By Eva Briggs, MD
As a physician, I’m always learning with continuing medical education. Recently some CME popped about ketamine and its use to treat mental health disorders.
I had a little familiarity with ketamine as an anesthetic agent — but not a lot since it’s not something we use at the urgent care.
It’s also been used as a recreational drug whose street names include Cat tranquilizer, Cat valium, Jet K, Kit Kat, Purple, Special K, Special La Coke, Super Acid, Super K and Vitamin K.
Ketamine was first synthesized in 1962. In 1970 it was approved by the FDA as an anesthetic and analgesic (pain-relieving) medication. It acts as a dissociative anesthetic that distorts perceptions of sight and sound. It’s short-acting but makes the user feel disconnected. It may cause hallucinations.
Mental health disorders for which ketamine has been studied include depression, anxiety, post-traumatic stress disorder, obsessive-compulsive disorder, bipolar disorder in the depressed phase and substance abuse disorders.
Ketamine generally acts more quickly than antidepressant drugs, often alleviating suicidality within 24 hours.
Currently it’s reserved for patients who have failed at least two different antidepressant drugs that were tried at adequate doses and duration. When given in a controlled setting it’s not habit-forming.
Ketamine blocks the NMDA receptor in the brain. The NMDA receptor inhibits the release of the neurotransmitter chemical glutamate. In the presence of ketamine, glutamine levels surge. It’s thought that this surge leads to the rapid antidepressant effect.
Advantages of ketamine include that it’s widely available. It’s easy to administer as it comes in oral, IV and intranasal forms. In appropriate doses it does not reduce heart rate, respiratory rate or blood pressure. The dose used, 0.5 mg per kg, is far lower than the lethal dose of 11-12 mg per kg.
Ketamine is contraindicated in some patients. Because it can induce or worsen mania, it should not be used in bipolar patients in the manic phase. It may cause psychosis and should be avoided in actively psychotic patients. It should be avoided in patients with substance abuse, uncontrolled high blood pressure, pregnancy or breastfeeding and patients taking monoamine oxidase inhibitor medicines. Other contraindications are a history of seizures, brain aneurysms, thoracic aneurysms or a previous bad reaction to ketamine.
The most common side effect is nausea and vomiting due to dizziness. Patients can be pre-treated with anti-nausea medicines if at risk. Because ketamine often causes dissociation patients may experience unusual sights or sounds. Some people find this pleasant or euphoric, but others dislike this sensation. Other potential reactions include sedation, fatigue, elevated blood pressure, dizziness, blurred vision, nystagmus (eyes jerking back and forth) and rarely confusion.
The dose of ketamine is easiest to control when given via the IV route, typically infused over 40 minutes. The form approved for anesthesia, called racemic mixture, is used off-label for mental health diagnoses and may not be covered by insurance. Ketamine can be given via the intramuscular route — typically one to three shots 15 minutes apart. Unlike an IV it can’t be stopped if the patient has a bad reaction and takes longer to wear off. There is a form of ketamine called S-KET that is covered by insurance. After administration patients remain in the office for two hours. The peak effect occurs about 15 minutes later than with the racemic form. Racemic ketamine can be made into a nasal spray by a compounding pharmacy but has expensive out-of-pocket costs. Oral or sublingual (under the tongue) forms have the lowest bioavailability and also likely high out-of-pocket cost.
S-ketamine, brand name Spravato, can only be given in certified Spravato treatment centers. Patients are monitored in the office for two hours. They are not allowed to drive home afterward and require transportation. For the first four weeks, Spravato is given two times per week. In weeks five to eight it’s administered twice per week. After that the maintenance dose is given once a week or once every other week.
Because the brain has increased neuroplasticity (ability to change) for the first day after receiving ketamine, psychotherapy can be very beneficial in the first 24 hours. The therapy can be done during or after the treatment. It’s particularly useful to help PTSD patients work through traumatic thoughts.
This article is just a brief summary about medical ketamine. If you think ketamine might be helpful, you will need to discuss this with an experienced mental health provider.
Eva Briggs is a retired medical doctor who practiced in Central New York for several decades. She lives in Marcellus.