Description: Lapatinib is a 4-anilinoquinazoline tyrosine kinase inhibitor of both Epidermal Growth Factor Receptor (EGFR [ErbB1]) and Human Epidermal Receptor Type 2 (HER2 [ErbB2]) receptors. It blocks the phosphorylation and activation of downstream 2nd messengers (Erk1/2 and Akt) which regulate cellular proliferation and survival of ErbB- and ErbB2-expressing tumours.

Onset: 30 sec (IV); 3-4 min (IM).

Duration: 5-10 min (IV); 12-25 min (IM).


Absorption:  Variable and incompletely absorbed. Systemic exposure is increased w/ food. Time to peak plasma concentration: Approx 4 hr.

Distribution: Plasma protein binding: >99% (albumin and α1 acid glycoprotein).

Metabolism: Undergoes extensive hepatic metabolism primarily via CYP3A4 and CYP3A5 isoenzymes, to a lesser extent via CYP2C19 and CYP2C8 isoenzymes.

Excretion: Via faeces approx 27% (parent lapatinib); approx 14% (metabolites). Terminal half-life: Approx 14 hr (single dose). Effective half-life: 24 hr (repeated dosing).

Lapatinib is the 2nd choice of treatment for HER2-positive breast cancer used together with another medication (capecitabine). It may also be used together with another medication (letrozole) to treat HER2-positive breast cancer in women after menopause. It works by slowing or stopping the growth of cancer cells.

How to use lapatinib

Read the Patient Information Leaflet provided by your pharmacist before you start using lapatinib and each time you get a refill. If you have any questions, consult your doctor or pharmacist.

Take this medication by mouth 1 hour before or 1 hour after a meal, usually once daily or as directed by your doctor. It is important that you do not take this medication more than once daily.

The dosage is based on your medical condition, response to treatment, and certain other drugs you may be taking.

Do not increase your dose or take this medication more often than prescribed. Your condition will not improve any faster, and the risk of serious side effects may be increased.

Avoid eating grapefruit or drinking grapefruit juice while being treated with this medication unless your doctor instructs you otherwise. Grapefruit can increase the amount of certain medications in your bloodstream. Consult your doctor or pharmacist for more details.

Since this drug can be absorbed through the skin and lungs, women who are pregnant or who may become pregnant should not handle this medication or breathe the dust from the tablets.

Follow your doctor’s instructions on how to correctly take capecitabine or letrozole with lapatinib.

Liver problems may occur. Speak to your doctor in order to be monitored for your liver.

  • Tell your doctor or pharmacist promptly if any of these effects persist or worsen:
    • Nausea
    • Vomiting
    • upset stomach
    • mouth sore
    • mild rash
    • dry skin
    • trouble sleeping

    Diarrhea is a common side effect and may become severe.

    This drug may sometimes cause your hands/feet to develop a skin reaction called hand-foot syndrome (palmar-plantar erythrodysesthesia). Tell your doctor immediately if you experience:

    • swelling
    • pain
    • redness
    • peeling
    • blisters
    • tingling/burning of the hands/feet

    Tell your doctor immediately if any of these unlikely but serious side effects occur:

    • unusual tiredness
    • shortness of breath
    • swelling ankles/feet

    Seek immediate medical attention if any of these rare but serious side effects occur:

    • fast/pounding/irregular heartbeat
    • dizziness
    • fainting

    A very serious allergic reaction to this drug is rare.

    This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.



    Before using this medication, tell your doctor or pharmacist of all prescription and nonprescription/herbal products you may use, especially of digoxin and drugs affecting liver enzymes that remove lapatinib from your body.

    Tell your doctor if you take other drugs from your body by affecting certain liver enzymes such as :

    • tacrolimus
    • trazodone
    • digoxin
    • cyclosporine
    • certain “statin” cholesterol medications (simvastatin, lovastatin, atorvastatin)

    Before using lapatinib, report all medications that may affect the heart rhythm you are currently using to your doctor or pharmacist such as:

    • dofetilide
    • pimozide
    • procainamide
    • amiodarone
    • quinidine
    • sotalol
    • macrolide antibiotics

    This document does not contain all possible interactions. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you, and share the list with your doctor and pharmacist.

  • Allergic reaction from this medication
  • Medical history of: heart disease (e.g., irregular heartbeat) or liver disease
  • Affected heart rythm (QT prolongation)
  • This medication is not recommended for use during pregnancy
  • breast-feeding while using this drug is not recommended

Consult your doctor or pharmacist regarding the precautions mentioned above.

If overdose is suspected, contact a poison control center or emergency room immediately.



Available Brands

Tykerb [ GlaxoSmithKline ]

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