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Quinidex Extentabs


Digitalis Glycosides/Quinidine

This information is generalized and not intended as specific medical advice. Consult your healthcare professional before taking or discontinuing any drug or commencing any course of treatment.

Medical warning:

Serious. These medicines may interact and cause very harmful effects. Contact your healthcare professional (e.g. doctor or pharmacist) for more information.

How the interaction occurs:

Quinidine may increase the blood level of the digitalis glycoside (e.g. digoxin).

What might happen:

Your blood levels of digoxin may increase causing loss of appetite, nausea, vomiting, diarrhea, headache, weakness, blurred vision, confusion, and a fast or slow or irregular heartbeat.

What you should do about this interaction:

Let your healthcare professionals (e.g. doctor or pharmacist) know that you are taking these medicines together. Notify your doctor if you are experiencing nausea, vomiting, diarrhea, loss of appetite, unusual fatigue, fast or slow or irregular heartbeat, or vision changes (e.g. blurred vision or yellow/green halos around objects). You may need to have your blood level of digoxin checked, and your dose may need to be adjusted. You may be more likely to experience effects from this interaction if you have liver problems or are elderly.Your healthcare professionals (e.g. doctor or pharmacist) may already be aware of this interaction and may be monitoring you for it. Do not start, stop, or change the dosage of any medicine before checking with them first.


1.Wandell M, Powell JR, Hager WD, Fenster PE, Graves PE, Conrad KA, Goldman S. Effect of quinine on digoxin kinetics. Clin Pharmacol Ther 1980 Oct; 28(4):425-30.

2.Mordel A, Halkin H, Zulty L, Almog S, Ezra D. Quinidine enhances digitalis toxicity at therapeutic serum digoxin levels. Clin Pharmacol Ther 1993 Apr;53(4):457-62.

3.Igel S, Drescher S, Murdter T, Hofmann U, Heinkele G, Tegude H, Glaeser H, Brenner SS, Somogyi AA, Omari T, Schafer C, Eichelbaum M, Fromm MF. Increased absorption of digoxin from the human jejunum due to inhibition of intestinal transporter-mediated efflux. Clin Pharmacokinet 2007; 46(9):777-85.

4.Aronson JK, Carver JG. Interaction of digoxin with quinine. Lancet 1981 Jun 27;1(8235):1418.

5.Schenck-Gustafsson K, Jogestrand T, Brodin LA, Nordlander R, Dahlqvist R. Cardiac effects of treatment with quinidine and digoxin, alone and in combination. Am J Cardiol 1983 Mar 1;51(5):777-82.

6.Doering W. Effect of coadministration of verapamil and quinidine on serum digoxin concentration. Eur J Clin Pharmacol 1983;25(4):517-21.

7.Bussey HI. Update on the influence of quinidine and other agents on digitalis glycosides. Am Heart J 1984 Jan;107(1):143-6.

8.Jogestrand T, Schenck-Gustafsson K, Nordlander R, Dahlqvist R. Quinidine-induced changes in serum and skeletal muscle digoxin concentration; evidence of saturable binding of digoxin to skeletal muscle. Eur J Clin Pharmacol 1984;27(5):571-5.

9.Das G, Barr CE, Carlson J. Reduction of digoxin effect during the digoxin-quinidine interaction. Clin Pharmacol Ther 1984 Mar;35(3):317-21.

10.Fenster PE, Hager WD, Goodman MM. Digoxin-quinidine-spironolactone interaction. Clin Pharmacol Ther 1984 Jul;36(1):70-3.

11.Pedersen KE, Lysgaard Madsen J, Klitgaard NA, Kjaer K, Hvidt S. Effect of quinine on plasma digoxin concentration and renal digoxin clearance. Acta Med Scand 1985;218(2):229-32.

12.Angelin B, Arvidsson A, Dahlqvist R, Hedman A, Schenck-Gustafsson K. Quinidine reduces biliary clearance of digoxin in man. Eur J Clin Invest 1987 Jun;17(3):262-5.

13.Hedman A, Angelin B, Arvidsson A, Dahlqvist R, Nilsson B. Interactions in the renal and biliary elimination of digoxin: stereoselective difference between quinine and quinidine. Clin Pharmacol Ther 1990 Jan;47(1):20-6.

14.Hedman A. Inhibition by basic drugs of digoxin secretion into human bile. Eur J Clin Pharmacol 1992;42(4):457-9.

15.Williams PJ, Lane J, Murray W, Mergener MA, Kamigaki M. Pharmacokinetics of the digoxin-quinidine interaction via mixed-effect modelling. Clin Pharmacokinet 1992 Jan;22(1):66-74.

16.US Food and Drug Administration (FDA). Drug Development and Drug Interactions: Table of Substrates, Inhibitors and Inducers. Available at: DrugInteractionsLabeling/ucm093664.htm. Updated 08/05/2011.

17.Lanoxin (digoxin) Tablets US prescribing information. Covis Pharmaceuticals, Inc. July, 2015.

Selected from data included with permission and copyrighted by First Databank, Inc. This copyrighted material has been downloaded from a licensed data provider and is not for distribution, expect as may be authorized by the applicable terms of use.

CONDITIONS OF USE: The information in this database is intended to supplement, not substitute for, the expertise and judgment of healthcare professionals. The information is not intended to cover all possible uses, directions, precautions, drug interactions or adverse effects, nor should it be construed to indicate that use of a particular drug is safe, appropriate or effective for you or anyone else. A healthcare professional should be consulted before taking any drug, changing any diet or commencing or discontinuing any course of treatment.

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