Ketamine, developed in the 1960s as a dissociative anesthetic, is now repurposed for its effects on mood and chronic pain. It interacts with the N-methyl-D-aspartate (NMDA) receptor system in the brain, offering a rapid onset of action. This unique mechanism makes it a promising option for individuals who have exhausted standard treatment protocols. Ketamine therapy is highly regulated, requiring strict medical oversight and careful patient selection to manage risks and maximize benefits. Qualification is a complex medical determination based on diagnosis, treatment history, and overall physical health.
Primary Conditions Addressed
Ketamine therapy is commonly utilized for specific psychiatric and chronic pain conditions. The primary mental health indication is Major Depressive Disorder (MDD), especially when classified as treatment-resistant. Ketamine promotes synaptogenesis, the rapid formation of new neural connections, making it an option when other antidepressants have failed. It is also explored for Bipolar Depression, typically reserved for the depressive phase, requiring careful management to avoid triggering a manic episode.
Post-Traumatic Stress Disorder (PTSD) and severe generalized anxiety disorders are sometimes treated with ketamine on a case-by-case basis, often when depression is a co-occurring symptom. These applications are generally considered off-label, meaning they are outside the original Food and Drug Administration (FDA) approval for anesthesia. For chronic pain, ketamine is predominantly used for neuropathic pain, which originates from damaged nerves. Complex Regional Pain Syndrome (CRPS) is the most prominent example, where ketamine’s NMDA-blocking action helps reset the central sensitization driving the pain state.
Defining Treatment Resistance
Qualification for ketamine therapy is strongly tied to “treatment resistance” in both psychiatric and pain conditions. Treatment-Resistant Depression (TRD) is defined as failing to achieve a satisfactory response after trying at least two different classes of antidepressant medications. These trials must be adequate, meaning the medications were taken at a therapeutic dose for a sufficient duration, typically four to eight weeks, without significant relief.
This requirement ensures ketamine is not used prematurely when established, first-line therapies might still be effective. For chronic pain conditions like CRPS, resistance means standard interventions, such as nerve blocks, physical therapy, and pain medications, have not provided adequate relief. Ketamine is reserved as an advanced intervention for those who have failed to respond to these conventional approaches. This screening step ensures that the potential benefits outweigh the inherent risks for the individual patient.
Absolute and Relative Contraindications
Absolute Contraindications
Certain underlying health conditions can disqualify a patient, even with a qualifying diagnosis. Absolute contraindications mean treatment is generally prohibited due to severe safety risks. These often relate to the cardiovascular system because ketamine transiently increases heart rate and blood pressure by triggering a release of adrenaline-like compounds.
Absolute exclusions include:
- Uncontrolled hypertension (systolic pressure consistently above 160 mmHg or diastolic above 90 mmHg).
- Recent heart attacks, unstable angina, or severe coronary artery disease, due to the risk of increased myocardial oxygen demand.
- A history of active psychosis, schizophrenia, or schizoaffective disorder. Ketamine’s dissociative properties can exacerbate these conditions.
- Known allergy or hypersensitivity to ketamine.
- Pregnancy, due to a lack of safety data.
Relative Contraindications
Relative contraindications necessitate a careful risk-benefit analysis and close medical supervision. These conditions raise concerns but do not automatically prohibit treatment. An active substance use disorder, for example, typically requires a period of sobriety and ongoing screening due to misuse potential. Patients in a current manic phase of Bipolar Disorder are generally excluded, though treatment may be considered once their mood is stabilized.
Relative concerns include:
- Conditions that increase intracranial or intraocular pressure, such as glaucoma, as ketamine may temporarily raise these pressures.
- Significant liver or kidney impairment, as these organs are responsible for metabolizing and eliminating the drug.
- Untreated hyperthyroidism, which can enhance ketamine’s stimulating effects on the heart.
The Medical Screening Process
The process of moving from a potential candidate to an approved patient involves a comprehensive, multi-step medical evaluation. This vetting begins with a detailed consultation with a qualified medical provider, such as a psychiatrist, anesthesiologist, or pain specialist. The provider reviews the patient’s medical and psychiatric records, focusing on failed prior treatments to confirm treatment-resistant status. A physical examination is mandatory, paying particular attention to cardiac health and blood pressure regulation.
Patients are required to undergo specific pre-treatment laboratory tests to establish baselines and rule out underlying issues. These tests frequently include liver function tests and creatinine levels to assess metabolic and excretory organ health. Thyroid-stimulating hormone (TSH) levels may also be checked to rule out undiagnosed hyperthyroidism. A baseline urinalysis is sometimes performed to assess kidney function and check for pre-existing urinary issues, as prolonged ketamine use can cause bladder irritation.
Once medical clearance is granted, a rigorous monitoring protocol is implemented during the treatment session. The medical team continuously monitors vital signs, including blood pressure, heart rate, and oxygen saturation, to manage the drug’s cardiovascular effects. Due to the medication’s dissociative effects, patients must be observed post-treatment and require a responsible adult escort them home.