—Drs Fuchs and Wenger explain that the unannounced change in bioavailability of digoxin took place in the United Kingdom but not in this country. My source of information was an article by an English pharmacologist1 who indicated that the medical profession was unaware of the change in potency. I did not know that the manufacturing process of the same drug by the same company is different here and in the United Kingdom.
I stand corrected and gladly withdraw the remarks pertaining to the precise dosage schedule. However, this fact in no way alters the sense of the discussion dealing with digitalis dosage, inasmuch as the comments on change in bioavailability were used merely as an illustration and not as a part of the chain of logic.
The relationship suggested in the letter between bioavailability and long-term efficacy of digoxin has no basis in fact. The article quoted by the
Selzer A. The Manufacture of Digitalis-Reply. Arch Intern Med. 1982;142(1):201. doi:10.1001/archinte.1982.00340140203041