Abstract
Dear Editor:
The incidence of depression in intensive care unit (ICU) patients is high, approximating 50%, with the incidence and severity much higher among terminally ill patients such as those found in a cancer ICU. Many factors can cause depression in these patients, including pain, suffering, a sense of hopelessness, loneliness, and fear of death and the unknown. Those with a history of chronic depression are more susceptible to having a severe recurrence. Many terminal patients who become depressed want to end their life and as a result request euthanasia. In the last 15 years, we have had over 15 patients in our cancer ICU requesting an end to their life.
In seriously ill patients the response to current antidepressants, such as selective serotonin reuptake inhibitors (SSRIs), is slow. Additionally, these drugs may be ineffective secondary to poor absorption from the gastrointestinal tract. The patients in our ICU were started on an intravenous combination of low-dose ketamine with fentanyl and concurrently started on low-dose desipramine. The response was rapid, within several hours. These patients had their depression improve despite deterioration in physical status secondary to terminal disease. We have found this combination of medications to have a high success rate with noticeable symptom improvement for the remaining final days of life. Most of the patients require ketamine (6–10 mg/hr), fentanyl (20–30 μg/hr), and desipramine 10–25 mg daily depending on the severity of their disease.
Recent papers suggest that ketamine is an effective rapid acting anti-depressant.2,3 It is also a useful analgesic without anti-cholinergic side effects. The mechanism of action of ketamine is via blockade of NMDA receptors and glutamate pathways and the possible up-regulation of AMPA receptors. It also decreases the pre-synaptic reuptake of dopamine, norepinephrine and serotonin. Further studies should be undertaken to more fully understand its antidepressant qualities.