Abstracts

Rationale: Increased seizure activity among institutionalized patients receiving care at MINCEP Epilepsy Clinic prompted an investigation of all patients with breakthrough seizures. A retrospective chart review was carried out to determine what factors may have played a role in the clinical course of these patients. Method: Caregivers notified MINCEP (5/99 to 10/99) when an institutionalized patient had a hospitalization, ER visit, or significant change in seizure frequency. A switch from Dilantin Kapseals (100 mg) to generic extended PHT sodium capsules coincided with the change in seizure control in 11 patients. Patients were switched back to brand. A retrospective chart review obtained demographics, concomitant medications, PHT dose, and bound and unbound PHT plasma concentrations. Two of the 11 patients were excluded because they had not reached steady-state on generic PHT. In the other nine patients (age range 25-49 years, 4 females and 5 males) there were no important changes in co-medications or other factors except a switch from brand to generic extended PHT sodium capsules. Mean PHT doses were the same for all three groups: 324?80 mg/day. Total PHT levels were: brand, 17.8?5.3 (n=20)*; generic, 12.8?3.0 (n=19)*; back to brand 17.0?4.5 (n=9). Free levels: brand 2.3?0.5 (n=19)*; generic, 1.6?0.3 (n=17)*; back to brand 2.3?0.5 (n=9). The differences between brand and generic were statictically significant (p?0.05); but brand back to brand was not. *multiple samples on many patients Conclusion: Substitution of generic for the brand product was associated with a decrease of approximately 30% total and unbound PHT. PHT concentrations on brand before and after switching were the same. Physicians and pharmacists need to be alerted when switching from brand to generic PHT. Research was supported in part by NIH-NINDS Grant P50 16308