Concentraciones plasmáticas de digoxina en cuatro esquemas terapéuticos de uso común en la práctica clínica / Digoxin plasma levels in patients usign four common therapeutic schedules
Four groups of patients were studied. Group I corresponded to 56 patients taking digoxin 0.25 mg/day, from Monday to Friday. Group II corresponded to 30 patients taking digoxin 0.25 mg/day, from Monday to Saturday. Group III corresponded to 53 patients taking digoxin 0.25 mg/day continuosly. Group IV corresponded to 36 patients taking digoxin 0.125 mg/day continuosly. Plasmadigoxin levels were measured in two consecutive Mondays before taking the daily dose of the drug. Serumcreatinine was also measured and creatinine clearance was calculated. The therapeuticplasma concentration range was set between 0.5 and 2 ng/ml.
Results:
Mean plasmadigoxin levels were 1.15±0.8 ng/ml in group I, 1.4±0.55 ng/ml in group II, 1.68±0.7 ng/ml in group III and 1.14±0.43 ng/ml in group IV. 93 percent of patients in group I, 80 percent of patients in group I, 80 percent of patients in group II, 75 percent of patients in group III and 94 percent of patients in group IV had therapeuticdigoxin levels. A low creatinine clearance, an age over 65 and interactions with other drugs were risk factors associated with supratherapeutic levels, mostly seen in group II and group III with 20 percent and 24 percent respectively.