Zonisamide and neuropathic pain

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Rev Neurol. 2007 Oct 1-15;45(7):429-32.

Zonisamide and neuropathic pain

López-Trigo J, Ortiz-Sánchez P, Blanco-Hernández T.

Servicio de Neurología, Hospital General Universitario de Valencia,

46014 Valencia, Spain.

INTRODUCTION: In neuropathic pain, as occurs in epilepsy, researchers

are striving to find a drug capable of inhibiting the pain-generating

ectopic discharges that are produced as a result of neuronal

hyperexcitability. This is mediated by ionic exchanges across the

channels of the synaptic membrane. This is why the drugs that act on

the different types of channels involved in this transmission can

regulate neuronal hyperexcitability and therefore have an effect on

the pain.

DEVELOPMENT: In recent years researchers have gained a deeper

understanding of the mechanisms of action of antiepileptic drugs and,

since the discovery of their action on one or several synaptic

channels, the use of these agents to treat neuropathic pain has

become increasingly common. Patients suffering from central pain are

also beginning to benefit from the administration of these drugs,

especially agents that have proved to be capable of acting with

several mechanisms of action and on several channels at the same

time. In addition, fewer and less severe side effects are produced,

something that is fundamental if we bear in mind the characteristics

of patients with central pain, most of whom are adults and elderly.

This, together with the fact that there are fewer interactions with

other drugs, has led to the new antiepileptic drugs' becoming the

preferred medication for this pathology today.

CONCLUSIONS: Zonisamide acts on several types of channels and it is

known to have four different mechanisms of action, which means it can

be effective in treating these patients, although further studies are

required (above all randomised double-blind trials) in order to

really evaluate the usefulness of these drugs in the treatment of

neuropathic pain.