DECREASED PLASMA-CONCENTRATIONS OF IMIPRAMINE AND DESIPRAMINE FOLLOWING CHOLESTYRAMINE INTAKE IN DEPRESSED-PATIENTS

The effect of cholestyramine (4 g t.i.d. for 5 days) on the steady-sta te plasma concentrations of imipramine and desipramine was assessed in six depressed patients receiving chronic treatment with imipramine (7 5-150 mg/day). Compared with baseline, cholestyramine treatment was as sociated with an average 23% decrease in plasma imipramine levels [fro m 211 +/- 95 to 159 +/- 67 nmol/L, (mean +/- SD), p < 0.05], whereas d esipramine levels decreased only marginally. These data suggest that a dministration of cholestyramine at therapeutic doses impairs the gastr ointestinal absorption of concurrently prescribed imipramine by an ext ent that is potentially clinically significant.