Abstract
We studied the effect of THC upon the pharmacokinetics of cyclophosphamide (CTX) and doxorubicin (ADR). Plasma THC was determined by RIA. Plasma concentrations of CTX and ADR were measured by GLC and fluorescence, respectively. RIA confirmed plasma levels of THC greater than 20 ng/ml for patients who received THC. CTX half-life was not significantly changed with use of THC (7.7 +/- 3.6 hours without versus 5.25 +/- 2.6 hours with THC). ADR half-life with THC was greater than without THC (175 +/- 197 hours versus 92 +/- 92 hours, respectively). Total drug exposure as determined by areas under the curves were similar (12.4 +/- 6 microM . hr without versus 13.8 +/- 4 microM . hr with THC). These preliminary data suggest that RIA is reliable for assessing THC plasma concentrations. THC induces no apparent alterations of CTX or ADR pharmacokinetics.