Dynamics of <smlcap>L</smlcap>-Carnitine in Plasma and Urine in Patients Undergoing Cisplatin Chemotherapy

<b><i>Background and Aims:</i></b> Several studies have indicated that cisplatin (<i>cis</i>-diamminedichloroplatinum II; CDDP) causes urinary excretion of <smlcap>L</smlcap>-carnitine (LC). However, the underlying cofactors affecting the increased urinary excretion remain unclear. The present study was performed to evaluate the dynamics of LC in plasma and urine after CDDP chemotherapy and to examine the relations with clinical parameters, such as gender, body mass index (BMI), and renal function. <b><i>Methods:</i></b> Twenty-two patients treated with CDDP therapy were selected. Blood and urine samples were taken from patients before starting CDDP treatment (day 0), on the next day (day 1), and on the seventh day (day 7). We measured plasma and urine concentrations of total, free, and acyl-LC, and examined the relationships with gender, age, treatment cycle, skeletal muscle mass, BMI, glomerular filtration rate, and change in creatinine concentration after CDDP administration. <b><i>Results:</i></b> Both urinary and plasma concentrations of 3 types of LC increased markedly on day 1 and subsequently reverted to the pre-CDDP level on day 7. There was a positive correlation between the % changes in plasma and urine LC (correlation coefficient 0.59, <i>p</i> = 0.003) on day 1, but no significant relations were seen in other clinical parameters. <b><i>Conclusions:</i></b> CDDP transiently increased plasma LC levels. The mechanism seemed to involve recruitment for marked urinary loss of LC. However, these changes in plasma and urinary LC levels were not related to clinical factors, suggesting that the dynamics of LC were independent of preexisting physical parameters.