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April 9, 1973

Biologic Availability of Digoxin Tablets

Author Affiliations

Bureau of Drugs Food and Drug Administration Rockville, Md

JAMA. 1973;224(2):243. doi:10.1001/jama.1973.03220150051015

One year ago, Lindenbaum and his colleagues1 published the results of an investigation of the bioavailability of three different brands of digoxin tablets, including two different lots of one brand. While his data indicated that the blood levels varied widely, a follow-up investigation by the Food and Drug Administration (FDA) revealed that the brand giving the lowest blood level was substantially out of compliance with the United States Pharmacopeia specifications, ie, its potency was significantly outside the 92% to 108% range. At that time, sufficient tablets of the other brand that gave low blood levels could not be found for analysis. On this basis, it was the FDA's view that the problem identified by Lindenbaum et al was one of potency rather than bioavailability. In the interim, the FDA has become aware of additional studies2-5 (one of which appears in this issue on p 199) suggesting that, along