morphine-3-glucuronide and Subarachnoid-Hemorrhage

In animals, central nervous system inflammation increases drug accumulation in the brain partly due to a loss of central nervous system drug efflux transporter function at the blood-brain barrier. To determine whether a similar loss of active drug efflux occurs in humans after acute inflammatory brain injury.. Observational human pharmacokinetic study.. Medical-surgical-neurosurgical intensive care unit at a university-affiliated, Canadian tertiary care center.. Patients with acute inflammatory brain injury, including subarachnoid hemorrhage (n = 10), intracerebral and/or intraventricular hemorrhage (n = 4), or closed head trauma (n = 2) who received morphine intravenously after being fitted with cerebrospinal fluid ventriculostomy and peripheral arterial catheters.. We correlated the cerebrospinal fluid distribution of morphine, morphine-3-glucuronide, and morphine-6-glucuronide with the cerebrospinal fluid and plasma concentration of the proinflammatory cytokine interleukin-6 and the passive marker of blood-brain barrier permeability, albumin.. Acute brain injury produced a robust inflammatory response in the central nervous system as reflected by the elevated concentration of interleukin-6 in cerebrospinal fluid. Penetration of morphine metabolites into the central nervous system increased in proportion to the neuroinflammatory response as demonstrated by the positive correlation between cerebrospinal fluid interleukin-6 exposure and the area under the curve cerebrospinal fluid/plasma ratio for morphine-3-glucuronide (r = .49, p < .001) and morphine-6-glucuronide (r = .51, p < .001). In contrast, distribution of morphine into the brain was not linked with cerebrospinal fluid interleukin-6 exposure (r = .073, p = .54). Albumin concentrations in plasma and cerebrospinal fluid were consistently in the normal range, indicating that the physical integrity of the blood-brain barrier was likely undisturbed.. Our results suggest that central nervous system inflammation following acute brain injury may selectively inhibit the activity of specific drug efflux transporters within the blood-brain barrier. This finding may have significant implications for patients with neuroinflammatory conditions when administered centrally acting drugs normally excluded from the brain by such transporters.

Topics: Adult; Aged; Analgesics, Opioid; Blood-Brain Barrier; Brain; Cerebral Hemorrhage; Critical Care; Dose-Response Relationship, Drug; Female; Head Injuries, Closed; Humans; Interleukin-6; Male; Metabolic Clearance Rate; Middle Aged; Morphine; Morphine Derivatives; Serum Albumin; Subarachnoid Hemorrhage; Ventriculostomy

Topics: Analgesics, Opioid; ATP-Binding Cassette Transporters; Blood-Brain Barrier; Brain; Cerebral Hemorrhage; Conscious Sedation; Critical Care; Dose-Response Relationship, Drug; Head Injuries, Closed; Humans; Interleukin-6; Metabolic Clearance Rate; Morphine; Morphine Derivatives; Subarachnoid Hemorrhage