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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Original Article- http://painsandiego.com/category/complex-regional-pain-syndrome/