This medication is given by slow injection into a vein by a health care professional. It is given as directed by your doctor, usually once every 3 weeks. Your first infusion will be given over at least 90 minutes.

The dosage, the speed of your injection, and the length of time you receive trastuzumab emtansine is based on your body weight, medical condition, and response to treatment.

Infusion reactions may happen during the infusion of this drug and for up to 24 hours afterward. Your doctor may prescribe other medications (such as acetaminophen, diphenhydramine) before each treatment to help prevent these side effects. Tell your doctor right away if you have any symptoms of infusion reactions such as chills, fever, flushing, wheezing, shortness of breath, dizziness, or fast heartbeat. Your doctor may slow down or stop your treatment for some time.

To get the most benefit from this medication, do not miss any doses. To help you remember, mark your calendar with a reminder.