
Lapatinib is used in combination to treat advanced or metastatic breast cancer that overexpresses the human epidermal growth factor receptor 2 (HER2) receptor. It is typically used in combination with Capecitabine or Letrozole.
Dose and Schedule
It is crucial to take Lapatinib as instructed to ensure the treatment is as effective as possible. Please keep the following key points in mind:
- Your dose may vary, but the usual dose of Lapatinib is:
- 1250 to 1500 milligrams, taken by mouth at a scheduled time once a day.
- Lapatinib should be taken on an empty stomach (1 hour before breakfast or 2 hours after breakfast), and at the same time each day.
- Lapatinib should be taken whole; do not crush, cut, or dissolve the tablets. If you have difficulty swallowing Lapatinib, consult your doctor for alternative options.
- If you miss a dose:
- Do not take an extra dose to make up for the missed one. Simply take your next dose at the regular time.
- Write down any missed doses and inform your doctor during your next visit.
Drug and Food Interactions
- Lapatinib interacts with several drugs. Be sure to inform your doctor of all prescription medications, over-the-counter medicines, vitamins, and herbal products you are taking.
- Grapefruit or grapefruit juice may interact with Lapatinib. Avoid consuming them during treatment.
- Before taking any new medications or supplements, or receiving any vaccines, consult your doctor or pharmacist.
Storage and Handling
- Handle Lapatinib with care, as it can be toxic, much like chemotherapy drugs. Limit exposure to others.
- Store Lapatinib at room temperature (below 25°C) in a dry place, away from light.
- Keep Lapatinib out of reach of children and pets.
- Leave Lapatinib in its provided packaging until ready to be taken.
- Whenever possible, take the medication yourself. If someone else needs to administer it, they should wear gloves when handling the tablets.
- Take the medicine immediately with water.
- Unused Lapatinib should not be thrown in the trash or flushed down the sink or toilet. Bring any unused medication back to your healthcare provider for safe disposal.
- When travelling, place your Lapatinib packaging in a sealed plastic bag. Ask your pharmacist if there are any additional travel precautions to consider.
Side Effects of Lapatinib
The following are common side effects experienced by about one-third of patients taking Lapatinib. However, you may not experience these side effects.
Decreased haemoglobin (part of red blood cells that carry oxygen) | A blood test will be done before starting each new cycle of Lapatinib to monitor your haemoglobin, white blood cells, platelet count, liver function, and kidney function. |
Changes in liver function | Contact your doctor immediately if you notice: |
– Yellowing of the skin or eyes | |
– Dark or brown urine | |
Fatigue | – Get 7–8 hours of sleep per night. – Balance work and rest. – Stay as active as possible, but rest when needed. – You may notice being paler than usual. |
Shortness of breath, chest discomfort, dizziness, palpitations | Contact your doctor immediately if you experience any of these symptoms. |
Diarrhoea (loose or urgent bowel movements) | – Drink 8–10 glasses of water or fluid daily (unless restricted by your doctor). – Eat small, frequent meals throughout the day. – Eat bland, low-fibre foods (e.g., bananas, potatoes, rice). – Avoid high-fibre foods, gas-producing foods, and spicy, fried, or greasy foods. – If bowel movements increase by four or more per day, consider using Loperamide (Imodium or Prodium) or Smecta. |
Rash or itchy skin | – Keep skin moisturised with creams and lotions. – Wear loose-fitting clothing. – Avoid perfumes, cologne, or excessive heat. – Your doctor may suggest antihistamines or topical creams. – Avoid prolonged sun exposure (10 am–4 pm), wear UV-protective clothing, broad-brimmed hats, and use sunscreen (SPF 30 or higher). |
Nausea or vomiting | – Eat and drink slowly. – Avoid strong odours. – Avoid vigorous exercise and lying down immediately after eating. |
Pain or discomfort in hands and/or feet (Hand-foot skin reaction – HFSR) | – Soak feet in a water bath with Epsom salt and gently exfoliate any callused skin. – Moisturise your hands and feet. – Avoid tight shoes and use cushioning for hands during activities that put pressure on them. |
Handling Body Fluids and Waste
Since Lapatinib can remain in your body for several days, it may be present in bodily fluids like urine, stool, sweat, or vomit. Follow these instructions to minimise exposure to others:
- Pregnant women should avoid touching anything that may be contaminated with body fluids from the patient.
- Toilets: Always close the lid and flush twice to ensure waste is properly discarded. Clean the toilet if it becomes soiled.
- Hand washing: Always wash hands with soap and water after using the toilet, handling contaminated items, or cleaning the toilet.
- If using a bedpan, ensure that caregivers wear gloves during clean-up and wash the bedpan with soap and water daily.
- If you experience incontinence, use disposable pads or diapers to absorb waste.
Pregnancy, Sexual Activity, and Contraception
- Women should not become pregnant, and men should not father a child while taking Lapatinib.
- Both men and women of childbearing potential should use effective contraception during therapy and for at least 1 week after the last dose of Lapatinib.
- Do not breastfeed while taking Lapatinib and for 1 week after the last dose.
- If you become pregnant, inform your doctor immediately.
Compiled by: Karin Mouton
Registered Oncology Nurse