The relationship of serum anticholinergic activity to mental status performance in an elderly nursing home population

Abstract

Adverse drug reactions among elderly patients pose a significant clinical problem. The authors used a serum radioreceptor assay [RRA] to quantify drug-induced muscarinic blockade in 34 randomly selected nursing home residents. A random intervention group and the nonintervention control subjects were then retested 4 weeks later. The reduction of serum antimuscarinic activity (as determined by RRA) did relate to changes on several measures of cognitive function. A calculated "antimuscarinic index" lost significance with the RRA following intervention and may have overestimated the impact of a dosage reduction.