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Herceptin Hylecta Side Effects

Generic name: hyaluronidase / trastuzumab

Medically reviewed by Last updated on Nov 11, 2023.

Note: This document contains side effect information about hyaluronidase / trastuzumab. Some dosage forms listed on this page may not apply to the brand name Herceptin Hylecta.

Applies to hyaluronidase / trastuzumab: subcutaneous solution.


Subcutaneous route (Solution)

Cardiomyopathy: Trastuzumab/hyaluronidase-oysk can result in subclinical and clinical cardiac failure manifesting as congestive heart failure, and decreased left ventricular ejection fraction, with greatest risk when administered concurrently with anthracyclines. Evaluate cardiac function prior to and during treatment. Discontinue trastuzumab/hyaluronidase-oysk for cardiomyopathy.Pulmonary Toxicity: Discontinue trastuzumab/hyaluronidase-oysk for anaphylaxis, angioedema, interstitial pneumonitis or acute respiratory distress syndrome.Embryo-Fetal Toxicity: Exposure to trastuzumab/hyaluronidase-oysk during pregnancy can result in oligohydramnios, in some cases complicated by pulmonary hypoplasia and neonatal death. Advise patients of these risks and the need for effective contraception.

Serious side effects of Herceptin Hylecta

Along with its needed effects, hyaluronidase / trastuzumab may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor or nurse immediately if any of the following side effects occur while taking hyaluronidase / trastuzumab:

More common

Less common

Incidence not known

Other side effects of Herceptin Hylecta

Some side effects of hyaluronidase / trastuzumab may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

Less common

For Healthcare Professionals

Applies to hyaluronidase / trastuzumab: subcutaneous solution.


Very common (10% or more): Neutropenia (44%), anemia (12%), leukopenia (11%)

Common (1% to 10%): Febrile neutropenia[Ref]


Very common (10% or more): Hypersensitivity (10%)[Ref]


Very common (10% or more): Infection (20%), influenza syndrome (10%)

Common (1% to 10%): Viral infection

Postmarketing reports: Immune thrombocytopenia[Ref]


Very common (10% or more): Injection site reaction/complication (e.g., joint pain, bruising, dermatitis, discoloration, discomfort, erythema, extravasation, fibrosis, hematoma, hemorrhage, hypersensitivity, induration, inflammation, irritation, macule, mass, nodule, edema, pallor, paresthesia, pruritus, rash, reaction, swelling, ulcer, vesicles, warmth) (10%)[Ref]


Very common (10% or more): Myalgia (21%), arthralgia (18%), asthenia (12%), back pain (11%), pain in extremity (10%)

Common (1% to 10%): Bone pain[Ref]


Very common (10% or more): Decreased appetite (20%)[Ref]


Very common (10% or more): Insomnia (14%)

Common (1% to 10%): Depression[Ref]


Common (1% to 10%): Urinary tract infection[Ref]


Common (1% to 10%): Liver function abnormal[Ref]


Postmarketing reports: Tumor lysis syndrome (TLS)


Very common (10% or more): Upper respiratory tract infection (24%), cough (22%), rhinitis (14%), pharyngitis (12%)

Common (1% to 10%): Dyspnea, epistaxis, nasal inflammation/discomfort, sinusitis[Ref]


Very common (10% or more): Fatigue (46%), chills (32%), edema (14%), pyrexia (13%)

Common (1% to 10%): Pain

Postmarketing reports: Oligohydramnios or oligohydramnios sequence (including pulmonary hypoplasia, skeletal abnormalities, and neonatal death)[Ref]

Nervous system

Very common (10% or more): Peripheral neuropathy (20%), headache (17%), dizziness (13%), dysgeusia (10%)

Common (1% to 10%): Paresthesia, peripheral neuritis, neuropathy[Ref]


Postmarketing reports: Glomerulopathy[Ref]


Very common (10% or more): Flushing (14%)

Common (1% to 10%): Hypertension, arrhythmia, ejection fraction decreased, left ventricular dysfunction, tachycardia, congestive heart failure[Ref]


Very common (10% or more): Alopecia (63%), rash (26%), nail disorder (14%)

Common (1% to 10%): Pruritus, nail discoloration, erythema, herpes simplex, acne[Ref]


Very common (10% or more): Nausea (49%), diarrhea (34%), vomiting (23%), stomatitis (21%), abdominal pain (14%), dyspepsia (11%), mucosal inflammation (10%)

Common (1% to 10%): Constipation, stomatitis[Ref]

Frequently asked questions


1. Product Information. Herceptin Hylecta (hyaluronidase-trastuzumab). Genentech. 2019.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.