using an implantable pump system to deliver drugs and sample cerebrospinal fluid ( csf ) , we assessed rostral redistribution and systemic uptake after intrathecal bolus injection and steady-state infusion of morphine sulfate and the opioid peptide d-ala2-d-leu5-enkephalin ( dadl ) in two patients .
C0205753
opioid
C0014298
enkephalin