Frequency of drug combinations between enzyme-inducing first-generation antiepileptic drugs and inducible drugs in patients with epilepsy.

OBJECTIVE

The objective of the study was to systematically assess, through the analysis of administrative data, the frequency of combinations of first-generation enzyme-inducing (EI) antiepileptic drugs (AEDs) with drugs frequently prescribed in patients with epilepsy whose metabolism is induced by EIAEDs.

METHODS

From the population of Tuscany (a region in Italy of about 3,750,000 habitants), patients who had been treated with at least one first-generation EIAEDs (carbamazepine, phenytoin, phenobarbital, and primidone) and had received prescriptions of an inducible non-AED (NON-AED) included in a prespecified list of 103 inducible drugs were identified.

RESULTS

At the index date, 9221 patients with epilepsy were treated with at least one traditional EIAED, and there were 2538 drug combinations between EIAEDs and NON-AEDs, which may result in potentially serious clinical consequences, and 3317 combinations with NON-AEDs that have their metabolism consistently increased.

CONCLUSIONS

Patients with epilepsy treated with traditional EIAEDs are at a very high risk of drug interactions.