Antiepileptic age, polytherapy linked to more adverse effects.
"The adverse effect profiles of antiepileptic drugs are often determining factors in drug selection, and yet adverse effects may be overlooked in everyday clinical practice," Joyce A. Cramer wrote in a poster presented at the annual congress of the European Federation of Neurological Societies.
Ms. Cramer, a research scientist at Yale University, New Haven, Conn., conducted a population surveillance study in six European countries to evaluate the adverse effects of both newer and older antiepileptic drugs (AEDs).
The study population comprised 1,019 patients (mean age, 31 years) who had been on a stable dosing regimen for a median of 13 months. Of those, 57% were on monotherapy, and 43% were on polytherapy. Most of the patients (71%) were taking at least one older AED (carbamazepine, clobazam, clonazepam, phenobarbital, phenytoin, or valproate). The rest were taking at least one newer AED (gabapentin, lamotrigine, levetiracetam, oxcarbazepine, pregabalin, tiagabine, topira-mate, and zonisamide).
At least one adverse effect occurred in 68% of the patients. Newer AEDs were associated with fewer reports of adverse effects than were older drugs (61% vs. 71%, respectively), and monotherapy was associated with fewer reports of adverse effects than was polytherapy (66% vs. 71%).
Neurologic adverse effects were more common in those taking older AEDs than in those taking newer AEDs (60% vs. 54%, respectively), as were systemic adverse effects (42% vs. 33%).
Neurologic adverse effects were also more common in patients on polytherapy than in those on monotherapy (64% vs. 53%), although the percentage of patients reporting systemic adverse effects was equal in these two groups (40%).
Adverse effects that were significantly more common in those taking the older drugs, compared with newer ones, were cognitive slowing (30% vs. 22%), sedation (30% vs. 23%), and tremor (18% vs. 10%).
Adverse effects that were significantly more common in those taking polytherapy, compared with monotherapy, were cognitive slowing (36% vs. 22%), psychological problems (31% vs. 22%), tremor (21% vs. 11%), and gait disturbances (12% vs. 7%).
A logistic regression analysis concluded that patients on newer AEDs were 36% less likely than were those on the older drugs to report at least one adverse effect. Treatment modifications were 52% more likely in those reporting adverse effects.
The study was sponsored by UCB Pharma Inc., which makes levetiracetam. Ms. Cramer is a consultant for the company.
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|Publication:||Clinical Psychiatry News|
|Date:||Jan 1, 2009|
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