Kadcyla Side Effects

Generic name: ado-trastuzumab emtansine

Medically reviewed by Drugs.com. Last updated on Mar 18, 2025.

Note: This document provides detailed information about Kadcyla Side Effects associated with ado-trastuzumab emtansine. Some dosage forms listed on this page may not apply specifically to the brand name Kadcyla.

Applies to ado-trastuzumab emtansine: intravenous powder for solution.

Important warnings This medicine can cause some serious health issues

Intravenous route (powder for solution)

Do not substitute ado-trastuzumab emtansine with or for trastuzumab.

Hepatotoxicity, liver failure, reductions in left ventricular ejection fraction, and death have occurred in ado-trastuzumab emtansine-treated patients.

Monitor hepatic function and left ventricular function before beginning treatment and before each dose.

Modify, hold, or discontinue treatment as necessary.

Exposure to ado-trastuzumab emtansine during pregnancy can result in embryo-fetal harm.

Advise patients of these risks and the need for effective contraception.

Serious side effects of Kadcyla

Along with its needed effects, ado-trastuzumab emtansine (the active ingredient contained in Kadcyla) 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 ado-trastuzumab emtansine:

More common side effects

• black, tarry stools
• bladder pain
• bleeding gums
• bloating or swelling of the face, arms, hands, lower legs, or feet
• bloody or cloudy urine
• blurred vision
• burning, numbness, tingling, or painful sensations
• chills
• cough
• decreased urine
• difficult or labored breathing
• difficult, burning, or painful urination
• dizziness
• dry mouth
• fever
• frequent urge to urinate
• headache
• increased thirst
• irregular heartbeat
• loss of appetite
• lower back or side pain
• mood changes
• muscle pain or cramps
• nausea
• nervousness
• nosebleeds
• numbness or tingling in the hands, feet, or lips
• pale skin
• pinpoint red spots on the skin
• pounding in the ears
• rapid weight gain
• seizures
• slow or fast heartbeat
• sore throat
• stomach pain
• tightness in the chest
• troubled breathing with exertion
• ulcers, sores, or white spots in the mouth
• unsteadiness or awkwardness
• unusual bleeding or bruising
• unusual tiredness or weakness
• unusual weight gain or loss
• vomiting
• weakness in the arms, hands, legs, or feet

Less common side effects

• chest pain
• dilated neck veins
• extreme tiredness or weakness
• general feeling of discomfort or illness
• irregular breathing
• skin rash
• thickening of bronchial secretions

Rare side effects

• dark urine
• general feeling of tiredness or weakness
• light-colored stools
• stomach bloating
• vomiting blood
• yellow eyes or skin

Incidence not known

• agitation
• confusion
• decreased awareness or responsiveness
• depression
• hostility
• irritability
• itching
• joint pain, stiffness, or swelling
• loss of consciousness
• muscle twitching
• severe sleepiness
• stomach tenderness or cramps

Other side effects of Kadcyla

Some side effects of ado-trastuzumab emtansine 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 side effects

• belching
• change in taste
• constipation
• diarrhea
• difficulty with moving
• heartburn
• indigestion
• lack or loss of strength
• loss of taste
• muscle stiffness
• stomach discomfort or upset
• swelling or inflammation of the mouth
• trouble sleeping

Less common side effects

• burning, dry, or itching eyes
• discharge or excessive tearing
• redness, pain, or swelling of the eye, eyelid, or inner lining of the eyelid

For healthcare professionals

Applies to ado-trastuzumab emtansine: intravenous powder for injection.

Cardiovascular adverse events

• Common (1% to 10%): Left ventricular dysfunction, hypertension, peripheral edema^[Ref]

Dermatologic

• Very common (10% or more): Rash (12%)
• Common (1% to 10%): Pruritus, alopecia, nail disorder, palmar-plantar erythrodysesthesia syndrome, urticaria^[Ref]

Gastrointestinal

• Very common (10% or more): Nausea (40%), constipation (24%), vomiting (20%), diarrhea (20%), dry mouth (16%), abdominal pain (16%), stomatitis (15%), stomatitis
• Common (1% to 10%): Dyspepsia, gingival bleeding^[Ref]

Genitourinary

• Very common (10% or more): Urinary tract infection (12%)^[Ref]

Hematologic

• Very common (10% or more): Hemorrhage (35%), thrombocytopenia (25%), anemia (15%), hemorrhage
• Common (1% to 10%): Neutropenia, leucopenia^[Ref]

Hepatic

• Very common (10% or more): Transaminases increased (12%)

Common (1% to 10%):

• Uncommon (0.1% to 1%): Hepatotoxicity, hepatic failure, nodular regenerative hyperplasia, portal hypertension
• Rare (0.01% to 0.1%): Portal hypertension, hepatic failure, nodular regenerative hyperplasia^[Ref]

Hypersensitivity

• Common (1% to 10%): Hypersensitivity^[Ref]

Immunologic

• Common (1% to 10%): Immunogenicity^[Ref]

Metabolic

• Very common (10% or more): Hypokalemia (11%)
• Common (1% to 10%): Blood alkaline phosphatase increased^[Ref]

Musculoskeletal

• Very common (10% or more): Musculoskeletal pain (36%), arthralgia (19%), myalgia (13%)^[Ref]

Nervous system

• Very common (10% or more): Headache (28%), peripheral neuropathy (23%), asthenia, chills
• Common (1% to 10%): Dizziness, dysgeusia, memory impairment^[Ref]

Ocular

• Common (1% to 10%): Dry eye, conjunctivitis, blurred vision, lacrimation increased^[Ref]

Other

• Very common (10% or more): Fatigue (37%), pyrexia (23%), asthenia (16%), chills (10%)^[Ref]

Psychiatric

• Very common (10% or more): Insomnia (12%)^[Ref]

Respiratory

• Very common (10% or more): Epistaxis (24%), cough (20%), dyspnea (13%)
• Uncommon (0.1% to 1%): Pneumonitis^[Ref]

Local

• Uncommon (0.1% to 1%): Injection site extravasation, infusion-related reactions^[Ref]

Frequently asked questions

• What are monoclonal antibodies?
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• How long can you take Kadcyla?
• Is Kadcyla a chemotherapy drug? How does it work?
• Does Kadcyla cross the blood brain barrier?

Further information

Kadcyla side effects can vary depending on the individual. Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Note: Medication side effects may be underreported. If you are experiencing side effects that are not listed, submit a report to the FDA by following this guide.

Medical Disclaimer