The recommended course of treatment in the mitotane instructions

Mitotane is a drug with selective toxicity against adrenal cortical cells and is mainly used to treat adrenocortical cancer (Adrenocortical Carcinoma, ACC). The treatment plan of this drug must strictly follow the principle of individualization, and the dose should be dynamically adjusted based on the patient's weight, clinical response, and blood drug concentration. According to overseas instructions, the starting dose of mitotane is usually 2000 mg to 6000 mg (i.e. 2 to 6 grams) per day, and it is recommended to take it orally in three or four times. Its slow onset of action determines that the initial treatment should start with a medium dose and gradually increase the dose to ensure that the blood concentration gradually rises to the therapeutic window range.

In clinical practice, doctors usually decide whether to postpone the dosage increase based on the patient's tolerance and whether gastrointestinal discomfort, neurological side effects (such as fatigue, confusion, or ataxia) occur. The treatment goal is to maintain the concentration of mitotane in plasma between 14 and 20 mg/L, which is a recognized therapeutic concentration range that can exert anti-tumor effects while minimizing the risk of toxicity. Plasma concentrations should be monitored every 4 to 6 weeks, especially after dose adjustments or when a decrease in efficacy is suspected. It should be emphasized that when the mitotane concentration is higher than 20mg/L, the risk of central nervous system toxicity increases significantly, so once it is exceeded, the dose should be reduced immediately or treatment should be suspended.

The entire treatment cycle depends on the disease control situation and generally needs to be maintained for several months to several years. For patients with adrenocortical cancer after surgery, mitotane is often used as adjuvant therapy for long-term maintenance. Some studies have pointed out that the adjuvant therapy time is usually no less than 2 years. For advanced or metastatic cases, treatment may need to be continued until disease progression or intolerable adverse effects occur. Because mitotane can also affect hormone metabolism in the body, some patients need to receive cortisol replacement therapy at the same time to prevent adrenal insufficiency.

Reference materials:https://go.drugbank.com/drugs/DB00648