Thirteen adult patients with established
thalamic syndrome, resistant to prior
analgesic and other
therapy, were treated with
intravenous infusions of the
opiate antagonist,
naloxone. A total of twenty treatments were administered with doses of
naloxone varying from 4.0-8.0 mgs. Seven patients exhibited beneficial effects with the duration of the resultant
pain relief ranging from four days to two and a half years. In these patients,
pain and hyperpathia were completely obtunded in six out of seven and partially in one. Side effects of
therapy were minimal and of short duration being mainly confined to the cardiovascular system. During
therapy all patients had continuous E.C.G. monitoring. In certain ischaemic conditions of the central nervous system, endogenous
opioids possibly reduce cerebral blood flow via. inhibition of the locus coeruleus and subsequent release of
noradrenaline: hence
naloxone by inhibiting the
opioids could increase cerebral perfusion pressure. This study has shown the benefit of treating patients with cerebral ischaemic lesions with an
opioid antagonist. The rapidity of onset of
pain relief in these patients would appear to indicate a mode of action by increasing cerebral perfusion.