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Author Topic: INTRATHECAL (WITH PRESERVATIVE) MORPHINE  (Read 3370 times)

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sunny

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INTRATHECAL (WITH PRESERVATIVE) MORPHINE
« on: January 13, 2012, 03:44:24 PM »
Are there anyone who still use regular (with preservative) morphine for spinal anaesthesia?
In lot of countries the 'preservative free' morphine is almost impossible to get. The advantages of small doses of intrathcal morphine (say...200 mcg) can be really great in these countries.
Once diluted I really do not think regular morhine can be harmful. One ampuole of 10mg/ml morhine will get diluted more than 100 times by the time you take 200mcg and mix it with local anaesthetic mixture.
Please comment....
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yogenbhatt1

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Re: INTRATHECAL (WITH PRESERVATIVE) MORPHINE
« Reply #1 on: January 23, 2012, 07:03:30 PM »
Hi,
I have never used Morphine intrathecal. Because of its lack of availability.
How ever I have always used Buprenorphine  to 60 / 90 mcg along with my Bupivacain.I have used it by default in all cases over last more than 15 years or so.
This includes an LSCS  and IT fractures, and even my Caudal Blocks in children.
Once I was called by another anaesthesiologist, because his IT fracture patient had gone in post op respiratory arrest. He had injected about 150mcg. He took it in a 10ml syringe, so "about" 150 mcg. The old man of 79 went in respiratory arrest 3 hours after surgery.
We gave him Naloxone, 200 mcg stat and 200mcg in drip over 10 hours. He recovered instantly.
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jafo1964

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Re: INTRATHECAL (WITH PRESERVATIVE) MORPHINE
« Reply #2 on: January 25, 2012, 03:36:29 AM »
with a little bit of effort preservative free morphine can be accessed.
Brand name VERMOR
i can send u the company details if interested
I have used 250 to 300 mcg of morphine in spinals but am very judicious about the patient population. Usually healthy, fit, robust patients.
It is my standard practice to use buprenorphine in all my spinals. I use about 150 mcg. I have had only 1 case where the respiratory rate was 8/min but the patient maintained adequate minute ventilation and CO2 removal. No respiratory problems otherwise. About 10% of these patients suffer from PONV and it can be quite distressing in a select few, requiring multiple doses of ondansetron and multimodal therapy.
I also use buprenorphine epidurally in a dose of 300 mcg.
I find that buprenorphine intrathecal produces good to excellent analgesia, lasting 24 to 72 hours, in majority of the patients.

I theorotically disagree with the learned Dr. Bhatt's opinion regarding the use of Naloxone, although in his vast experience his observation may be absolutely valid.
So the theory is
Naloxone is an opiod antagonist and is most effective against pure opiods that are agonistic at the MU receptors. So works well with morphine, fentanyl and all phenopiperidines
Buprenorphine is a partial agonist - antagonist drug. Its agonist action is at the KAPPA receptor and anatgonist action at the MU receptor.
So since buprenorphine is already antagonsit at the MU receptor I wonder how adding another antagonsit is going to reverse action especially since naloxone is ineffective at the KAPPA receptor

The other worrying point about buprenorphine is the fact that this highly lipid soluble drug has a FAST IN - SLOW OUT action. SO it binds fast but has a very slow dissociation constant . Hence if you get into undesirable trouble it may be very hard to reverse it.

Hence i use buprenorphine with extreme caution in the
extremes of age &
patients who have compromised respiratory function

regs
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