Ketamine for chronic pain is a fascinating treatment that promises much but still has many problems to be solved. It was first produced in the 1960s as a general anesthetic
It actually was derived from something called phencyclidine which was another general anesthetic which then became known as PCP or angel dust.
It became a highly sought after drug of abuse. Ketamine was produced to try and find another general anesthetic which would not have quite the highly addictive qualities.
It’s still very similar to phencyclidine and this is where a lot of its problems come from. The primary issue is that it creates psychological dependency.
It is still a really interesting drug because it produces dissociative anesthesia. This state is when you and your conscious thoughts float off somewhere else. In high doses, it’s a general anesthetic and puts you to sleep. But in low doses, it has this effect of separation or dissociation of your mind from all the trials and tribulations of your body.
Its primary effect, which is where it is such a fascinating substance, is that it reduces the action of the NMDA receptor. The NMDA receptor is the receptor that’s found on many nerve synapses – where one nerve transfers information to another.
It is very well recognized that the NMDA receptor is the one that causes central sensitization. When that receptor is turned up, messages which are quite benign from your body become turned up and you perceive them as increased pain.
What ketamine does is it is an antagonist of the NMDA receptor, it turns down this receptor down. It works for a whole group of painful conditions which are very difficult to treat, like CRPS, neuropathic pain, and central sensitization.
It also increases the descending inhibition. This is a pathway in your body where you turn down the sensitization from your brain. It’s called the descending inhibitory pathway.
Ketamine has been shown to increase the descending inhibition. It acts on all the areas of the brain: the anterior singular cortex, the prefrontal cortex etc. which are known to produce chronic pain.
It’s potentially a very exciting drug, but it has real problems because of its addictive and mind-altering properties.
Ketamine had been used on diabetic phantom limb pain, CRPS, trigeminal neuralgia, postherpetic neuralgia (chronic pain from shingles) fibromyalgia, and severe migraines ( which are another central pain problem.)
There have been studies done on its ability to treat all these incredibly difficult to control chronic pain problems. Most of the studies have shown ketamine infusions provide excellent short term pain relief, which is good.
However, that’s not really all you want if you’re trying to treat a chronic pain problem.
Ketamine is administered via intravenous infusion. The problems with infusions are firstly that they’re expensive – the person has to be brought into a medical facility and be given the infusion slowly. The second problem is that there’s been no uniformity. Different doses have been tried and there’s no consensus on what the best dose per kilogram of weight is, or the best speed of dose infusion is.
What has been noted is that the longer you take to give the infusion, the longer its beneficial effects last. This means people will come in and have an infusion given to them over many hours.
In general, the longest lasting pain relief people have noticed is around four to six weeks. However, this isn’t always the case, and the results can be quite unpredictable.
After the effect wears off, you have to repeat the procedure. So the major problems are that it’s intravenous, it’s expensive, there’s no consensus, and it only works for short term. The really big problem, though, is that it’s not a benign medication.
It can have quite significant effects on the body and mind. The more injections you’re given, the more significant the side effects tend to become.
And unfortunately, the more infusions you’re given, the less effective the treatment becomes. The side effects are that it acts on your brain where it often causes confusion and paranoia. People have described themselves as feeling ‘loopy’ and ‘spaced out.’ This effect can continue all the way to some people getting convulsions.
It can also cause skin rashes and it may go all the way to causing anaphylaxis, which is a major reaction life threatening reaction. It has an effect on the bladder where it causes inflammation, sometimes cystitis. When it’s mild, this makes people want to go to the bathroom a lot. But in an extreme form, it may cause bleeding and longterm problems for the bladder.
Ketamine infusions can cause problems with your heart where you may get funny rhythms or drops in your blood pressure.
This can be minor or major, it can cause nausea, vomiting, diarrhea and liver issues.
There’s a lot of potential problems with the medication and its benefits are short term. U
However, when nothing else works, it can significantly help a small group of people who have the most terrible pain arising from damage to nerves and central sensitization.
The consensus of expert opinion is that it’s something which, when carefully given, in well-selected patients is effective in the short term.
However, it has potentially significant side effects. In reality, the number of severe side effects is not large. It’s something that is not about to be phased out, but it’s by no means a magic bullet for neuropathic pain.
There’s one other really interesting beneficial effect of ketamine and that is it works in depression when nothing else does.
There’s been a preparation of ketamine which you puff up your nose as at transmucosal treatment. It’s been approved by the FDA for use in depression which has not responded to any other treatments.
Again, it comes with all the significant problems that we’ve discussed. In terms of chronic pain, depression can be a significant part of chronic pain. To find a medication which both works on neuropathic pain and on depression is potentially exciting.
Ketamine does need a lot more work to be done before it really fulfills on its initial promise as a safe, effective treatment for chronic nerve pain.
Its use needs to be carefully monitored and it needs to be used very sparingly.
If you’re interested in non-drug solutions for chronic pain, and the mental techniques people have used to their life, and their pain, back under control, > (opens in a new tab)”>here’s where to find out more >>