Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Comparative Study
. 2000 Mar;92(3):739-53.
doi: 10.1097/00000542-200003000-00018.

Comparative spinal distribution and clearance kinetics of intrathecally administered morphine, fentanyl, alfentanil, and sufentanil

Affiliations
Comparative Study

Comparative spinal distribution and clearance kinetics of intrathecally administered morphine, fentanyl, alfentanil, and sufentanil

W C Ummenhofer et al. Anesthesiology. 2000 Mar.

Abstract

Background: Despite widespread use, little is known about the comparative pharmacokinetics of intrathecally administered opioids. The present study was designed to characterize the rate and extent of opioid distribution within cerebrospinal fluid, spinal cord, epidural space, and systemic circulation after intrathecal injection.

Methods: Equal doses of morphine and alfentanil, fentanyl, or sufentanil were administered intrathecally (L3) to anesthetized pigs. Microdialysis probes were used to sample cerebrospinal fluid at L2, T11, T7, T3, and the epidural space at L2 every 5-10 min for 4 h. At the end of the experiment, spinal cord and epidural fat tissue were sampled, and each probe's recovery was determined in vitro. Using SAAM II pharmacokinetic modeling software (SAAM Institute, University of Washington, Seattle, WA), the data were fit to a 16-compartment model that was divided into four spinal levels, each of which consisted of a caternary arrangement of four compartments representing the spinal cord, cerebrospinal fluid, epidural space, and epidural fat.

Results: Model simulations revealed that the integral exposure (area under the curve divided by dose) of the spinal cord (i.e., effect compartment) to the opioids was highest for morphine because of its low spinal cord distribution volume and slow clearance into plasma The integral exposure of the spinal cord to the other opioids was relatively low, but for different reasons: alfentanil has a high clearance from spinal cord into plasma, fentanyl distributes rapidly into the epidural space and fat, and sufentanil has a high spinal cord volume of distribution.

Conclusions: The four opioids studied demonstrate markedly different pharmacokinetic behavior, which correlates well with their pharmacodynamic behavior.

PubMed Disclaimer

Comment in

  • Location, location, location.
    Shafer SL, Eisenach JC. Shafer SL, et al. Anesthesiology. 2000 Mar;92(3):641-3. doi: 10.1097/00000542-200003000-00005. Anesthesiology. 2000. PMID: 10719940 No abstract available.

Similar articles

Cited by

Publication types

MeSH terms

LinkOut - more resources