Plasma morphine concentrations and analgesic effects of lumbar extradural morphine and heroin.
Patients undergoing lumbar laminectomy were given extradural narcotic, either 5 mg morphine sulphate or 5.5 mg heroin (diamorphine hydrochloride); the extradural catheter had been positioned adjacent to the dura under direct vision. Plasma morphine concentrations measured by specific radioimmunoassay showed that peak concentrations occurred significantly earlier with heroin (4.7 +/- 0.6 min, mean +/- SEM) than with morphine (7.6 +/- 0.9 min) and that peak concentrations were significantly higher after heroin 5-10 min after extradural injection. The fraction of extradural heroin crossing the dura was estimated to be 55% of the fraction of morphine crossing the dura. Postoperative fentanyl requirements using demand analgesia were the same with extradural morphine as with extradural heroin (mean, 6.6 micrograms/hr). Clinically significant slowing of respiratory rate occurred only after extradural heroin (three patients).
D000328:Adult; D000698:Analgesia; D000767:Anesthesia, Epidural; D005260:Female; D003932:Heroin / Q000009:adverse effects; D006801:Humans; D007700:Kinetics; D007796:Laminectomy; D008297:Male; D009020:Morphine / Q000009:adverse effects / Q000097:blood*; D010149:Postoperative Pain / Q000517:prevention & control; D011863:Radioimmunoassay; D012119:Respiration / Q000187:drug effects; D013997:Time Factors; D014839:Vomiting / Q000139:chemically induced
D003932:Heroin; D009020:Morphine