The mechanism of the recently reported interaction between digoxin and quinidine was investigated.
We found a statistically significant decrease in renal clearance of digoxin after adding quinidine to the treatment regime. In 4 patients the digoxin/creatinine renal clearance ratio during quinidine treatment (0.74±0.23, mean ±S.D.) differed significantly (P<0.01) from the ratio after quinidine therapy (1.11±0.20, mean ±S.D.). The ratio was 0.85±0.23 (mean ±S.D.) in 15 patients receiving simultaneous quinidine therapy and 1.22± 0.31 (mean ±S.D.) in 44 patients without quinidine therapy. This difference was significant (P<0.01).
Quinidine did not influencein vitro the distribution of digoxin between plasma and erythrocytes.
The elevation of the serum digoxin level during quinidine therapy can be explained partly by a decrease of the renal digoxin clearance. Our results, however, do not exclude that other mechanisms may also be involved.
Digoxin Quinidine Digoxin Concentration Serum Digoxin Concentration Clearance Ratio
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Huffman, D. H., C. V. Manion andD. L. Azarnoff (1975) Intersubject variation of digoxin in normal volunteers,J. Pharm. Sci. 64, 433.CrossRefPubMedGoogle Scholar
Iisalo, E., andI. Ruikka (1974) Serum levels and renal excretion of digoxin in the elderly. A comparison between three different preparations,Acta Med. Scand. 196, 59.CrossRefPubMedGoogle Scholar
Leahey, E. B., J. A. Reiffel, R. E. Drusin, R. H. Heisenbuttel, W. P. Lovejoy andJ. Th. Bigger (1978) Interaction between quinidine and digoxin,J. Am. Med. Assoc. 240, 533.CrossRefGoogle Scholar
Nyberg, L., K. E. Andersson andå. Bertler (1974) Bioavailability of digoxin from tablets. Radioimmunoassay and disposition pharmacokinetics of digoxin after intravenous administration,Acta Pharm. Suecica 11, 459.Google Scholar
Reuning, R. H., R. A. Sams andR. E. Notari (1973) Role of pharmacokinetics in drug dosage adjustment. Pharmacologic effect, kinetics and apparent volume of distribution of digoxin,J. Clin Pharmacol. 13, 127.Google Scholar