Correlation between manifestations of digoxin toxicity and serum digoxin, calcium, potassium, and magnesium concentrations and arterial pH.

Abstract

In 18 patients with gastrointestinal manifestations of digoxin toxicity the mean serum digoxin concentration (+ SEM) was 3 16 ,tg/l (± 0-25), the calcium to potassium ratio 0 31 (±0 01), and the mean arterial pH 7 406 (4-0017). In contrast 19 patients with digoxin induced automaticity had a mean serum digoxin concentration of 124 [tg/l ( 0-15; p<0001), a calcium to potassium ratio of 038 (±001; p<001), and an arterial pH of 7498 (I 0008; p <0001). Eight out of 13 patients with digoxin induced cardiotoxicity had serum concentrations of the drug within the therapeutic range (0-8-2-0 tg/l). The calcium to potassium ratio, however, was lower than in the patients with automaticity (0 31±0 02; p<0 01) and the arterial pH was 7-370 (±0 033; p<0 05). Serum magnesium concentrations were similar in all groups.In this study patients with digoxin induced gastrointestinal symptoms had high serum concentrations of the drug, whereas those with drug induced automaticity had therapeutic concentrations. This second group, however, was identified by their higher calcium to potassium ratios and higher pH values.

Digoxin: The good and the bad

“…There is a linear relationship between digoxin dose and SDC, but accurately adjusting the dose relies on blood being collected at the correct time, under stable renal function. Even when SDC is in the optimal therapeutic range (0.5-0.9 ng/mL), patients have demonstrated clinical signs of toxicity, and conversely asymptomatic patients with "toxic" SDCs have been reported (57). Thus, given the poor correlation between SDC and clinical findings, digoxin intoxication remains a clinical diagnosis.…”

Digoxin Toxicity

“…It has been widely accepted that deteriorating renal function and electrolyte abnormalities (hypokalemia, hypomagnesemia, hypercalcemia) predispose patients to digoxin toxicity. 20,21 In our study, none of these factors differed significantly (PϾ.05) among the 3 groups, although serum urea nitrogen and serum creatinine levels tended to be higher in patients with definite or possible digoxin intoxication than those without intoxication. However, serum urea nitrogen and serum creatinine are not the best predictors of renal function, and creatinine clearance would have likely been more indicative.…”

Korean Society of Heart Failure Guidelines for the Management of Heart Failure: Treatment

“…Side effects occur when digoxin is co-administered with drugs that can affect digoxin metabolism (macrolide antibiotics, itraconazole, cyclosporin, amiodarone, quinidine, etc.). 42 43 44) …”