The Interaction Between Cholestyramine and Drugs

“…In addition, it has also been shown to bind thyroxine (17) and several drugs (7). Gallo and coworkers (7) showed that 33% of a digoxin solution was weakly bound by cholestyramine when combined in ratios which might be expected if average doses of the two drugs were taken together. Assuming average doses of 4 g for cholestyramine and 0.25 mg for digoxin, the cholestyramine: digoxin ratio on a weight basis would be 16,000: 1.…”

Section: Discussionmentioning

confidence: 99%

Interruption of the enterohepatic circulation of digitoxin by cholestyramine

Caldwell¹,

Greenberger²

1971

J. Clin. Invest.

View full text Add to dashboard Cite

A B S T R A C T Previous studies have demonstrated that considerable amounts of parenterally administered cardiac glycosides are excreted in the bile and reabsorbed across the intestinal mucosa in several species. It is currently believed that the more prolonged action of nonpolar digitalis glycosides is due to their retention and recycling in the enterohepatic circulation. This report describes studies carried out to evaluate the effects of pharmacologic interruption of this enterohepatic cycle with the intraluminal sequestering agent cholestyramine.Cholestyramine was found to bind substantial quantities of digitoxin-8H and digoxin-8H in vitro and this binding was only modestly inhibited by the presence of bile. Administration of cholestyramine to rats by intragastric catheter before the subcutaneous injection of the LD1oo dose of digitoxin (10 mg/kg) resulted in a 70% survival rate. Further, oral administration of cholestyramine to rats before the subcutaneous injection of digitoxin-8H resulted in accelerated fecal excretion of radioactivity and lower levels of digitoxin-3H and metabolites in brain tissue compared to controls. Similarly, pretreatment of guinea pigs with cholestyramine orally before the injection of digitoxin in dosages of 10.0 and 4.0 mg/kg resulted in a 25 and 70% survival rate respectively as compared to survival rates of 0 and 30% in control animals. Cholestyramine pretreatment of guinea pigs was also accompanied by lower levels of digitoxin-2H and metabolites in heart and liver 90 min after injection of digitoxin-3H. Cholestyramine therapy did not result in significant changes in serum potassium levels excluding the possibility that drug-induced hyperkalemia might have affected the cardiac uptake of digitoxin.

show abstract

“…However, cholestyramine interferes with the absorption of many acidic drugs but it may also affect basic or non charged drugs (Gallo et al, 1965).…”

mentioning

confidence: 99%