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Plasma digoxin concentrations and digoxin toxicity in hospital patients.

1971; BMJ; Volume: 33; Issue: 4 Linguagem: Inglês

10.1136/hrt.33.4.540

1468-201X

D.C. Evered, C.W. Chapman,

Potassium and Related Disorders

Studies were made on io8 subjects on routine oral maintenance digoxin therapy.Twenty-two were found to have eidene of digoxin toxicity.The range of plasma digoxin concentrations in these subjects is recorded (1.38 SD+oO77 ng/ml).The subjects with evidence of toxicity are shown to have significantly higher plasma digoxin concentrations (3.36 SD I2o ng/ml) though there is some overlap with the non-toxic group.The subjects with toxicity are shown to be sub- stantially older and to have a much higher incidence of raised blood urea.The implications of these observations are discussed.Recent advances in knowledge of the chemis- try (Henderson, I969) and pharmacology (Dimond, I957; Fisch and Surawicz, I969) of the cardiac glycosides have been considerable.These advances in association with a number of careful clinical studies (reviewed by Sura- wicz and Mortelmans, I969 and by Chung, I969) have provided a more rational basis for therapy with digitalis, and have led to a much wider appreciation of the protean manifesta- tions of digitalis intoxication and of factors that alter individual tolerance to digitalis.Paradoxically, however, the incidence of digi- talis intoxication is reported to have increased conspicuously in recent years and is reported to be between 7 and 22 per cent among hospital inpatients (Rodensky and Wasserman, i96i, I964; Sodeman, I965).The lack of specific chemical techniques sufficiently sensitive to measure the low con- centrations of glycosides present in the blood has hampered studies of these compounds.Lowenstein (I965) and Lowenstein and Cor- ril (I966) have developed an assay for cardiac glycosides based on the inhibition of 86Rb uptake.Using this technique, Grahame-Smith and Everest (I969) and Binnion et al. (I969) have indicated that plasma digoxin assay may make better control of digoxin therapy possible.A rapid, sensitive, and precise radio- immunoassay for digoxin has recently been