Can lapatinib (Tykerb) treat any type of breast cancer?

No. Although there are many different [types of breast cancer](https://www.goodrx.com/conditions/breast-cancer/breast-cancer-receptor-status-types), lapatinib (Tykerb) is used to treat certain HER2-positive metastatic breast cancers. Your provider will perform a [biopsy or surgery](https://www.cancer.org/cancer/breast-cancer/screening-tests-and-early-detection/breast-biopsy.html) to help figure out the [receptor type](https://www.goodrx.com/conditions/breast-cancer/breast-cancer-receptors) of your cancer. Knowing what type of receptor your cancer has will help them decide which treatment options to consider. Using lapatinib (Tykerb) also sometimes depends if you’ve tried other treatments for your cancer already. Discuss with your provider to see if lapatinib (Tykerb) is right for you.

What can I do to help with diarrhea that I get from lapatinib (Tykerb)?

If you experience diarrhea from lapatinib (Tykerb), you can help [manage](https://www.cancer.org/treatment/treatments-and-side-effects/physical-side-effects/stool-or-urine-changes/diarrhea.html) this side effect by watching what you eat and drink. Avoid spicy and greasy foods. Eating frequent, small, [bland meals](https://medlineplus.gov/ency/patientinstructions/000068.htm) can also help, but it’s best to follow this eating pattern for [short periods of time](https://www.goodrx.com/well-being/diet-nutrition/brat-diet-benefits-diarrhea-nausea) since it doesn’t provide enough nutrients for your overall health. Also make sure to stay hydrated by drinking plenty of water, broth, or sports drinks each day. In addition, you can lower your risk of skin irritation around the anus by cleaning the area with warm water and letting it dry completely. Let your provider know if you develop diarrhea. They can recommend other ways to manage or treat your diarrhea, including with medications like [loperamide (Imodium A-D)](https://www.goodrx.com/loperamide/what-is).

Is lapatinib (Tykerb) a kind of chemotherapy?

Lapatinib (Tykerb) is not a chemotherapy medication. [Chemotherapy](https://www.cancer.org/treatment/treatments-and-side-effects/treatment-types/chemotherapy.html) is a class of medication that kills cancer cells in your body. Lapatinib (Tykerb) doesn’t kill cancer cells but instead slows or stops cancer cell growth.

lapatinib

Generic Tykerb

Used for Breast Cancer

Lapatinib (Tykerb) is an oral medication used to treat certain types of breast cancer that has spread to other areas of the body (metastatic). This medication is only taken once a day, but it’s typically used together with another anticancer medication. Lapatinib (Tykerb) commonly causes diarrhea.

Reviewed by:

Lauren Morton, PharmD, BCPS

Cydnee Ng, PharmD

Last reviewed on December 12, 2022

What is Lapatinib (Tykerb)?

What is Lapatinib (Tykerb) used for?

HER2-positive metastatic breast cancer
HR-positive, HER2-positive metastatic breast cancer

How Lapatinib (Tykerb) works

Lapatinib (Tykerb) is a tyrosine kinase inhibitor (TKI). It works by blocking the action of specific proteins called human epidermal growth factor receptor 2 (HER2) and epidermal growth factor receptor (EGFR). HER2 and EGFR are both found on normal and cancer cells, and they play a role in cell growth.

In certain cancers, the cancer cells have more HER2 and EGFR proteins than normal cells. When these proteins are blocked by lapatinib (Tykerb), cancer cells can’t grow and spread as well.

Are you looking for information on Lenvima (lenvatinib) or Lorbrena (lorlatinib) instead?

Drug facts

Common Brands	Tykerb
Drug Class	Tyrosine kinase inhibitor
Controlled Substance Classification	Not a controlled medication
Generic Status	Lower-cost generic available
Availability	Prescription only

Common Brands

Tykerb

Drug Class

Tyrosine kinase inhibitor

Controlled Substance Classification

Not a controlled medication

Generic Status

Lower-cost generic available

Availability

Prescription only

Side effects of Lapatinib (Tykerb)

The following side effects may get better over time as your body gets used to the medication. Let your healthcare provider know immediately if you continue to experience these symptoms or if they worsen over time.

Common Side Effects

Diarrhea (up to 69%)
Rash (up to 54%)
Hand-foot syndrome (up to 53%)
Nausea (up to 44%)
Infection around the nails (up to 30%)
Vomiting (up to 26%)
Tiredness (up to 20%)
Lowered appetite (up to 18%)
Inflammation or reddening inside of the mouth (up to 17%)

^{*These side effects happened in people taking lapatinib (Tykerb) with other anticancer medications.}

Less Common Side Effects

Headache
Feeling weak
Dry or itchy skin
Hair loss
Trouble breathing
Pain in arms, legs, back, or muscles
Loss of appetite
Inflammation of the digestive tract lining
Nail changes

Lapatinib (Tykerb) serious side effects

Contact your healthcare provider immediately if you experience any of the following.

Severe diarrhea
Liver problems: yellowing of skin or whites of your eyes, dark-colored urine, right upper stomach pain or discomfort, itchy skin
Severe skin reactions: blisters on the skin, peeling skin, red skin, rash that keeps getting worse

Source: DailyMed

The following Lapatinib (Tykerb) side effects have also been reported

Along with its needed effects, a medicine 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 immediately if any of the following side effects occur:

More common

Cough

diarrhea

difficult or labored breathing

itching, skin rash

loosening of the fingernails

nosebleed

redness or soreness around the fingernails

redness, swelling, or pain of the skin

scaling of the skin on the hands and feet

tightness in the chest

tingling of the hands and feet ulceration of the skin

unusual tiredness or weakness

Rare

Chest pain

decreased urine output

dilated neck veins

extreme tiredness or weakness

irregular breathing

irregular heartbeat

swelling of the face, fingers, feet, or lower legs

weight gain

Incidence not known

Blistering, peeling, or loosening of the skin

chest discomfort

chills

clay-colored stools

dark urine

decreased appetite

difficulty with swallowing

dizziness

fainting

fast heartbeat

fever

headache

hives

irregular or slow heart rate

loss of appetite

nausea

puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue

red skin lesions, often with a purple center

red, irritated eyes

sore throat

sores, ulcers, or white spots in the mouth or on the lips

stomach pain or tenderness

swelling of the feet or lower legs

vomiting

yellow eyes or skin

Some side effects 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

Back pain

belching

cracked lips

diarrhea (mild)

difficulty in moving

discoloration of the fingernails or toenails

dry skin

heartburn

indigestion

lack or loss of strength

muscle pain or stiffness

pain in the arms or legs

stomach discomfort or upset

swelling or inflammation of the mouth

thinning of hair or hair loss

trouble sleeping

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

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Pros and cons of Lapatinib (Tykerb)

Pros

Available as pills that are swallowed once a day
Available as a lower-cost generic
A treatment option for some people who’ve tried other medications before that didn’t work

Cons

Must take 5 or 6 pills all at once each day
Not used alone to treat your breast cancer; typically taken with another anticancer medication
Requires monitoring of your liver and heart health

Pharmacist tips for Lapatinib (Tykerb)

Take lapatinib (Tykerb) at the same time every day. Take all the tablets at one time each day; don’t split them up over the course of a day.
Take your lapatinib (Tykerb) dose at least 1 hour before or 1 hour after a meal. Food can affect how much medication gets absorbed into the body, which might affect how well it works or how safe it is for you.
Avoid grapefruit and grapefruit juice while taking lapatinib (Tykerb). Grapefruit can raise the medication levels in your body and lead to a higher risk of side effects from lapatinib (Tykerb).
Make sure to stay hydrated as much as possible to avoid dehydration from possible diarrhea. During treatment, let your provider know if you get dehydrated (e.g., dry mouth, not urinating as much, lightheadedness, dizziness).
Whether you're female or male, if you're taking lapatinib (Tykerb) and you or your partner can get pregnant, use birth control during treatment and for at least 1 week after your last dose. Lapatinib (Tykerb) might cause harm to an unborn baby. Contact your provider if you or your partner becomes pregnant during this time.
It’s important to tell your provider and pharmacist about all the medications you take, including supplements and over-the-counter (OTC) medications. Certain medications can interact with lapatinib (Tykerb). Your provider can adjust your medication doses (including that of lapatinib (Tykerb)) or recommend safer alternatives.
Ask your provider or pharmacist about the best way to handle and throw away lapatinib (Tykerb) safely. Cancer medications can be very harmful to people who handle or come into contact with them.

Common questions about Lapatinib

No. Although there are many different types of breast cancer, Lapatinib is used to treat certain HER2-positive metastatic breast cancers. Your provider will perform a biopsy or surgery to help figure out the receptor type of your cancer. Knowing what type of receptor your cancer has will help them decide which treatment options to consider. Using Lapatinib also sometimes depends if you’ve tried other treatments for your cancer already. Discuss with your provider to see if Lapatinib is right for you.

It depends on your situation, so your care team will talk with you about how long you’ll need to take Lapatinib. Typically, people take Lapatinib for as long as they’re seeing benefits from the medication (preventing the cancer from growing). But if you don’t tolerate the medication well, experience certain side effects like severe diarrhea, or your provider determines the medication is causing liver or heart problems, discuss with your care team about what this means and if you should continue taking Lapatinib. Don’t stop taking Lapatinib without talking with your healthcare provider first.

If you experience diarrhea from Lapatinib, you can help manage this side effect by watching what you eat and drink. Avoid spicy and greasy foods. Eating frequent, small, bland meals can also help, but it’s best to follow this eating pattern for short periods of time since it doesn’t provide enough nutrients for your overall health. Also make sure to stay hydrated by drinking plenty of water, broth, or sports drinks each day. In addition, you can lower your risk of skin irritation around the anus by cleaning the area with warm water and letting it dry completely. Let your provider know if you develop diarrhea. They can recommend other ways to manage or treat your diarrhea, including with medications like loperamide (Imodium A-D).

Lapatinib is not a chemotherapy medication. Chemotherapy is a class of medication that kills cancer cells in your body. Lapatinib doesn’t kill cancer cells but instead slows or stops cancer cell growth.

Breastfeeding isn’t recommended while you’re taking Lapatinib. We don’t know if the medication can pass into breast milk, but it could cause serious harm to nursing infants if it does. Because of this risk, you shouldn’t breastfeed during Lapatinib treatment and for 1 week after your last dose. Talk with your provider if you have any questions about breastfeeding or other ways to feed your baby while taking Lapatinib.

Risks and warnings for Lapatinib (Tykerb)

Lapatinib (Tykerb) can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.

Liver problems

Risk factors: Severe liver problems

Warning Icon Rarely, some people taking lapatinib (Tykerb) developed liver damage, which can be severe. Liver damage can happen within days or months of starting lapatinib (Tykerb). Your provider will track your liver health through lab work while you’re taking this medication. Let your provider know if you develop any symptoms of liver problems, including yellowing of the skin or whites of your eyes, dark urine, and pain or discomfort in the right upper stomach area.

Heart problems

Risk factors: Low blood magnesium or potassium levels | Heart problems, including those affecting heart rhythm | Taking other medications that can affect your heartbeat or damage your heart

Lapatinib (Tykerb) can cause problems with your heart, such as a change in how well your heart pumps blood through your body or a change in your heartbeat. Your provider will check how well your heart is working while you’re taking this medication. They also might check your heart rhythm regularly if you’re also taking other medications that can affect your heartbeat. Tell your provider if you have trouble breathing or feel your heart pounding or racing, dizzy, lightheaded, or tired. These can be symptoms of heart problems. If they’re severe, you might need a lower dose of lapatinib (Tykerb), or you might need to stop treatment.

Diarrhea

Most people taking lapatinib (Tykerb) have diarrhea. Though severe cases aren’t common, some can be deadly. Diarrhea typically happens within the first week of starting lapatinib (Tykerb) and lasts about 5 days. If you start to have diarrhea or any changes in your bowel movement patterns, let your provider know immediately. They can recommend antidiarrheal medications like loperamide (Imodium A-D) if your diarrhea is mild. But if your diarrhea is severe, or if you have stomach cramping, nausea, or vomiting along with diarrhea, your provider will likely pause or stop your treatment.

Lung problems

Some people taking lapatinib (Tykerb) experienced lung problems like inflammation or scarring of the lungs. Contact your provider if you develop any new or worsening breathing problems like a cough that won’t go away or trouble breathing. Your provider might instruct you to stop taking lapatinib (Tykerb) while they figure out what is causing the problem.

Harm to unborn baby

Lapatinib (Tykerb) might cause harm to an unborn baby. If you’re a female who can get pregnant and you’re taking lapatinib (Tykerb), your provider might check to see if you’re pregnant before you start treatment. Make sure to use birth control while you’re receiving lapatinib (Tykerb) and for at least 1 week after your last dose. If you’re a male taking lapatinib (Tykerb) and your partner is able to become pregnant, you should also use birth control while you’re taking the medication and for at least 1 week after your last dose. Let your provider know right away if you or your partner becomes pregnant during this time.

Lapatinib (Tykerb) dosage

The average cost for 120 tablets of 250mg of Lapatinib (Tykerb) is $1,582.00 with a free GoodRx coupon. This is 78.09% off the average retail price of $7,218.88.

Tablet

Dosage	Quantity	Price as low as	Price per unit
250mg	120 tablets	$1,582.00	$13.18

Typical dosage for Lapatinib (Tykerb)

Each tablet contains 250 mg of lapatinib.

HER2-positive metastatic breast cancer: The typical dose is 5 tablets (total of 1,250 mg of lapatinib) taken by mouth at one time every day.
HR-positive, HER2-positive metastatic breast cancer: The typical dose is 6 tablets (total of 1,500 mg of lapatinib) taken by mouth at one time every day.

Your dose might be different if you have liver problems.

Interactions between Lapatinib (Tykerb) and other drugs

Lapatinib (Tykerb) may interact with certain medications or supplements. Always let your doctor and pharmacist know about any other medications or supplements (including prescribed and over-the-counter medications, vitamins, and dietary or herbal supplements) that you are currently taking. The list below does not include all possible drug interactions with Lapatinib (Tykerb). Please note that only the generic name of each medication is listed below.

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using this medicine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.

Bepridil
Cisapride
Colchicine
Dronedarone
Fluconazole
Mesoridazine
Nelfinavir
Pimozide
Piperaquine
Posaconazole
Saquinavir
Sparfloxacin
Terfenadine
Thioridazine
Ziprasidone

Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

Abametapir
Afatinib
Alfuzosin
Amiodarone
Amisulpride
Amitriptyline
Amoxapine
Anagrelide
Apomorphine
Aripiprazole
Aripiprazole Lauroxil
Arsenic Trioxide
Asenapine
Astemizole
Atazanavir
Azithromycin
Bedaquiline
Berotralstat
Betrixaban
Boceprevir
Buprenorphine
Buserelin
Capmatinib
Carbamazepine
Ceritinib
Chloroquine
Chlorpromazine
Ciprofloxacin
Citalopram
Clarithromycin
Clofazimine
Clomipramine
Clozapine
Cobicistat
Conivaptan
Crizotinib
Cyclobenzaprine
Dabigatran Etexilate
Dabrafenib
Dasabuvir
Dasatinib
Degarelix
Delamanid
Desipramine
Deslorelin
Deutetrabenazine
Dexamethasone
Digoxin
Disopyramide
Dofetilide
Dolasetron
Domperidone
Donepezil
Droperidol
Efavirenz
Encorafenib
Entrectinib
Erythromycin
Escitalopram
Fingolimod
Flecainide
Fluoxetine
Formoterol
Foscarnet
Fosnetupitant
Fosphenytoin
Fostemsavir
Gatifloxacin
Gemifloxacin
Glasdegib
Gonadorelin
Goserelin
Granisetron
Halofantrine
Haloperidol
Histrelin
Hydroxychloroquine
Hydroxyzine
Ibutilide
Idelalisib
Iloperidone
Imipramine
Indinavir
Inotuzumab Ozogamicin
Itraconazole
Ivabradine
Ivosidenib
Ketoconazole
Lasmiditan
Lefamulin
Lenvatinib
Levofloxacin
Lofexidine
Lopinavir
Lumefantrine
Macimorelin
Mefloquine
Methadone
Metronidazole
Mifepristone
Mirtazapine
Moxifloxacin
Nafarelin
Nefazodone
Netupitant
Nilotinib
Norfloxacin
Nortriptyline
Octreotide
Ofloxacin
Ondansetron
Osilodrostat
Osimertinib
Oxaliplatin
Ozanimod
Paliperidone
Panobinostat
Pasireotide
Pazopanib
Pexidartinib
Phenytoin
Pimavanserin
Pitolisant
Ponesimod
Procainamide
Prochlorperazine
Promethazine
Propafenone
Protriptyline
Quetiapine
Quinidine
Quinine
Ranolazine
Relugolix
Ribociclib
Rifabutin
Rifampin
Rifapentine
Rimegepant
Ritonavir
Selpercatinib
Sertraline
Sevoflurane
Simeprevir
Siponimod
Sodium Phosphate
Sodium Phosphate, Dibasic
Sodium Phosphate, Monobasic
Solifenacin
Sorafenib
Sotalol
St John's Wort
Sulpiride
Sunitinib
Tacrolimus
Telaprevir
Telavancin
Telithromycin
Tetrabenazine
Topotecan
Toremifene
Trazodone
Triclabendazole
Trifluoperazine
Trimipramine
Triptorelin
Ubrogepant
Vandetanib
Vardenafil
Vemurafenib
Venetoclax
Vincristine
Vincristine Sulfate Liposome
Vinflunine
Voclosporin
Voriconazole
Zuclopenthixol

Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.