DIGOXIN - CONTINUOUS OR DISCONTINUOUS TREATMENT

In our country, patients with congestive heart failure who are treated chronically with digoxin are usually advised by their physicians to s top taking the medication two days a week. This is probably aimed at d ecreasing digitalis toxicity. Based on digoxin pharmacokinetics we ass umed that the drug plasmatic level should diminish by 40 to 50%, below the therapeutic concentration of 0.8 to 2 mu g/l, after two days of s uspension. The objectives of this study were: a) to analize the reduct ion of the plasmatic concentration of digoxin after a two day interrup tion of treatment, b) to compare the plasmatic levels of the drug betw een patients who receive continuous and discontinuous treatment. A pro spective, randomized and simple blind trial was designed. A total of 3 6 patients with congestive heart failure and systolic dysfunction with atrial fibrillation or sinus rythm were included. Group 1 (19 patient s) received continuous treatment and Group 2 (17 patients) took the dr ug from Monday to Friday. In the continuous treatment group there was no significant difference between the Monday (1.06 +/- 0.55 mu g/l) an d the Friday (1.1 +/- 0.57 mu g/l) digoxin concentrations. In the disc ontinuous treatment group the Monday digoxin concentration (0.611 +/- 0.396 mu g/l) was lower than the Friday one (1.04 +/- 0.58 mu g/l), Th e difference was statistically significant with a p = 0.000002, In con clusion, the two days a week suspension schedule reduces the plasmatic concentration of digoxin to subtherapeutic levels while the continuou s regime maintains stable concentrations within the therapeutic range. Adjusting the dose to the creatinin clearance, average concentrations of 1 mu g/l are obtained. These results suggest that digitalis intoxi cation could be prevented by adjusting the dose according to renal fun ction rather than interrupting the treatment as it is usually done in our country.