Trastuzumab Side Effects: — Complete List and When to Call

Infusion reactions — fever, chills, nausea, headache — usually settle within a few hours of the infusion ending. They are most common with the first dose and tend to become milder or disappear by the third or fourth infusion. Trastuzumab is given as day care at CION centres, so nursing staff are present throughout and can manage any reaction as it happens. If you had a significant reaction to a previous dose, tell your team before the next so they can adjust the pre-medications accordingly.

If your echocardiogram shows a significant drop in ejection fraction, your oncologist will usually pause trastuzumab while your heart recovers, and may refer you to a cardiologist. In many cases, the drug can be restarted once ejection fraction has returned toward baseline. Whether to restart is a careful decision that weighs the degree of cardiac change against how well trastuzumab is working for your cancer. Your team will explain the options specific to your situation.

Trastuzumab alone tends to cause less severe fatigue than most chemotherapy regimens. When it is given alongside chemotherapy — which is common — the fatigue is mainly from the chemotherapy rather than trastuzumab. Once chemotherapy ends and you continue trastuzumab on its own, many people find their energy improves noticeably. If fatigue is stopping you from managing normal daily activities and has not improved over time, tell your team — it may reflect a cardiac effect worth checking, or something else treatable.

No. Heart scans are scheduled at specific intervals throughout the treatment course, not before every dose. The exact schedule depends on your individual risk, your baseline heart function, and whether a previous scan showed any change. ASCO and NCCN guidance recommends cardiac monitoring at regular intervals during trastuzumab treatment. Your oncologist will tell you the schedule planned for you. If you are unsure when your next scan is due, ask at your next infusion appointment rather than waiting.

Most common medicines are safe to continue, but always tell your oncology team everything you are taking — prescription medicines, over-the-counter tablets, herbal preparations, and Ayurvedic supplements. Some medicines affect the same cardiac pathways that trastuzumab monitoring tracks, and your team cannot interpret your scan results accurately without knowing the full picture. If you start anything new between appointments, let them know before your next infusion rather than waiting until it is convenient.