In case of acute or chronic overdosage, the observed side effects are amplified. The extent of bone marrow depression, at the extreme agranulocytosis accompanied by necrotising angina and critical thrombocytopenia, determines the further course in acute and chronic overdosage. Ulceration of the mouth and gastrointestinal tract, haemorrhagic enterocolitis with massive bleeding, diarrhoea and persistent signs of renal and hepatic toxicity can occur.
If aplasia of the bone marrow occurs as a result of acute overdosage with mitoxantrone, it will from existing experience persist longer (approximately 3 weeks).
In patients with acute leukaemia, it can result in pronounced stomatitis in isolated cases. Appropriate measures for prophylaxis and treatment should therefore be taken.
Acute cardiac symptoms of different severity are possible in isolated cases.
If overdosage is diagnosed, a consequent infection prophylaxis with antibiotics must be initiated. To counteract agranulocytosis and thrombocytopenia, whole blood transfusions, leucocyte and thrombocyte concentrates are suitable. The usual supportive measures (maintenance of fluid and electrolyte balance, monitoring of renal and hepatic functions, strict cardiovascular monitoring, prophylaxis against candidiasis, etc) are to be carried out under inpatient control. Each overdosage requires careful monitoring of the clinical findings to identify possible delayed complications in time.