[Pharmacologic modification of vigilance in the postnarcotic phase-- naloxone or physostigmine?]

The usefulness of physostigmine in reversing post-narcotic depression after general anaesthesia is well proven; so is that of naloxone, a specific opioid analgetics antagonist, in reversing neuroleptic anaesthesia effects. Morphine-like analgetics are widely used as premedication agents, too; on the other hand, physostigmine reverses opioids as well as other psychotropic and narcotic agents. For that reason, positive post-narcotic physostigmine effects could be due to its anti-opioid potency as well. In a double-blind, randomised study, physostigmine and naloxone were evaluated using a clinically based vigilance protocol, and compared with saline solution. Naloxone did not have remarkable advantages as compared with placebo, while physostigmine led to a significantly higher level of vigilance; moreover, that level was reached sooner. The positive effects of physostigmine in restoring a sufficient level of vigilance after general anaesthesia are, in respect of our findings, unrelated to its antagonism to morphine-like analgetics.