Neuronal blockade with morphine. A hypothesis

Abstract

A patient with an apical lung tumour invading the brachial plexus (Pancoast's tumour) suffered from unbearable pain unmodijed by daily treatment with morphine 180 mg subcutaneously. An interscalene brachial plexus block was performed using a solution containing 5 mg morphine hydrochloride in 10 ml isotonic saline. Complete analgesia was obtained after 20 minutes, an effect which lasted for the next 36 hours. Neuro-axonal transport of morphine to the spinal cord may be the explanation of the eflect, an hypothesis which ought to be subjected to controlled trials.

Pre-incisional infiltration for pediatric tonsillectomy: A randomized double-blind clinical trial

“…Keeping with our previous published experiences with this particular anesthetic mixture, where surprisingly long duration of analgesia has been found after different types of surgery [26][27][28][29]. Co-administration of clonidine [30] and opioids [31] Pre-incisional infiltration for pediatric tonsillectomy 1339 together with local anesthetic solutions have been found capable of prolonging the duration of peripheral nerve blocks, but the observed period of analgesia following the use of the current mixture of local anesthetics, fentanyl and clonidine outlasts an additive or even a synergistic effect of the drugs used and instead infers a pre-emptive analgesic action [32]. Although pre-emptive analgesia has been validated in various experimental pain models, very few studies have been able to substantiate this concept in the clinical setting [2,33].…”

Occipital Nerve Blockade for Cervicogenic Headache: A Double‐Blind Randomized Controlled Clinical Trial

“…21,22 The addition of clonidine and opioids to local anesthetic solutions has also been found to prolong the duration of nerve blocks. [23][24][25] The observed period of analgesia following the use of the current mixture of local anesthetics, fen-tanyl, and clonidine may have resulted from a synergistic effect. Clonidine might interact with the immune system, resulting in reduced recruitment of macrophages and lymphocytes at the nerve site and a shift in the proportion of macrophages from the pro-inflammatory to the anti-inflammatory phenotype.…”

Nerve stimulator guided pudendal nerve blockversus general anesthesia for hemorrhoidectomy

“…Opioid medications added to local anesthetic solutions have also been shown capable of prolonging the duration of peripheral nerve blocks. 19,20 There are several limitations associated with the PNB technique and study design. First, despite improved precision of nerve blocks achieved with nerve-stimulation guidance, conversion to GA was required in 7.5% of patients.…”