Psychostimulants and epilepsy

PURPOSE

The aim of this article is to review the literature on the effects of psychostimulants in epileptic subjects in order to reach a consensus statement regarding the use or abuse of these substances.

METHODS

Psychostimulant substances have been considered the drugs that share the ability to produce excitation of the CNS leading to convulsions. The stimulation may be at cortical, brainstem, or spinal levels. In this article, the following cortical stimulants are analyzed and discussed: cocaine, amphetamine and related agents, caffeine, cannabinoids, and psychedelic drugs. This review is based on research done using pharmacological textbooks and Medline.

RESULTS

The use of cocaine is associated with the occurrence of seizures. The reported frequency varies from 1% to 40% of addicted subjects, based on the typology of the considered study. Amphetamines and related drugs rarely induce epileptic seizures at therapeutic doses, but seizures may occur after the first dosing. Caffeine at high doses may induce epileptic seizures because of its adenosine receptor-antagonizing properties. Marijuana, at variance with other psychostimulants, owing to its serotonin-mediated anticonvulsant action, could have a medical use for the treatment of epilepsy. Psychedelic compounds rarely induce epileptic seizures, but the most common clinical CNS complication after ingestion of ecstasy is the occurrence of seizures.

CONCLUSIONS

The use of psychostimulants, except for marijuana, can induce single or multiple seizures in healthy subjects.

Allopurinol as add-on therapy in refractory epilepsy: a double-blind placebo-controlled randomized study

The antiepileptic effect of allopurinol was assessed in a double-blind, randomized, placebo-controlled, cross-over trial in 84 patients with epileptic seizures refractory to standard antiepileptic drugs (AEDs). During a retrospective baseline period, patients experienced at least four seizures of any type per month. The effects of allopurinol and matching placebo were examined for 4-month periods. Allopurinol dosage was 150 mg daily for children weighing < 20 kg and 300 mg daily for other patients. Efficacy analysis based on the Wilcoxon rank-sum test was conducted for the 80 patients who completed the study. No significant period effect or treatment-period interaction was noted. Allopurinol significantly reduced total seizures (p = 0.005), and secondarily generalized seizures (p = 0.0015). Median seizure reduction for total seizures was 10.5 and 27.9% for secondarily generalized seizures. Subjective preferences by clinicians evaluated blindly significantly favored allopurinol. No significant change occurred in the plasma concentration of concomitant AEDs between treatment periods, but serum urate decreased by 32% during allopurinol treatment. No clinically relevant side effects or changes in routine laboratory clinical chemistry or hematology were ascribed to allopurinol.

Oxiracetam in the treatment of primary degenerative and multi-infarct dementia: a double-blind, placebo-controlled study

A multicentre, double-blind, between-patient study was carried out to evaluate the efficacy and tolerability of oxiracetam (800-mg tablets), in comparison with placebo, each given twice daily for 12 weeks to patients suffering from primary degenerative, multi-infarct or mixed forms of dementia. Efficacy was assessed by the Inventory of Psychic and Somatic Complaints in the Elderly (IPSC-E), administered at entry and after 4, 8 and 12 weeks of treatment, and by the Blessed Dementia Scale and the Newcastle Memory, Information and Concentration Scale (NMICS), administered at the beginning and at the end of the study. Three hundred and seven patients were enrolled, 18 of whom were excluded from the analysis because of violation of the protocol. Two hundred and eighty-nine patients were analyzed (145 m, 144 f, mean age 73 years) and 272 completed the study; 3 patients in each treatment group were withdrawn because of poor tolerability, 10 because of poor compliance and 1 patient because of the occurrence of a cerebral stroke. A significantly (p less than 0.01) different effect, in favor of oxiracetam, was observed in the three main efficacy criteria (i.e. IPSC-E, Blessed Dementia Scale and NMIC total scores), and confirmed by descriptive analyses carried out on some subitems of the scales used. Thirty-one patients on oxiracetam and 27 on placebo complained of a total of 35 and 32 minor unwanted effects, respectively. No clinically or statistically significant changes were observed on routine laboratory examinations.