What Should I Tell My Healthcare Provider Before Taking Lapatinib?
You should talk with your healthcare provider prior to taking this medication if you have:
- An irregular heart rhythm (arrhythmia), especially long QT syndrome
- Low blood potassium (hypokalemia) or magnesium (hypomagnesemia)
- Congestive heart failure
- Liver disease, including liver failure or cirrhosis
- Any allergies, including allergies to food, dyes, or preservatives.
Also, let your healthcare provider know if you are:
- Pregnant or thinking of becoming pregnant
- Breastfeeding.
Make sure to tell your healthcare provider about all other medicines you are taking, including prescription and non-prescription medicines, vitamins, and herbal supplements.
Lapatinib belongs to a group of medications called
tyrosine kinase inhibitors. It works inside of cancer cells. Lapatinib binds to the inside of two types of receptors: epidermal growth factor receptor (EGFR) and human epidermal receptor type 2 (HER2). These two receptors are important for the growth of
breast cancer and cells, and lapatinib (when used in combination with
capecitabine) helps to slow down the growth of cancer cells.
In one study, lapatinib was added to capecitabine for treating breast cancer that had spread to other parts of the body. The people in this study had already tried other types of chemotherapy medications unsuccessfully. Those who took the combination of lapatinib plus capecitabine had a longer period of time before their cancer became worse (27.1 weeks on average, compared to 18.6 weeks for those taking just capecitabine).