Abstracts

RATIONALE: With advances in medicine and technology, older individuals are living into their 80's, 90's, and beyond. The elderly comprise the fastest growing segment of the population in the US. The incidence of unprovoked seizures is highest in this age group and is estimated to be 150/100,000. Treatment is complicated by the normal physiological changes of aging, comorbid diseases, and polypharmacy. METHODS: Eighteen VAMC's are participating in a cooperative study designed to evaluate the efficacy and tolerability of gabapentin (GPN), lamotrigine (LTG), and carbamazepine (CBZ) in the treatment of new onset seizures in patients ? 60 years old. Patients are randomized to GBP, LTG, or CBZ with target daily doses of 1500 mg, 150 mg, and 600 mg, respectively. Doses are reduced if adverse effects (AE) occur and increased to achieve seizure control. Primary outcome measure is retention at 52 wks. RESULTS: Presently, 333 patients have been enrolled. Mean age is 72.7 and 94.2% are males. EEG results were normal in 31.3%, epileptiform in 38.7%, focal slowing in 40.1%, and generalized slowing in 15.6%. CT/MRI findings were normal 18%, CVA 43.6%, small vessel disease 40.1%, diffuse atrophy 35%, and encephalomalacia 9.1%. Primary etiology was CVA 39.3%, unknown 32.6%, head trauma 7.4%, arteriosclerosis 7%. Seizure types are 38.3% CPS, 27.1% GTC, 14.3% SPS, and 20.3% mixed. Systemic SE reported were weight gain 24.2%, GI problems 15.5%, and weight loss 8.7%. Neurotoxicities consisted of sedation 25.9%, dizziness 14.7%, and gait disturbances 13.2%. Of those who could have completed 52 wks, 47.8% completed the trial. Reasons for termination are AE 19.4%, voluntary withdrawal 10%, death 7.2%, and uncontrolled seizures 3.3%. Concurrent disease are common and include HBP 64.4%, CVA 52.7%, cardiac disease 48.8%, diabetes 26.6%, and history of cancer 22.5%. Mean blood levels at 12 wks were GPN 8.9, LTG 3.27, and CBZ 6.47 ?g/ml. CONCLUSIONS: Older patients with new onset seizures are more likely to have AE at introduction of antiepileptic drug(AED) but will likely be controlled if AED therapy is tolerated. Vascular disease is an important problem and contributes to etiology in the majority of cases.