Read the Patient Information Leaflet if available from your pharmacist before you start taking tucatinib and each time you get a refill. If you have any questions, ask your doctor or pharmacist.

Take this medication by mouth with or without food as directed by your doctor, usually twice daily (about 12 hours apart). Swallow the medication whole. Do not chew, crush, or split the tablets. Do not take tablets if they are broken, cracked, or damaged.

If you miss a dose or vomit after taking tucatinib, do not take another dose. Take your next dose at the regular time.

Use this medication regularly to get the most benefit from it. To help you remember, take it at the same times each day.

The dosage is based on your medical condition and response to treatment. Do not increase your dose or use this drug more often or for longer than prescribed. Your condition will not improve any faster, and your risk of serious side effects will increase.

Since this drug can be absorbed through the skin and lungs and may harm an unborn baby, women who are pregnant or who may become pregnant should not handle this medication or breathe the dust from the tablets.