Infusion reactions, allergic-like reactions and hypersensitivity Serious adverse reactions to Herceptin infusion that have been reported infrequently include dyspnoea, hypotension, wheezing, hypertension, bronchospasm, supraventricular tachyarrythmia, reduced oxygen saturation, anaphylaxis, respiratory distress, urticaria and angioedema (see 4.8).