Pharmacokinetics and interactions of digoxin, theophylline and furosemide in diseases with edema

In diseases with generalized edema caused by decompensated heart and liver diseases or kidney failure digitalis preparations, diuretics and theophylline -- if lung disease accompanies one of the above states -- are often used. Literature dealing with theophylline, digoxin and furosemide pharmacokinetics in edematous diseases was analyzed as well as theophylline or digoxin interactions with furosemide. The results obtained in these investigations are very dissimilar, even contradictory. In all the drugs investigated, it was found that serum drug concentration was reduced, that there were no changes in comparison with non-edematous diseases and that drug concentrations were elevated in edematous diseases. Many problems in this field remain unsolved requiring further investigations of digoxin, theophylline and furosemide pharmacokinetics in liver, heart and kidney diseases accompanied by edema. As these drugs are often administered in these states, and having in mind their narrow therapeutic range (digoxin, theophylline), intoxication or a drug concentration decrease below the possibility of inducing any therapeutic effect are possible.