Neuronal blockade with morphine. A hypothesis

A patient with an apical lung tumour invading the brachial plexus (Pancoast's tumour) suffered from unbearable pain unmodified 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 effect, an hypothesis which ought to be subjected to controlled trials.