Dexamethasone and neurotoxicity

[chmd]

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We have a great orthopod who no longer wants single shot brachial plexus blocks for her inpatients mainly because the blocks cease working at 3am and the patients perceive a great deal of pain at that point -- and so does the orthopod when she gets paged. She would prefer BP catheters but those can be very time consuming and not everyone can do them well yet.

She liked the idea of dexamethasone and I have used it in the past but some of my colleagues fear the neurotoxicity of that additive especially in light of emerging evidence they saw at the ASA recently.

I'm not aware of any concerning data. Anyone else - especially from recent ASA? Btw we don't carry buprenorphine and clonidine is unconvincing I think.

 

[excalibur]

We have a great orthopod who no longer wants single shot brachial plexus blocks for her inpatients mainly because the blocks cease working at 3am and the patients perceive a great deal of pain at that point -- and so does the orthopod when she gets paged. She would prefer BP catheters but those can be very time consuming and not everyone can do them well yet.

She liked the idea of dexamethasone and I have used it in the past but some of my colleagues fear the neurotoxicity of that additive especially in light of emerging evidence they saw at the ASA recently.

I'm not aware of any concerning data. Anyone else - especially from recent ASA? Btw we don't carry buprenorphine and clonidine is unconvincing I think.

Didn't attend recent ASA. Don't know what they said. Know from a colleague who attended sessions where presenters were advocating use of 2 mg PF decadron in PNB's. Can't comment on sessions regarding neurotoxicity. A search on SDN and recent literature will show several articles regarding the potential neurotoxicity of Dexamethasone and other additives. You can draw your own conclusions.

If your partners and you don't want to use decadron and you can't get buprenorphine and you want to make the orthopod happy, you guys better get proficient at catheters rapidly

 

[pgg]

I went to one session at the ASA where the presenter strongly argued against 4+ mg of dexamethasone because of lack of data, not data showing toxicity. He advocated 1-2 mg dexamethasone + 300 buprenorphine + 25 clonidine. Claimed 40 hours for brachial plexus blocks. Did not comment on nausea.

I have never been impressed with clonidine in any PNB, ever. I might start trying 100 or less of buprenorphine sometime.

For now I still use 4 mg dex without buprenorphine or clonidine.

I'm curious about what evidence was presented re: neurotoxicity at the ASA though.

 

[lane]

A recent article stated that dexamethasone caused no neurotoxicity; rather, the prolonged exposure to local anesthetic exposed the nerve to any damage. So long as the dexamethasone is preservative free (a tan bottle where I practice as opposed to a red/blue bottle) it shouldn't cause any damage. I'll try to dig up the article

 

[BLADEMDA]

Williams BA, Hough KA, Tsui BY, Ibinson JW, Gold MS, Gebhart GF.
Neurotoxicity of adjuvants used in perineural anesthesia
and analgesia in comparison with ropivacaine. Reg Anesth Pain Med.
2011;36:225Y230.



Our group recently showed 50% neuronal cytotoxicity in
nondiabetic cultured primary sensory neurons after 24-hour
exposure to 0.25% ropivacaine, whereas clinically relevant
concentrations of clonidine, buprenorphine, dexamethasone,
and midazolam were nontoxic.7

 

[Oggg]

The regular dexamethasone has benzoyl alcohol I believe, which could be neurotoxic. Get your pharmacy to order it now.

I believe there is a very recent article that says claims that 10mg IV Dex == 10mg perineural Dex. I haven't read the full article yet, but it's bullocks.

 

[Intubate]

Dexamethasone has been used literally millions of times on lumbar, thoracic, and cervical nerve roots for pain procedures. If there was a pattern of neurotoxicity, I think we would have have found it over the last several decades. In addition, for these pain procedures, its used in much higher doses and much, much higher concentrations. If anything, its conceivable (maybe a stretch) that dexamethasone is protective, or maybe therapeutic in the event of nerve trauma during the block.

 

[BLADEMDA]

PF dexamethasone is safe to use as an adjuvant for nerve blocks. We are well over several thousand nerve blocks with PF decadron. That said, I limit my PF decadron to 2mg per block (sometimes I use only 1 mg) in Diabetic patients. In addition, my standard decadron dose (PF) in non diabetics is 4 mg per block. There is little to be gained by doubling the decadron to 8 mg per block (maybe an hour or two at most). Instead, add a little Buprenorphine to your mixture as that should provide an additional 4 hours of postop analgesia after the motor block wears off.