Effect of concentration and mode of intrathecal baclofen administration on soleus H-reflex in patients with muscle hypertonia.

Abstract

OBJECTIVES:

Assess spinal reflex excitability after increasing intrathecal baclofen (ITB) flow by manipulation of drug concentration and mode of administration.

METHODS:

The effect of concentration was assessed by comparing changes in H-reflex (H/M ratio) 1-6h after a 50μg ITB bolus at 50μg/ml concentration administered manually via lumbar puncture (LP, duration 1-2min, n=27) to a 50μg bolus at 500μg/ml concentration programmed through the pump and delivered via intrathecal catheter (IC, duration 10min) above simple continuous dose (25-100μg/day, n=16). The effect of mode of administration was assessed by comparing peak changes in H/M ratio after 50μg IC bolus above simple continuous dose (complex continuous mode, n=27) to simple continuous mode only (n=22) at equivalent daily doses (75-150μg/day).

RESULTS:

H/M decrease was faster and overall greater after LP than IC bolus (mean 1-h 77% vs. 63%, p=0.012; 1-6h 91% vs. 82%, p<0.001, respectively). H/M ratio also decreased significantly more with complex (91%) than simple continuous mode of administration (78%, p=0.025).

CONCLUSIONS:

Lower ITB concentration and complex continuous mode of administration lead to greater decrease in H/M ratio.

SIGNIFICANCE:

Decreased spinal reflex excitability after adjustment of drug and pump parameters to increase ITB flow may result in better clinical response.

• Authors: Dobrivoje S Stokic, Stuart A Yablon
• Journal: Clinical neurophysiology : official journal of the International Federation of Clinical Neurophysiology (Clin Neurophysiol) Vol. 123 Issue 11 Pg. 2200-4 (Nov 2012) ISSN: 1872-8952 [Electronic] Netherlands
• PMID: 22595326 (Publication Type: Clinical Trial, Comparative Study, Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2012 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Chemical References

• Muscle Relaxants, Central
• Baclofen

Topics

• Adult
• Baclofen (administration & dosage, pharmacology, therapeutic use)
• Dose-Response Relationship, Drug
• Female
• H-Reflex (drug effects, physiology)
• Humans
• Infusion Pumps
• Infusions, Spinal
• Injections, Spinal
• Male
• Middle Aged
• Muscle Hypertonia (drug therapy, physiopathology)
• Muscle Relaxants, Central (administration & dosage, pharmacology, therapeutic use)
• Muscle, Skeletal (innervation)
• Prospective Studies
• Treatment Outcome