Short-term variation in plasma mitotane levels confirms the importance of trough level monitoring

T.M.A. Kerkhofs*, L.J.J. Derijks, M.H.T. Ettaieb, E.M. Eekhoff, C. Neef, H. Gelderblom, J. den Hartigh, H.J. Guchelaar, H.R. Haak

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review


Objective: Mitotane is the drug of choice in patients with adrenocortical carcinoma. The anti-neoplastic effect is correlated with mitotane plasma levels, which render it crucial to reach and maintain the concentration above 14 mg/l. However, mitotane pharmacokinetics is poorly understood. The aim of this study was to investigate the variation in plasma mitotane levels during the day and the influence of a single morning dose.

Design: A prospective case-control study was conducted to investigate the variation in plasma mitotane levels.

Methods: Patients who had been treated for at least 24 weeks and had reached the therapeutic plasma level (14 mg/l) at least once were eligible. In the first group, mitotane levels were determined hourly for the duration of 8 h after administration of a single morning dose. In the second group, mitotane levels were assessed similarly without administration of a morning dose.

Results: Ten patients were included in this study, and three patients participated in both groups. Median plasma level at baseline was 16.2 mg/l (range 11.3-23.3 mg/l) in the first group (n=7) and 17.0 mg/l (13.7-23.8) in the second group (n=6). Plasma levels displayed a median increase compared with baseline of 24% (range 6-42%) at t=4 after morning dose and a change of 13% (range K14 to 33%) at t=4 without morning dose (P=0.02).

Conclusion: A substantial increase in mitotane plasma levels was observed in steady-state patients within a period of 8 h after morning dosing. Without morning dose, mitotane curves showed a variable profile throughout the day. This implies that random sampling could yield incidentally high levels. For this reason, we recommend early-morning trough sampling as standard management in monitoring mitotane treatment.

Original languageEnglish
Pages (from-to)677-683
Number of pages7
JournalEuropean Journal of Endocrinology
Issue number6
Publication statusPublished - Dec 2014


  • O,P'DDD

Cite this