There is one thing almost all ketamine therapy patients have in common: they are taking daily medications to manage their condition. Ketamine therapy is growing in popularity for the treatment of mood disorders, such as depression, anxiety, PTSD and suicidal ideations. It is also proving successful in the treatment of chronic pain conditions such as neuropathic pain and fibromyalgia. Many people find relief from ketamine therapy, but others do not get the same benefit. One possible influence is the host of medications people take. This article will briefly review some medications that affect the way ketamine works in the body.
Competition in the Brain
Some medications prescribed for mood disorders are affecting the same pathways in the brain as ketamine. They may change the efficacy of ketamine, or how well it works. Therefore, they may actually delay and diminish or even boost the positive effects of treatment.
- Benzodiazepines, such as Xanax, Ativan and Klonopin are often prescribed for anxiety, sleep and even muscle spasm. Using this class of medication during the ketamine treatments will mean a longer time to seeing improved mood and more importantly, decrease the overall time of feeling better. Therefore, a booster will be needed sooner.(1) Fortunately, they do not interfere with ketamine treatments for chronic pain.
- Lamotrigine is used both for seizures and bipolar disorder. It works to decrease glutamate release in the brain, whereas ketamine works to increase glutamate. Studies show this direct competition decreases the positive effects of ketamine.(2)
- Lithium, a mood stabilizer used for bipolar disorder, enhances ketamine as they both stimulate the same signalling pathway in the brain. Lithium can improve anti-depressant effects and help protect against some side effects of ketamine.(3)
Competition in the Liver
The CYP2B6 Liver Enzyme:
The cytochrome P450 (CYP450) enzymes reside in the liver and one group, the CYP2B6, is the primary enzyme to break down ketamine to norketamine, the main metabolite. Some medications are also broken down by the CYP2B6 and can actually influence ketamine. What happens if that enzyme is either ramped up or down by other drugs? A study from 2001 explained how some drugs affect this enzyme and can change ketamine levels.(4)
- Orphenadrine (Norflex), a muscle relaxant, inhibits CYP2B6 and slows the breakdown of ketamine which increases the amount of ketamine in the body.
- Dexamethasone, a common steroid, actually induces CYP2B6 and speeds up the breakdown of ketamine. This decreases the amount of ketamine left in your system to work.
