Ketamine provides relief from treatment resistant mood and anxiety symptoms in close to 75% of cases, sometimes hours after a single infusion. Cambridge Biotherapies offers intravenous ketamine therapy for the treatment of depression, anxiety, post-traumatic stress disorder (PTSD), and obsessive compulsive disorder. Our mission is to deliver the highest quality care in a warm, supportive, and welcoming environment.
What is Ketamine?
Ketamine is a fast-acting antidepressant. It is a selective antagonist of the NMDA receptor and primarily affects the glutamate neurotransmitter system. The more commonly used antidepressants such as Zoloft, Wellbutrin, and Cymbalta, affect the neurotransmitters serotonin, dopamine, and norepinephrine. While these medications can take 4-6 weeks to achieve their full effect, ketamine acts much faster and can substantially reduce symptoms in hours or days rather than weeks.
How Does Ketamine Work?
According to the monoamine hypothesis, depressive symptoms are mainly related to a deficit in the availability of monoamine neurotransmitters, and most antidepressant drugs are believed to modulate these neurotransmitter systems (e.g., norepinephrine, dopamine, or serotonin). The therapeutic effects of these common antidepressant medications emerges only after 4-12 weeks of treatment, so pharmacological agents like ketamine that exert rapid antidepressant effects are desperately needed in clinical practice.
When used to treat depression and anxiety, ketamine has a different mechanism of action from standard antidepressants. Ketamine acts by blocking N–methyl–d–aspartate (NMDA) receptors in the brain, which interact with the neurotransmitter glutamate. A 2018 article in the journal Nature concluded that depression is associated with increased burst activity in a part of the brain called the lateral habenula, which is essentially the “anti-reward center.” Blocking NMDA receptors in the lateral habenula, thus, is what leads to the rapid antidepressant actions of ketamine. The resulting chemical changes in the brain are not yet fully understood, but likely involve ketamine-induced gene expression and signaling cascades that act long after the drug has been eliminated from the body.
Is Ketamine Effective?
Yes. Ketamine has been shown across multiple studies to have an immediate and marked antidepressant effect for the majority of patients. It can substantially reduce or eliminate the most acute and distressing symptoms of depression, such as thoughts of suicide. In numerous research studies worldwide, the administration of six doses over several weeks has yielded a pronounced effect on severe depression, including otherwise treatment-resistant depression, although the duration of this effect varies substantially among individuals. Repeated administration produces a more pronounced and longer-lasting effect.
Of note, ketamine has been shown to induce neurogenesis—the creation of new nerve cells in the brain—beginning within two hours of administration. Exposure to ketamine has long-lasting effects on the activation of newly-formed neurons in a part of the brain called the hippocampus, which regulates the formation of new memories.
At Cambridge Bio-therapies we remain vigilant about current research, and work closely with other treatment providers to create individual treatment plans.
Side Effects of Ketamine
Because ketamine has been used for many years in other medical settings, there is much more known about its safety than is typical for cutting-edge treatments. Across studies, adverse side effects are uncommon, however, some patients do report nausea during treatment which can be quickly alleviated using an IV medication called ondansetron. The most common adverse effects include drowsiness, dizziness, poor coordination, and feelings of strangeness or unreality during the infusion. Variation in blood pressure during treatment can occur, however, these variations are not often clinically significant.
Ketamine at higher doses has been used as an anesthetic for many years, particularly for children and in mobile surgical units, because it generally does not suppress breathing and has such a favorable side effect profile. It is on the World Health Organization’s List of Essential Medicines, which includes the safest and most effective medicines needed in most health systems.
The long-term side effects of ketamine are not fully known, but there have been no reports of significant medical concerns associated with the use of sub-anesthetic doses administered for a limited time, as in the treatment of depression.
Highly qualified medical professionals monitor physical and mental side effects during treatment at Cambridge Biotherapies.
How is Ketamine Administered?
Ketamine is administered through an IV over a period of 40 minutes, by highly qualified nurses in a comfortable setting. The dose is determined by the patient’s weight and is substantially lower than the doses used for anesthesia. The amount of ketamine administered to treat depression and anxiety is not enough to cause a loss of consciousness, so patients remain awake.
During the infusion, some patients experience odd perceptions, like seeing bright colors. Some report what is referred to as a "dissociative", or "out of body" experience. Most patients tolerate the experiences with no trouble, and many even find them pleasant. Once the infusion is complete, the dissociative effects of the drug rapidly dissipate.
The most thoroughly studied treatment schedule is six infusions over 2-4 weeks. The experience of the first infusion is typically the most intense, and patients require variable amounts of time to feel fully comfortable resuming their normal activity. After later infusions, patients generally leave the office within 30 minutes following the infusion and feel quite normal.
Ketamine & Reduction of Suicidality
Based on three open-label studies, ketamine was found to be effective at reducing suicidality in treatment resistant depression (TRD) patients. Suicidal ideation in TRD patients improved in numerous cases after only a few minutes of ketamine infusion and remained stable for up to 4 hours post–infusion.
These findings have been replicated in patients with treatment-resistant bipolar depression by Zarate et al. In this randomized double-blind placebo-controlled crossover study, 79% of subjects were reported to respond to ketamine at some point during the 2-week trial, although the effects of ketamine waned from days 7-10 and there was no significant difference compared to placebo at that point.
Ketamine & Alcohol Abuse
Interestingly, a family history of alcohol dependence seems to predict a rapid initial antidepressant response to an NMDA receptor antagonist, and this may serve as a useful marker for response to ketamine. It has been suggested that NMDA receptors are one of the targets linked to the action of ethanol, and genetic alterations of NMDA receptor subunits have been associated with the emergence of alcohol dependence.
Ketamine is not currently covered by insurance providers. Please contact us to discuss the cost of treatment.
Cambridge Biotherapies is an official member of the American Society of Ketamine Physicians - www.askp.org/directory/
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