Effects of topiramate on peripheral nerve excitability.
OBJECTIVE
Antiepileptic drugs are generally used to control the cortical hyperexcitable states. But some of them are also effective on the peripheral nervous system, so they may be used in some states like neuropathic pain. Several recent reports suggest the possible effects of antiepileptic drugs on peripheral nerve excitability. Strength duration time properties gives an indirect idea about the persistent, paranodal sodium (Na) channels and may indirectly reflect the peripheral nerve excitability. Topiramate suppresses the cortical hyperexcitability, but previous studies could not prove a significant effect of topiramate on peripheral nerves. The aim of this study is to investigate the probable nerve excitability changes caused by topiramate.


METHODS
Forty migraine patients and 40 controls were included in the study. Median motor and sensory conduction parameters were recorded. Strength duration properties were also recorded from abductor pollicis longus muscle, with the stimulation of median nerve. The electrophysiological studies were repeated 4 weeks after the initiation of topiramate in the treatment group.


RESULTS
Nerve conduction parameters were not significantly affected by 4-week topiramate treatment. But the strength duration time constant decreased significantly, reflecting a reduction in the excitability. This decrement seemed to be more obvious in those in whom topiramate was also clinically useful.


CONCLUSIONS
The method used demonstrated a probable effect of topiramate on the peripheral nerve excitability.
Department of Neurology, Pamukkale University Medical Faculty, Denizli, Turkey. drcagdaserdogan@gmail.com
Cağdaş
C
Erdoğan
Mehmet
M
Yücel
Hakan
H
Akgün
Tayfun
T
Kaşkç
Vedat
V
Semai Bek
Zeki
Z
Gökçil
D000200:Action Potentials / Q000187:drug effects; D000328:Adult; D000927:Anticonvulsants / Q000494:pharmacology*; D004576:Electromyography / Q000187:drug effects; D004827:Epilepsy / Q000188:drug therapy; D019054:Evoked Potentials, Motor / Q000187:drug effects*; D005073:Evoked Potentials, Somatosensory / Q000187:drug effects*; D005260:Female; D005632:Fructose / Q000031:analogs & derivatives* / Q000494:pharmacology; D006801:Humans; D009431:Neural Conduction / Q000187:drug effects*; D010525:Peripheral Nerves / Q000187:drug effects* / Q000502:physiology; D000077236:Topiramate; D014953:Wrist / Q000294:innervation
D000927:Anticonvulsants; D000077236:Topiramate; D005632:Fructose