Ketamine Infusion Therapy

Ketamine

Ketamine, initially developed in the 1960s by Dr. Calvin Stevens, was originally intended as a safer alternative to phencyclidine (PCP), a dissociative anesthetic. It was first synthesized by Parke-Davis (now a part of Pfizer). Ketamine quickly found use in the medical field as an anesthetic due to its ability to induce a trance-like state while maintaining vital functions.

Throughout the 1970s and 1980s, ketamine gained popularity in veterinary medicine. Its unique properties, including rapid onset and relatively short duration, made it a valuable tool. However, ketamine’s dissociative effects led to its recreational use, earning it the moniker “Special K” in party circles. Concerns over abuse potential led to its classification as a Schedule III controlled substance in the United States in 1999.

Side effects, such as elevated blood pressure and heart rate, prove advantageous in maintaining adequate cardiac output, particularly in cases of head injuries where preserving cerebral perfusion is critical. As a result, ketamine found application in emergency and wartime medicine.

Ketamine’s remarkable safety profile allows for its use in patients with asthma and airway disease. Consequently, the World Health Organization (WHO) has classified ketamine as an essential medicine for many decades.

Emergence of Ketamine Infusion Therapy

Studies in the early 2000s, including those by Dr. John Krystal and Dr. Carlos Zarate, demonstrated that ketamine could rapidly alleviate symptoms of depression, even in individuals who had not responded to traditional antidepressants.

In 2019, the U.S. Food and Drug Administration (FDA) approved a ketamine-derived nasal spray called SPRAVATO® (esketamine) for treatment-resistant depression.

Ketamine infusion therapy clinics began to appear across the United States and around the world, offering treatments for mood disorders and chronic pain.

Dosing

Ketamine infusion therapy utilizes racemic ketamine in sub-anesthetic doses. This means ketamine is administered at levels below what’s needed for anesthesia. It’s a safe and effective approach that provides rapid relief for conditions like depression, anxiety, PTSD, and chronic pain.

Efficacy

Treatment-Resistant Depression (TRD): Approximately 70% of patients with TRD experience a significant reduction in depressive symptoms after a series of six ketamine infusions.

Suicidal Ideation: Ketamine has demonstrated rapid reduction in suicidal ideation. In some studies, up to 50-60% of patients with suicidal ideation experienced a significant decrease after ketamine treatment.

Bipolar Disorder: Ketamine may be more effective for managing the depressive phase of bipolar disorder, but the response rates can vary widely.

Contraindications

• Active psychosis or severe mental illness
• Uncontrolled hypertension
• Severe cardiovascular conditions
• Recent heart attack
• Elevated intracranial pressure (e.g., from head injury or tumors)
• Active substance use disorder
• Pregnancy
• Allergy/hypersensitivity to ketamine
• Severe liver or kidney dysfunction
• Medications with potential interactions

Medical vs. Recreational Use

Ketamine can have negative effects, especially when taken outside clinical settings and in different amounts. According to the 2020 Global Drug Survey, around 15.9% had used ketamine in the last year. This was a significant increase compared to previous years.

While overdosing on ketamine alone is rare, it can still cause problems when used recreationally. People are more likely to have accidents when using ketamine outside of medical settings. There have been reports of sexual assaults where individuals were unable to give consent or defend themselves due to ketamine’s dissociative effects.

Metabolism and Excretion

Ketamine metabolism primarily occurs in the liver, where it undergoes enzymatic transformation, resulting in various metabolites, with norketamine being the most prominent.

Typically, in the blood, ketamine and its metabolites are detectable within minutes after administration, with peak levels achieved during the infusion. After discontinuation, the drug and its metabolites begin to decline, with a half-life ranging from 2 to 4 hours.

In urine, ketamine and its metabolites are detectable for a relatively short period, typically within 1 to 3 days after administration, and up to 14 days with repeated use.