Lack of Carbamazepine Toxicity in Frail Nursing Home Patients: A Controlled Study

OBJECTIVE: To assess the effects of carbamazepine and placebo on measures of toxicity in frail nursing home patients. DESIGN: A nonrandomized, double-blind, placebo-controlled crossover study. SETTING: Two nursing homes in Rochester, New York. PARTICIPANTS: Twenty-five subjects (mean age 84.5 years) with dementia. INTERVENTION: Carbamazepine and placebo during two 5-week periods separated by a 2-week washout. The modal dose for each patient was 300 mg/day. MEASUREMENTS: Adverse experiences, comorbid events, and physical signs and symptoms were assessed continuously, and laboratory data were examined at the beginning and end of each treatment period. RESULTS: One subject died with a pneumonia (and elevated white blood cell count), and one subject developed probable carbamazepine-induced tics. There was a minimal drop in hematocrit and a slight elevation of liver enzymes, none of which was clinically significant. There was otherwise no excess of adversity or comorbid events on carbamazepine versus placebo, and there was no change in electrolytes or other laboratory measures. CONCLUSION: The findings indicate that carbamazepine in this dose range was well tolerated for the 5-week treatment period in this frail sample. These data supplement the literature regarding carbamazepine toxicity, which is devoid of controlled studies in older subjects.