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Effect of sulfasalazine on digoxin bioavailability.
Clinical Pharmacology and Therapeutics
|October 1, 1976
Summary
Sulfasalazine (SSA) significantly reduces digoxin bioavailability, lowering serum digoxin levels. This interaction impacts digoxin
Area of Science:
- Pharmacology
- Drug Interactions
Background:
- Digoxin is a crucial medication for treating heart conditions.
- Concurrent use of digoxin and sulfasalazine (SSA) has been associated with reduced digoxin efficacy.
- The mechanism of this interaction requires further investigation.
Purpose of the Study:
- To investigate the effect of sulfasalazine (SSA) on the bioavailability of digoxin.
- To determine if SSA consistently interferes with the therapeutic effect of digoxin.
Main Methods:
- A crossover study involving 10 healthy subjects.
- Subjects received digoxin (0.5 mg elixir) alone and after 6 days of SSA treatment.
- Serum digoxin levels and urinary excretion were measured.
Main Results:
- Co-administration of SSA with digoxin reduced the average area under the serum digoxin curve by 24% (p < 0.05).
- Total urinary excretion of digoxin decreased by 18% (p < 0.025) when given with SSA.
- In vitro tests showed SSA did not significantly adsorb digoxin from solution.
Conclusions:
- Sulfasalazine (SSA) significantly reduces digoxin bioavailability, likely by affecting absorption rather than physical adsorption.
- This interaction necessitates careful monitoring of digoxin levels in patients also taking SSA.
- Further research may be needed to elucidate the precise mechanism of SSA's interference with digoxin absorption.
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