Trastuzumab  

Brand name: Herceptin®  

Generic name:Trastuzumab  

Therapeutic Class: monoclonal antibody
 

Manufacturer / Distributor:  Roche  

Availability: Trastuzumab is available by prescription only  

Indications: Trastuzumab is used along with other medications to treat metastatic HER2 (Human Epidermal Growth Factor Receptor-2)+ breast cancer, an aggressive form of breast cancer. The drug is often used in combination with paclitaxel or the first-line treatment of HER2-overexpressing metastatic breast cancer.  

Trastuzumab is also indicated as a single agent for the treatment of breast cancer with HER2 overexpression after surgery, chemotherapy and / or radiotherapy. Trastuzumab may also be prescribed for other medical conditions not mentioned in this article. Talk to your doctor or pharmacist for more information.   

Dosage form: Trastuzumab is given by injection into a vein 

Dosage: the dose of Gemzar recommended by your doctor depends on the type of cancer being treated, the overall state of your health, and your body mass index (your weight and height).  

Trastuzumab comes as a liquid to be injected into a vein. The drug is usually given once a week as a single agent (monochemotherapy), or once every 3 weeks along with other chemotherapy medications (polychemotherapy). In the absence of complications, Trastuzumab is usually taken for long term to increase the chance of recovery.  

However, the drug may cause hypersensitivity reactions during the first course of the therapy: fever, dyspnea, hypotension, and flushing. More rarely, Trastuzumab can cause pulmonary edema and severe cardio-pulmonary problems. In fact, some patients that have been treated with Trastuzumab experience life-threatening heart problems. Therefore, during treatment with Trastuzumab, regular cardiac exams, every 8 to 10 weeks, are particularly necessary.  

Trastuzumab should be administered with great care by medical professionals such as oncologists or physicians who have experience in chemotherapy drugs. Trastuzumab should be given in a hospital or similar institution that has access to sterilization equipments for its preparation. 

Overdose: Trastuzumab overdose can be fatal. An overdose of Trastuzumab can result in a decrease in white blood cells and platelets, which can cause serious or life threatening health problems in some patients. In addition, Trastuzumab overdose can also lead to kidney problems and/or severe heart problems. Therefore, avoid anything that can weaken your immune system and the risk of infection. During the treatment, keep all appointments with your doctor and laboratory. Tell your doctor about all abnormal symptoms you experience.  

Missing dose: because Trastuzumab is administered in hospital, missing dose is basically difficult if you respect your doctor’s appointments promptly. If for some reasons you cannot be present at the hospital for the therapy, contact your oncologist before the date you are scheduled for the injection.  Do not stay home because you are experience side effects; Trastuzumab cause side effects in most patients. Missing a dose or a session of the therapy can affect the entire treatment.    

Contraindication: Trastuzumab is contraindicated in the following conditions: 

• allergy to Trastuzumab or any of its ingredients 
• severe respiratory disorders 
• serious heart disease. 

Mechanism of action (MOA): Trastuzumab is a human IgG 1 type monoclonal antibody directed against the receptor 2 epidermal growth factor (HER2). It works by inhibiting or stopping the growth of cancer cells that overexpress HER2.  

Interactions:  talk you to your doctor before taking vitamins or nutritional supplements. Some medications are not recommended to be used along with Trastuzumab; they can decrease the healing power of the drug, or increase the risk of developing side effects. Consult your doctor before taking these medicines:  

• Ganciclovir, an antiviral drug 
• Azathioprine, an immune system inhibitor 
• Barbiturates, depressant drug that causes relaxation and sleepiness
• Cimetidine , a drug used to inhibit the production of acid in the stomach
• Colchicines , a medication used to treat pain of gouty arthritis
• Live vaccines: BCG vaccine, yellow fever vaccine, etc.
• Cyclophosphamide (Cytoxan), a medication of the alkylating agent family used to treat a variety of cancers
• Celecoxib, a non-steroidal anti-inflammatory drug (NSAID) used in the treatment of osteoarthritis, rheumatoid arthritis, painful menstruation, colon and rectum polyps, etc. 

Side effects: while attacking cancer cells, Trastuzumab also affects healthy cells, which cause adverse effects in most patients.  Common Trastuzumab side effects include:   

• hair loss
• constipation
• diarrhea
• difficulty sleeping
• fever
• nausea and vomiting
• infusion reactions
• increased cough
• headache
• fatigue
• rash
• low white and red blood cells
• Muscle pain.  

If the side effects above persist for weeks, contact your oncologist. In addition, contact your doctor if you experience any of these symptoms:  

• anxiety 
• depression
• nose bleeding
• fast or irregular heart beat
• chest pain
• shortness of breath
• dizziness
• intense head ache
• wheezing
• feeling of constriction of the throat
• swelling of feet or lower legs
• painful or difficult urination which  contain blood
• Pain in lower back or in the side, accompanied by fever or chills