Tykerb Overdosage

There is no specific antidote for the inhibition of EGFR (ErbB1) and/or HER2 (ErbB2) tyrosine phosphorylation. The maximum oral dose of lapatinib that has been administered in clinical studies is 1800 mg once daily.
Asymptomatic and symptomatic cases of overdose have been reported in patients being treated with Tykerb. In patients who took up to 5000 mg of lapatinib, symptoms observed include known lapatinib associated events (see Adverse Reactions) and in some cases sore scalp and/or mucosal inflammation. In a single case of a patient who took 9000 mg of Tykerb, sinus tachycardia (with otherwise normal ECG) was also observed.
Lapatinib is not significantly renally excreted and is highly bound to plasma proteins, therefore haemodialysis would not be expected to be an effective method to enhance the elimination of lapatinib.
Further management should be as clinically indicated or as recommended by the national poisons centre, where available.