Drug Interactions between amisulpride and lapatinib

MONITOR CLOSELY: Amisulpride can cause dose- and concentration-dependent prolongation of the QT interval. Theoretically, coadministration with other agents that can prolong the QT interval may result in additive effects and increased risk of ventricular arrhythmias including torsade de pointes and sudden death. In 40 healthy Caucasian and Japanese subjects, the maximum mean difference in QTcF (Fridericia corrected QT interval) from placebo after baseline correction was 5.0 ms following a 5 mg IV infusion over 2 minutes and 23.4 ms following a 40 mg IV infusion over 8 minutes. A maximum mean difference of 13.4 ms is predicted for a 10 mg IV infusion over 1 minute based on the exposure-QTcF response relationship identified from the data in the study. In general, the risk of an individual agent or a combination of agents causing ventricular arrhythmia in association with QT prolongation is largely unpredictable but may be increased by certain underlying risk factors such as congenital long QT syndrome, cardiac disease, and electrolyte disturbances (e.g., hypokalemia, hypomagnesemia). In addition, the extent of drug-induced QT prolongation is dependent on the particular drug(s) involved and dosage(s) of the drug(s).

MANAGEMENT: Caution and close clinical monitoring (e.g., electrocardiogram, serum electrolytes) are recommended if amisulpride is used in combination with other drugs that can prolong the QT interval. Patients should be advised to seek prompt medical attention if they experience symptoms that could indicate the occurrence of torsade de pointes such as dizziness, lightheadedness, fainting, palpitation, irregular heart rhythm, shortness of breath, or syncope.