Ketamine IV vs Nasal Spray or Sublingual

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Patients ask me to compare IV ketamine to other routes of administration such as intranasal or sublingual. No one has done comparisons. Even if they had, every person is different and may have several pain syndromes.

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I have outlined one case below. One disadvantage of IV ketamine is the cost and the need to schedule for an IV treatment with your physician often weeks in advance. For some, this may mean setting aside two weeks to travel and make other arrangements. The alternative is carrying this low cost medication in your pocket and using as needed to relieve pain when you have pain, or to prevent pain when you know your activity will flare it.

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Ketamine is an important medication for pain.  It is considered a third line choice for pain relief, but it is almost a first line choice for Complex Regional Pain Syndrome, CRPS  – the old term is RSD. And I prescribe it for other conditions that have been refractory to treatment. But, far more than any other pain syndrome, pain from CRPS can be flared by emotional stress or minor injury and it can spread to other areas.

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Ketamine is a short acting medication. It is both analgesic and anti-inflammatory.

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Opioids create pain; ketamine not only relieves pain, it also relieves inflammation. In fact, opioids may prevent ketamine from helping at all.

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A small number of pain specialists in the USA, most at university centers, provide IV ketamine for CRPS. Not all people respond. A lucky few may get months of pain relief, but may require monthly boosters, i.e. it may be a short acting medication only during the infusion or it may offer relief for weeks or months but not years. I do not believe anyone has published comparisons showing duration of effect.

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I view ketamine as a short acting medication that requires other combination medications to “clamp” the relief and prevent pain from recurring.

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Here is a case report posted a few years ago of my patient who had 8 months of relief from IV ketamine. It was given 24 hours/day for 5 days in May 2007, followed by four hour IV boosters two days every month. Unfortunately all ketamine stopped having any effect after 8 months. I then added multiple medications that were selected because of specific mechanisms — no opioids, no ketamine — and she has been pain free since December 2009 on a single drug.

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CASE REPORT

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Today was the 5th visit in the last two weeks with an out of state patient who has had CRPS since 1999. She also has sciatic neuropathy, chronic lumbar pain after 360 degree spinal fusion, shoulder pain, and two types of headache. Medications are now significantly helping all pain syndromes.

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Before seeing me, she had had a total of 9 infusions of IV ketamine most of them given at doses of 300mg/hr — a very high dose. She had no side effects from ketamine. One of those infusions was given for 6 days over 4 hours each day. She had failed a lidocaine infusion at high dose. A spinal cord stimulator was reprogrammed 10 times, but only made pain worse.

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I then started her on a combination of medications. With addition of the first new medication, she had 50% improvement in the first 24 to 36 hours, that lasted beyond the relief from nasal ketamine that was also started. Unfortunately, on day 8, she and another family member, came down with a virus that causes headache and severe vertigo. Nevertheless, all pain is markedly better.

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With ketamine she is able to reduce pain down to 1 on a scale of 10 for a few hours. Best of all she can carry it with her and use it as needed. She no longer needs to take two weeks out of her life to schedule IV ketamine infusions.

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It will take almost 3 months to slowly increase the other medications we started. Hopefully this combination will “clamp” the pain and prevent it from increasing so that she may become pain free without needing ketamine.

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After that, if she is able to become pain free, the plan is that we will then be able to slowly remove most of the new medications we started this week and still maintain relief of pain. I will see her again in the future.

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The material on this site is for informational purposes only,

and is not a substitute for medical advice,

diagnosis or treatment provided by a qualified health care provider.

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Please understand that it is not legal for me to give medical advice without a consultation.

If you wish an appointment, please telephone my office.

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For My Home Page, click here: 

Welcome to my Weblog on Pain Management!

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RSD – CRPS – Complex Regional Pain Syndrome – Long Distance Patients

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I see long distance patients in my office who generally come for a two week stay, and I wish to encourage their comments on this page. I am sorry I did not post this page for them sooner.

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Most people I see have been tried on every common approach to treatment for Complex Regional Pain Syndrome, CRPS. I prescribe most of those therapies as well, but I also use an expanded number of neuropharmacology approaches. Some of these are outlined in the case report I filed in March 2010. Patients have sent comments on their progress, and others have made comments on spinal cord stimulators, below.

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In my opinion, it is important to use rational polypharmacy. When pain is intense, it is important to look at more than one mechanism. Once pain comes under control and remains at zero, then we can slowly begin to taper off one at a time.

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The following describe two of the several mechanisms of interest to me.

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NMDA Antagonists

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The glutamate-NMDA receptor is profoundly important in controlling pain pathways. It is responsible for tolerance to medication and centralization of pain. Research in France has shown that with chronic pain in persons with CRPS there is an increase in NMDA receptors in the central nervous system. After pain control, the increased number of NMDA receptors returns to normal.

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With persistent pain or chronic depression, glutamate increases and becomes excitotoxic. When it attaches to the NMDA receptor, it causes calcium to enter the neuron, creates free radicals, and kills neurons. This leads to brain atrophy and potentially memory loss.

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The goal is to block this mechanism. I use three medications that work at this level.

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Morphinans – Glial dysregulation of pain pathways

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Another important area of focus for me are the morphinans which means morphine-like. Their mechanism of action is at the microglia, the immune cells in the central nervous system. There is important new research on glial dysregulation of pain pathways. Once primed and activated by pain, the next pain insult causes glia to react harder, faster and longer perpetuating pain with cascades of pro-inflammatory molecules. Glial research on pain is very recent, very new, very important, and is a rapidly growing  body of science. It offers an entirely new paradigm for treatment of chronic pain.

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The Reflex Sympathetic Dystrophy Syndrome Association library has

many research articles that you may wish to read.

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I am grateful to be invited to their workshop on activated glia.

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Contributing Factors

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I look at the whole person, review all of their medications including their vitamins and botanicals, toxicity and adverse interactions with medication. I check the blood level for 25(OH) vitamin D (done at ARUP labs), parathyroid hormone (PTH) if not already done, and stress the importance of anti-inflammatory diet, fish oil, and adequate levels of vitamin D3.

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Spinal cord stimulators – controversy

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A recent Wall Street Journal article discusses some of the controversy of interventional techniques in this evolving specialty and mentions that some studies are underway to show efficacy. Implantable devices are controversial “and questions remain about the appropriateness of their use.”

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In April 2010, new guidelines were published, updating earlier ones from 1997: Practice Guidelines for Chronic Pain Management: An Updated Report by the American Society of Anesthesiologists Task Force on Chronic Pain Management and the American Society of Regional Anesthesia and Pain Medicine.

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“Spinal cord stimulation: One randomized controlled trial reports effective pain relief for CRPS patients at follow-up assessment periods of 6 months to 2 yr when spinal cord stimulation in combination with physical therapy is compared with physical therapy alone (Category A3 evidence).”

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A3 evidence was defined as: “The literature contains a single randomized controlled trial.”

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The guidelines had no references, nor did it indicate how old that study was. A short two year followup and a single limited study after more than 32 years of implanting these devices should call for more research.

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I do not recommend spinal cord stimulators as there is no research showing long term efficacy and no quality evidence showing they are superior treatment. Success declines after placement and that may occur the first day. In fact, there is one long term 5 year European study showing no efficacy after two years. A surgical nurse offered her frightful surgical experiences in comments below. Any invasive procedure may trigger pain in a person with CRPS and removal of the device does not necessarily relieve pain.

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Often patients are not aware that alternatives exist and are not given fully informed consent on the stimulators. Those risks include increased pain with any invasive procedure in persons with CRPS, paralysis, spasticity, infection, scarring, potential flare into generalized CRPS pain. The fact that these leads may be permanent  - they can never be removed – means that person can never undergo MRI scans in future even if they should have cancer or stroke. The leads may become scarred into nerve tissue and tethered to the spinal cord.

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A colleague, a prominent Harvard trained anesthesia pain specialist in practice for 40 years, declines to recommend stimulators or pumps for that reason: there is no long term data proving efficacy.

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Complications of spinal cord stimulators should be published. Perhaps they exist. If anyone has seen them, please advise me. I tend to see the complications or the failures, but those who place them and the corporations that fund them should have a special obligation to study the complications and the long term benefits. Having a spinal cord stimulator does not prevent use of other medication but it may add to the burden of pain to overcome. Nationally there should be an audit of stimulators placed, with patient outcomes including complications and number of revisions made. The risks are too grave not to require this and the cost is too high if there is no lasting efficacy.

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The excerpt below is from a 2003 review on spinal cord stimulation (SCS) for Complex Regional Pain Syndrome. It may be outdated, however Medtronic failed to provide me with any long term studies when requested:

“The use of SCS for the treatment of pain in CRPS (including RSD and causalgia) has been reported in the literature for over 25 years. The consensus opinion from experts suggests that SCS should be considered in the treatment algorithm when conservative or traditional therapies have failed. However, such considerations are not based on reliable evidence generated through well-designed randomized controlled trials. To date, there has not been a systemic evaluation of the existing literature concerning the efficacy of SCS for patients with CRPS.”

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For those wishing to come to San Diego for two week stay, please see information on long distance patients in banner at top of page.

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~~~~~The material on this site is for informational purposes only, and is

not a substitute for medical advice, diagnosis or treatment provided by a qualified health care provider. ~~~~~

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