To the Editor:
The case report by Sun  was quite interesting, but the described features were not necessarily a withdrawal syndrome after a single dose of epidural morphine. Naloxone has visible consequences when the endogenous opioid system has been activated, as in certain forms of stress . Labor and parturition are moments of extreme physical stress with significantly increased levels of beta-endorphin . The antagonistic action of naloxone on the endogenous opioid system probably contributed to the clinical features in this patient.
Moreover, the features described do not fit into the typical withdrawal features. No dysphoria, yawning, or upset stomach was noted . Rather, the clinical features described may be explained on the basis of the known metabolic, analeptic, and hemodynamic effects of naloxone . Side effects have been described in healthy young women with doses as small as 100 [micro sign]g IV . The time course of the reported clinical effects is explained by the plasma half-life and duration of effects of naloxone . Naloxone is not a benign medication, and careful titration of 20-40 [micro sign]g  or a prophylactic infusion of 5 [micro sign]g [center dot] kg-1 [center dot] h-1 is recommended.
Ike I. Eriator, MD
Department of Anesthesiology; University of Mississippi School of Medicine; Jackson, MS 39216
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