PLASMA CONCENTRATION OF MORPHINE AFTER I.M., EXTRADURAL AND INTRATHECAL ADMINISTRATION

Seventeen patients received morphine 0.2 mgkg-1 in a 10% dextrose solution i.m. (n = 5), extradurally (n = 6) and intrathecally (n = 6) for pain after operation. Morphine was measured in plasma by radioimmunoassay. Plasma immunoreactive morphine concentration was significantly less after intrathecal administration than after intrathecal administration than after i jn. and extradural administration(P