia, such as when high doses of drugs are used 8

While ketamine has valuable applications in emergency medicine, anesthesia, and pain management, its inhalation route specifically presents significant safety concerns that limit its routine medical use. The FDA labeling and clinical guidelines emphasize the need for specialized medical supervision and appropriate airway management when ketamine is administered, particularly via routes affecting the respiratory system.