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Tykerb is an oral tablet consisting of a cancer medicine called lapatinib. We carry the brand choice of Tykerb in 250mg. 

Tykerb is used for the treatment of breast cancer (hormone-related or HER2-positive) that has progressed or spread following treatment with other medications. This medication may be prescribed to you along with other medications.  Breast cancer that has many receptors for either estrogen or progesterone will be considered HER2-positive.

Tykerb (lapatinib) is effective at treating (hormone-related or HER2-positive) breast cancer because this drug is able to slow- and sometimes completely stop- the growth of cancer cells.

Need to know; use Tykerb exactly the way your doctor has prescribed it to you. Directions can commonly be found on the prescription label if you forget. Ensure you are taking all prescribed medications for your treatment. This medication may be taken differently depending on if you take other medications for the same treatment. Ensure you know exactly how your doctor wants you to take the medication. You may need blood tests every 4-6 weeks (28-42 days) to ensure your liver function is working properly. Your heart function may also need to be checked.

How to take Tykerb; this medication is best taken on an empty stomach; you should take your dose at least 1 hour before or after eating a meal. You may swallow the tablets (if you have multiple prescribed medications) individually, one at a time, but you must take them all within the same few minutes.

When used with Ferma, the common dose of Tykerb is 6 tablets once a day.

When used with Xeloda, the common dose of Tykerb is 5 tablets per day for 21 days, taking 2 Xeloda tablets twice a day for the first 14 days (half) of the cycle. Once the 21 days is complete, the cycle is restarted.

No matter which medications you take with Tykerb, only your doctor will be able to determine your exact dose and treatment duration. Store at room temperature, away from risks of heat and moisture.


Do not use this medication if you are pregnant or if you are allergic to lapatinib.

Dose adjustment or special precautions may be required

To use this medication safely, tell your doctor if you have heart disease, liver disease, and electrolyte imbalance, or a personal or family history of long QT syndrome.


Tykerb has the potential to cause liver problems. This complication can be serious and even fatal. If you notice signs of liver damage while using this medication, contact your doctor right away. (See side effects).

Tykerb can cause birth defects or serious harm to an unborn baby. You should use effective birth control methods while being treated with Tykerb.

It is not known if this medication will pass into breast milk or if it will harm a nursing infant.

Side Effects

Common side effects of Tykerb (lapatinib) may include:

indigestion, loss of appetite; nausea, vomiting, diarrhea; rash, itching, dry skin; pain or redness on the palms of your hands or the soles of your feet; problems with your fingernails or toenails; feeling weak or tired; nosebleeds, mouth sores; thinning hair; or headache.

The above side effects should not alarm you.

Serious side effects of Tykerb (lapatinib) may include:

a headache with chest pain and severe dizziness, fainting, fast or pounding heartbeats; severe or ongoing diarrhea; new or worsening cough, wheezing, chest pain, feeling short of breath;

liver problems: nausea, upper stomach pain, itching, tired feeling, flu-like symptoms, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes); or

severe skin reaction: fever, sore throat, swelling in your face or tongue, burning in your eyes, skin pain followed by a red or purple skin rash that spreads (especially in the face or upper body) and causes blistering and peeling.

If you have any of the above side effects or signs of complications, contact your doctor right away.

Please note this is not a complete list of side effects. Not everyone experiences side effects; they are not guaranteed. If you do have side effects and they become unmanageable, consult your doctor about alternate medications.


What other medications may cause a drug interaction to occur?

Some medications that may interact with Tykerb include dexamethasone, letrozole, Nexium (esomeprazole), prochlorperazine, sertraline, and venlafaxine.

What should I avoid while using Tykerb?

During treatment with Tykerb, you should avoid all grapefruit products. Grapefruit can increase the effect of Tykerb, which can lead to serious and unpleasant side effects.

Can children use this medication?

The safety and effectiveness of Tykerb have not been established in pediatric patients. Some doctors may prescribe this medication a person under 18, but only under certain circumstances.

What is the average dose for an adult with HER2-positive metastatic breast cancer?

*** Doses can only be determined by your doctor. Do not use this dosage if it is different from what your doctor prescribed to you. ***

The average dose for an adult with HER2-positive metastatic breast cancer is 1,250mg given orally once per day for 21 consecutive days. Other medications may also be used for a partial amount of this 21 day cycle.

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