Ketamine has been used as a safe anesthetic for close to 50 years. 8 years after it was produced in 1962, it was approved for use on human beings. The safety margin of ketamine proved important when soldiers were allowed to administer it to their injured comrades during the Vietnam War.
This was done in the field by people who were not necessarily trained anesthetists or even medical professionals. Apart from its anesthetic effects, this drug has been abused as a recreation and club drug.
The use of ketamine as an anesthetic has gone down significantly in many developed countries after more effective anesthetic drugs have been developed. But now there is renewed interest in this drug after researchers found it to be effective in the treatment of depression that is not responding to convention anti-depressant medications.
The journey of ketamine as an antidepressant
The first study group of patients who used ketamine for depression was in the year 2000. The initial study involved only 7 patients. Another study 6 years later found that 71% of patients with treatment-resistant depression improved and reduced symptoms of depression by up to 50%.
These encouraging results occurred within 24 hour of giving a single dose of ketamine infusion. Now compare that with the almost 4 weeks that conventional antidepressant drugs take to start showing any significant improvement. For some patients, no improvement is observed at all with the conventional antidepressant.
What research on ketamine has so far revealed
A single low-dose ketamine infusion is given in about 40 minutes. According to The Lancet – Psychiatry, severe depression signs and symptoms reduces for a few hours to up to 14 days after that single dose. Some severely depressed patients may not be very compliant in taking daily medications as is common with many anti-depressants. The Lancet compares this with the 3-4 weeks it would take for conventional antidepressants to offer the same effects.
Still, according to the Lancet, about a third of patients on these antidepressants do not respond to the treatment at all. In this regard, ketamine as an antidepressant is likely to be more convenient for some patients. The only challenge would probably be the need to visit a health facility for the infusion. But for patients whose ketamine antidepressant effects last for up to 14 days, this may not be an issue.
The fast and effective antidepressant effects of ketamine can also be a point in promoting patient’s compliance. This may create a window for counsellors to help the patient gain more insight and positive attitude to help them in the journey out of chronic depression.
Another point to note is that conventional treatment-resistant depression is managed by combining various medications and adjusting treatment regimen. This is likely to confuse the patient and the many different pills are more likely compromise the patient’s compliance to treatment.
Single drug treatments always offer superior compliance than multiple drug therapy.
One of the causes of major depression is chronic pain due to any of the longstanding health conditions. Ketamine has strong analgesic properties. The double effect of pain killing effects and antidepressant properties are further reasons for better patient compliance.
Ketamine is one of the drugs commonly abused for its dissociative and hallucinogenic effects. This non-medical use creates concern to authorities and for it to be used as an antidepressant calls for effective control measure. Other concerns include:
- Risk of tolerance. However, unlike the recreational ketamine, preliminary study results indicate that this is not likely to happen with the therapeutic doses used for depression due to the dose and frequency of use. But research is on to consider other routes of administration or prolonged infusions that will ensure small doses are given over a long period of time in an effort to reduce possible undesirable effects on the liver
- Daily users of ketamine are prone to cystitis. This painful condition can theoretically affect those using the drug for depression. This problem has however, not been seen with the therapeutic doses of ketamine used for pain management and the infrequent use in depression management.
- Patients with psychosis appear to have their symptoms exacerbated and so should not be given ketamine.
Ketamine and suicidal tendency
A good number of people on the usual antidepressant drugs have a suicidal tendency but this disorder has not been observed with ketamine use.
Ketamine and ECT
The use of conventional antidepressant used in major depression is often combined with electroconvulsive therapy (ECT). The benefits of ketamine are achieved without this unpleasant mode of treatment that requires an anesthetic.
The future of ketamine as an anti-depression agent
There are ethical and social concerns about the use of ketamine. Effective controls have to be in place to minimize its potential for abuse. Currently, its use is largely off-label which means different clinicians use it differently and many recommendations are based on studies.
More research needs to be done and pharmaceutical companies should look into the possibility of promoting it as an antidepressant. There is no doubt that ketamine offers hope for eligible patients with treatment-resistant depression.
Radvansky, B. M., Shah, K., Parikh, A., Sifonios, A. N., Le, V., & Eloy, J. D. (2015). Role of Ketamine in Acute Postoperative Pain Management: A Narrative Review. BioMed Research International, 2015, 749837. http://doi.org/10.1155/2015/749837