Lapatinib raises the amount of Midazolam in your body. Over 24 hours, Midazolam taken by mouth rose by 45% and Midazolam given into a vein by 22%. So Midazolam can be stronger and last longer, more so when swallowed.
These medicines are often taken together with some care. Your doctor may change a dose, space them apart or check on you more often. Make sure your doctor and pharmacist know you take both.
What to do: Ask your doctor or pharmacist before using these together. They may check you more closely or change the plan.