抄録
There are some cases that half life of digoxin is prolonged in elderly patients (elder than 60 years old), although serum creatinine (Scr) and serum urea nitrogen (SUN) levels are within normal range [Scr (<1.2) and SUN (<20)].The half life of digoxin in patients over 60 years old (71.6±23.2hr, n=8) was significantly longer than those in other patients (47.4±18.9hr, n=16) (p<0.05) in comparing among patients within normal Scr range.Among the elder age group, the half life in normal Scr group was 71.6±23.2hr (n=8), whereas that in abnormal Scr group tended to be prolonged to 84.4±41.8hr (n=27).In four cases where Scr is 0.3, 0.9, 1.1 and 1.4 mg/dl, the half life of digoxin calculated based on creatinine clearance that was estimated by urinary creatinine, urine volume and body surface area (2.88±0.42 day) was significantly shorter than that obtained from the serum digoxin concentrations measured at two points or more (3.65±0.37 day) (p<0.01).
These findings suggest that it is desirable to control the serum digoxin by measuring its level routinely for a better digoxin therapy in the elderly patients, since the index of elimination rate constant or the half life calculated by Scr and/or SUN might be less reliable and utilization of CLcr might be also less suitable in some cases.
