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Absorption Characteristics of Sustained‐Release 4‐Aminopyridine (Fampridine SR) in Patients with Chronic Spinal Cord Injury
Author(s) -
MD Jack L. Segal,
Hayes Keith C.,
Brunnemann Sherry R.,
Hsieh Jane T. C.,
Potter Patrick J.,
Pathak Mayank S.,
Tierney David S.,
Mason David
Publication year - 2000
Publication title -
the journal of clinical pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.92
H-Index - 116
eISSN - 1552-4604
pISSN - 0091-2700
DOI - 10.1177/00912700022008982
Subject(s) - cmax , medicine , spinal cord injury , 4 aminopyridine , anesthesia , pharmacokinetics , bioavailability , dosing , absorption (acoustics) , spinal cord , pharmacology , potassium channel , physics , psychiatry , acoustics
Fampridine SR (4‐aminopyridine) is a potassium channel‐blocking drug currently being investigated for its therapeutic efficacy in ameliorating central conduction deficits due to demyelination in patients with spinal cord injury (SCI). The present open‐label pharmacokinetic trial examined the absorption characteristics of a sustained‐release form of the drug in 25 SCI subjects with chronic in complete injuries. The overall group mean C max of 27.7 ± 6.2 ng/mL occurred at a t msx of 3.4 ± 1.4 hours. AUC 0–12 was 210.5 ± 49.5 ng/mL•h. For paraplegics, AUCt max was 76.02 ± 33.28 and for tetraplegics was significantly less at 51.25 ± 20.36 (p = 0.037). A statistically significant difference in the initial rate and extent of absorption, but not in total 4‐AP bioavailability over the 12‐hour study period, was evident between tetraplegic patients, 0.60 ± 0.23, and paraplegic patients, 0.39 ± 0.14 (p = 0.02). There was a linear correlation (p < 0.05) between the neurological level of injury and C max /AUCt max . These results confirm and extend previous observations of different rates of drug absorption among SCI patients with lesions above and below the sympathetic outflow (T 6 ) and provide evidence of the absorption characteristics of this sustained‐release form of 4‐aminopyridine, which is helpful for optimal dosing.