Chronopharmacology of etoposide given by low dose prolonged infusion in lung cancer patients

We examined the chronopharmacology of prolonged etoposide administration by intravenous infusion over 14 days in 9 patients with lung cancer. Blood samples were obtained every 4 hours between 24 hours and 48 hours after initiation of the infusion. Using the unpaired t-test, the percentage plasma etoposide concentration at 09:00 hours calculated from the 24 hour average value, was significantly higher than that at 21:00 hours (p = 0.024). However, neither ANOVA nor cosinor analysis revealed any significant effect of sampling time (ANOVA: p = 0.29, cosinor analysis: p = 0.46).