If dyspnea, clinically significant hypotension, or severe hypersensitivity reactions occur, interrupt use and administer appropriate therapy, which may include epinephrine, corticosteroids, diphenhydramine, bronchodilators, and oxygen. Monitor patients until signs and symptoms completely resolve. Strongly consider discontinuation for patients who develop anaphylaxis, angioedema, or acute respiratory distress syndrome. There is little information about retreatment following a severe hypersensitivity reaction, although drug has been readministered to some patients who fully recovered from a previous severe reaction. Even though some patients tolerated retreatment, others had severe reactions again, despite use of prophylactic premedications.
Hematologic toxicity is infrequent following trastuzumab use as a single agent.
An increased incidence of diarrhea, mainly mild to moderate in severity, was seen in patients given trastuzumab with chemotherapy. Rarely, severe infusion reactions leading to death within hours or up to 1 wk following infusion have been associated with use of the drug. More severe reactions usually were seen with initial drug infusion and generally occurred during or immediately after the infusion, although onset and clinical course varied. Some patients had symptoms that worsened progressively and led to more pulmonary complications, while others with acute onset of signs and symptoms experienced initial improvement followed by deterioration. Delayed postinfusion events with rapid deterioration also seen.