Assessment of epileptogenic potential: experimental, clinical and epidemiological approaches

Effect of acute and chronic tianeptine on the action of classical antiepileptics in the mouse maximal electroshock model

BACKGROUND

The aim of the study was to analyze the influence of acute and chronic treatment with tianeptine, an antidepressant selectively accelerating presynaptic serotonin reuptake, on the protective activity of classical antiepileptic drugs in the maximal electroshock test in mice.

METHODS

Electroconvulsions were produced by means of an alternating current (50 Hz, 25 mA, 0.2 s) delivered via ear-clip electrodes. Motor impairment and long-term memory deficits in animals were quantified in the chimney test and in the passive-avoidance task, respectively. Brain concentrations of antiepileptic drugs were measured by fluorescence polarization immunoassay.

RESULTS

Acute and chronic treatment with tianeptine (25-50 mg/kg) did not affect the electroconvulsive threshold. Furthermore, tianeptine applied in both acute and chronic protocols enhanced the anticonvulsant action of valproate and carbamazepine, but not that of phenytoin. Neither acute nor chronic tianeptine changed the brain concentrations of valproate, carbamazepine or phenytoin. On the other hand, both single and chronic administration of tianeptine diminished the brain concentration of phenobarbital. In spite of this pharmacokinetic interaction, the antidepressant enhanced the antielectroshock action of phenobarbital. In terms of adverse effects, acute/chronic tianeptine (50 mg/kg) and its combinations with classic antiepileptic drugs did not impair motor performance or long-term memory in mice.

CONCLUSION

The obtained results justify the conclusion that tianeptine may be beneficial in the treatment of depressive disorders in the course of epilepsy.

Acute and chronic treatment with mianserin differentially affects the anticonvulsant activity of conventional antiepileptic drugs in the mouse maximal electroshock model

RATIONALE

Epilepsy often coexists with depression. Therefore, the probability of simultaneous treatment with antiepileptics and antidepressants and the possibility of interactions between them are relatively high.

OBJECTIVE

The effects of acute and chronic administration of mianserin on the protective activity of valproate (VPA), carbamazepine, phenytoin, and phenobarbital were evaluated in the maximal electroshock in mice.

MATERIALS AND METHODS

Animals were subjected to electroconvulsions. Undesired effects were evaluated in the chimney test (motor impairment) and passive-avoidance task (memory deficit). Brain concentrations of antiepileptic drugs were assessed by immunofluorescence.

RESULTS

When given acutely, mianserin (at doses greater than or equal to 20 mg/kg) significantly raised the electroconvulsive threshold. The antidepressant, at the subanticonvulsant doses, enhanced the anticonvulsant action of carbamazepine, phenytoin, and VPA. Mianserin administered chronically at 30 mg/kg significantly decreased the electroconvulsive threshold. In contrast to acute treatment, the antidepressant at subeffective doses diminished the anticonvulsant activity of VPA and phenytoin. Mianserin given either acutely or chronically did not affect the brain concentrations of antiepileptic drugs, so a pharmacokinetic contribution to the observed interactions is not probable. Acute and chronic treatment with mianserin and its combinations with antiepileptic drugs did not impair either motor coordination or long-term memory.

CONCLUSION

Although acute application of mianserin may potentiate the anticonvulsant action of some antiepileptics, its chronic administration can lead to the opposite effect. Therefore, as far as the presented results can be transferred to clinical conditions, the antidepressant therapy with mianserin should be limited or even avoided in epileptic patients.

Epilepsy, depression and antidepressant drugs

Apart from constituting an important management problem, depression coexisting with epilepsy is also an interesting psychiatric phenomenon, with multiple interacting biological, psychological and social factors involved in its causation. New research approaches to the study of epilepsy and depression, including neuroimaging, neurochemical and neuroendocrine techniques, and the arrival of new classes of antidepressants in recent years, suggest it is timely to reconsider this topic. We review current knowledge of the prevalence and causes of interictal depression in epilepsy, focussing mainly on neurobiological factors, and give an overview of recent concepts concerning the management of depression. We also discuss pharmacological treatment of depression in epilepsy, focussing on the association between antidepressants and seizures, and drug interactions.

Prescription-event monitoring of 10,401 patients treated with fluvoxamine

Prescription-event monitoring (PEM) is one of two national systems of drug safety monitoring practised in Britain. The objective of this PEM study was to assess the safety of fluvoxamine and to monitor the occurrence of untoward and other events during treatment. A total of 10,401 patients treated with the drug in general practices throughout England were studied and data were analysed in the Drug Safety Research Unit, Southampton. The main outcome measures were the overall incidence of events per 1000 patients; the incidence during the first month of treatment; the mean incidence for months 2-6 of treatment; and the ratio of these rates as a signal that an event could be drug related. The most commonly reported category of events was neuropsychiatric while the most commonly reported individual events were nausea and vomiting. Fluvoxamine was shown to be a safe drug and no unexpected or previously undetected drug-related events were encountered. There was a relatively high incidence of gastro-intestinal symptoms, but other adverse reactions often encountered during treatment with tricyclic antidepressants were not frequently reported.