Does Fasting Fog Your Brain or Sharpen It? The Data Might Surprise You
November 5, 2025
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Brand Name :
Tykerb
(United States) [Available]Synonyms :
Lapatinib
Class :
Antineoplastics, Anti-HER2; Tyrosine Kinase Inhibitor; EGFR Inhibitor
Brand Name :
Tykerb
(United States) [Available]Synonyms :
Lapatinib
Class :
Antineoplastics, Anti-HER2; Tyrosine Kinase Inhibitor; EGFR Inhibitor
Dosage Forms & Strengths:   Â
TabletÂ
250 mgÂ
Â
Metastatic Breast Cancer i.e., HER2-overexpressing
1250 mg per day should be given orally from 1st to 21st day along with capecitabine on 1st to 14th day, repeatedly in a 21-day cycle
HER2-positive advanced breast cancer:
1500 mg orally each day in combination with 2.5 mg lapatinib orally each day
Dose modifications:
Diarrhea
In case of Grade 3 diarrhea interrupt the dosing
Other toxicities
In case of Grade 2 or more toxicity interrupt the dosing
It is not safe to administer lapatinib in the pediatric populationÂ
Refer to the adult dosing
lapatinib increases the effect of flibanserin by altering the intestinal or hepatic CYP3A4 enzyme metabolism
lefamulin increases the effect of lapatinib by altering the intestinal or hepatic CYP3A4 enzyme metabolism
lomitapide increases the effect of lapatinib by altering the intestinal or hepatic CYP3A4 enzyme metabolism
lapatinib increases the effect of lonafarnib by altering the intestinal or hepatic CYP3A4 enzyme metabolism
the level of pimozide is increased by lapatinib by decreasing the metabolism
may increase the QTc prolonging effect of QT-prolonging agents
abametapir increases the effect of lapatinib by altering the intestinal or hepatic CYP3A4 enzyme metabolism
with the help of the P-glycoprotein MDR1 efflux transporter, lapatinib increases the effect of afatinib
alpelisib and lapatinib will increase the effect of each other when used simultaneously
both lapatinib and amiodarone increase the QTc interval
both lapatinib and amisulpride increase the QTc level
apalutamide decreases the effect of lapatinib by altering the intestinal or hepatic CYP3A4 enzyme metabolism
both lapatinib and arsenic trioxide increase the QTc interval
both lapatinib and artemether increase the QTc interval
avapritinib increases the effect of lapatinib by altering the intestinal or hepatic CYP3A4 enzyme metabolism
axitinib increases the effect of lapatinib by altering the intestinal or hepatic CYP3A4 enzyme metabolism
lapatinib increases the effect of bosutinib by altering the intestinal or hepatic CYP3A4 enzyme metabolism
carbamazepine decreases the effect of lapatinib by altering the intestinal or hepatic CYP3A4 enzyme metabolism
both lapatinib and ceritinib increase the QTc interval
chloramphenicol increases the effect of lapatinib by altering the intestinal or hepatic CYP3A4 enzyme metabolism
clarithromycin increases the effect of lapatinib by altering the intestinal or hepatic CYP3A4 enzyme metabolism
cobicistat increases the effect of lapatinib by altering the intestinal or hepatic CYP3A4 enzyme metabolism
lapatinib increases the effect of cobimetinib by altering the intestinal or hepatic CYP3A4 enzyme metabolism
colchicine and lapatinib increase the effect of each other when used simultaneously
darolutamide and lapatinib increase the effect of each other when used simultaneously
both lapatinib and desflurane increase the QTc interval
lapatinib increases the effect of dihydroergotamine by altering the intestinal or hepatic CYP3A4 enzyme metabolism
dihydroergotamine intranasal increases the effect of lapatinib by altering the intestinal or hepatic CYP3A4 enzyme metabolism
both lapatinib and disopyramide increase the QTc interval
lapatinib increases the effect of dronedarone by altering the intestinal or hepatic CYP3A4 enzyme metabolism
lapatinib increases the level of effectiveness of edoxaban through P-glycoprotein MDR1 efflux transporter
lapatinib increases the effect of eliglustat by altering the intestinal or hepatic CYP3A4 enzyme metabolism
both lapatinib and encorafenib increase the QTc interval
lapatinib increases the effect of entrectinib by altering the intestinal or hepatic CYP3A4 enzyme metabolism
enzalutamide decreases the effect of lapatinib by altering the intestinal or hepatic CYP3A4 enzyme metabolism
erdafitinib increases the effect of lapatinib with the help of P-glycoprotein MDR1 efflux transporter
lapatinib increases the effect of ergotamine by altering the intestinal or hepatic CYP3A4 enzyme metabolism
both lapatinib and eribulin increase the QTc interval
erythromycin base increases the effect of lapatinib by altering the intestinal or hepatic CYP3A4 enzyme metabolism
erythromycin ethyl succinate increases the effect of lapatinib by altering the intestinal or hepatic CYP3A4 enzyme metabolism
erythromycin lactobionate increases the effect of lapatinib by altering the intestinal or hepatic CYP3A4 enzyme metabolism
erythromycin stearate increases the effect of lapatinib by altering the intestinal or hepatic CYP3A4 enzyme metabolism
everolimus increases the effect of lapatinib by altering the intestinal or hepatic CYP3A4 enzyme metabolism
fentanyl increases the effect of lapatinib by altering the intestinal or hepatic CYP3A4 enzyme metabolism
fentanyl intranasal increases the effect of lapatinib by altering the intestinal or hepatic CYP3A4 enzyme metabolism
fentanyl transdermal increases the effect of lapatinib by altering the intestinal or hepatic CYP3A4 enzyme metabolism
fentanyl transmucosal increases the effect of lapatinib by altering the intestinal or hepatic CYP3A4 enzyme metabolism
both lapatinib and fexinidazole increase the QTc interval
both lapatinib and gilteritinib increase the QTc interval
both lapatinib and glasdegib increase the QTc interval
both lapatinib and hydroxychloroquine sulfate increase the QTc interval
both lapatinib and ibutilide increase the QTc interval
idelalisib increases the effect of lapatinib by altering the intestinal or hepatic CYP3A4 enzyme metabolism
both lapatinib and indapamide increase the QTc interval
lapatinib increases the effect of infigratinib by altering the intestinal or hepatic CYP3A4 enzyme metabolism
both lapatinib and inotuzumab increase the QTc interval
both lapatinib and isoflurane increase the QTc interval
itraconazole increases the effect of lapatinib by altering the intestinal or hepatic CYP3A4 enzyme metabolism
ivabradine increases the effect of lapatinib by altering the intestinal or hepatic CYP3A4 enzyme metabolism
both lapatinib and ivosidenib increase the QTc interval
ketoconazole increases the effect of lapatinib by altering the intestinal or hepatic CYP3A4 enzyme metabolism
lasmiditan, when taken with lapatinib, simultaneously increases the effect of one another
lemborexant increases the effect of lapatinib by altering the intestinal or hepatic CYP3A4 enzyme metabolism
levoketoconazole increases the effect of lapatinib by altering the intestinal or hepatic CYP3A4 enzyme metabolism
lopinavir increases the effect of lapatinib by altering the intestinal or hepatic CYP3A4 enzyme metabolism
lovastatin increases the effect of lapatinib by altering the intestinal or hepatic CYP3A4 enzyme metabolism
lurbinectedin increases the effect of lapatinib by altering the intestinal or hepatic CYP3A4 enzyme metabolism
both lapatinib and macimorelin increase the QTc interval
midazolam intranasal increases the effect of lapatinib by altering the intestinal or hepatic CYP3A4 enzyme metabolism
lapatinib increases the effect of mobocertinib by altering the intestinal or hepatic CYP3A4 enzyme metabolism
naloxegol increases the effect of lapatinib by altering the intestinal or hepatic CYP3A4 enzyme metabolism
nefazodone increases the effect of lapatinib by altering the intestinal or hepatic CYP3A4 enzyme metabolism
neratinib increases the effect of lapatinib by altering the intestinal or hepatic CYP3A4 enzyme metabolism
lapatinib increases the effect of olaparib by altering the intestinal or hepatic CYP3A4 enzyme metabolism
both lapatinib and ondansetron increase the QTc interval
lapatinib and ozanimod increase the toxicity of one another when used simultaneously
lapatinib increases the effect of pacritinib by altering the intestinal or hepatic CYP3A4 enzyme metabolism
lapatinib and palifermin increase the toxicity of one another when used simultaneously
both lapatinib and panobinostat increase the QTc interval
lapatinib increases the effect of pazopanib by altering the intestinal or hepatic CYP3A4 enzyme metabolism
lapatinib increases the effect of ranolazine by altering the intestinal or hepatic CYP3A4 enzyme metabolism
both lapatinib and ribociclib increase the QTc interval
ritonavir increases the effect of lapatinib by altering the intestinal or hepatic CYP3A4 enzyme metabolism
saquinavir increases the effect of lapatinib by altering the intestinal or hepatic CYP3A4 enzyme metabolism
selumetinib increases the effect of lapatinib by altering the intestinal or hepatic CYP3A4 enzyme metabolism
both lapatinib and sevoflurane increase the QTc interval
lapatinib increases the effect of silodosin by altering the intestinal or hepatic CYP3A4 enzyme metabolism
both lapatinib and sotalol increase the QTc interval
lapatinib and talazoparib increase the toxicity of one another when used simultaneously
lapatinib increases the effect of tazemetostat by altering the intestinal or hepatic CYP3A4 enzyme metabolism
lapatinib increases the effect of tipranavir by altering the intestinal or hepatic CYP3A4 enzyme metabolism
lapatinib increases the effect of tucatinib by altering the intestinal or hepatic CYP3A4 enzyme metabolism
It may enhance the effect when combined with pemigatinib by affecting CYP3A4 metabolism
when both drugs are combined, there may be a decreased metabolism of alpelisib   
CYP3A strong enhancers of the small intestine may reduce the bioavailability of lapatinib
lapatinib and gilteritinib, when used in combination, increase the QTc interval
dexamethasone decreases the concentration of lapatinib in serum
may increase the level of effectiveness through P-glycoprotein MDR1 efflux transporter
both lapatinib and albuterol increase the QTc interval
lapatinib increases the effect of bexarotene by altering the intestinal or hepatic CYP3A4 enzyme metabolism
cenobamate decreases the effect of lapatinib by altering the intestinal or hepatic CYP3A4 enzyme metabolism
darifenacin increases the effect of lapatinib by altering the intestinal or hepatic CYP3A4 enzyme metabolism
lapatinib increases the effect of erlotinib by altering the intestinal or hepatic CYP3A4 enzyme metabolism
both lapatinib and fluphenazine increase the QTc interval
metronidazole increases the effect of lapatinib by altering the intestinal or hepatic CYP3A4 enzyme metabolism
both lapatinib and nortriptyline increase the QTc interval
lapatinib increases the effect of ruxolitinib by altering the intestinal or hepatic CYP3A4 enzyme metabolism
both lapatinib and tropisetron increase the QTc interval
zafirlukast increases the effect of lapatinib by altering the intestinal or hepatic CYP3A4 enzyme metabolism
It may enhance the serum concentration when combined with CYP3A4 Inhibitors (Moderate)
It may enhance the serum concentration when combined with CYP3A4 Inhibitors (Moderate)
It may enhance the serum concentration when combined with CYP3A4 Inhibitors (Moderate)
It may enhance the serum concentration when combined with CYP3A4 Inhibitors (Moderate)
It may enhance the serum concentration when combined with CYP3A4 Inhibitors (Moderate)
It may diminish the effect when combined with lumateperone by affecting CYP3A4 metabolism
lapatinib: they may diminish the serum concentration of CYP3A4 Inducers
lapatinib: they may diminish the serum concentration of CYP3A4 Inducers
lapatinib: they may diminish the serum concentration of CYP3A4 Inducers
lapatinib: they may diminish the serum concentration of CYP3A4 Inducers
lapatinib: they may diminish the serum concentration of CYP3A4 Inducers
it may enhance the risk of QTc prolongation when combined with amifampridine
It may enhance the effect when combined with tafamidis meglumine
lapatinib: they may enhance the serum concentration of CYP3A inhibitors
lapatinib: they may enhance the serum concentration of CYP3A inhibitors
lapatinib: they may enhance the serum concentration of CYP3A inhibitors
lapatinib: they may enhance the serum concentration of CYP3A inhibitors
lapatinib: they may enhance the serum concentration of CYP3A inhibitors
when both drugs are combined, there may be an increased level of serum concentration of etoposide   
when both drugs are combined, there may be an increased risk or severity of QTC prolongation  
increase the therapeutic effect of daunorubicin by P-glycoprotein efflux transporter
the effect of lapatinib is decreased by lorlatinib, by altering intestinal or hepatic CYP3A4 enzyme metabolism
osimertinib and lapatinib, when used simultaneously, increase the QTc interval
increase the therapeutic effect of idarubicin by P-glycoprotein efflux transporter
may diminish the amount of P-glycoprotein (MDR1) efflux transporter
lapatinib increases the effect of amitriptyline by altering the intestinal or hepatic CYP3A4 enzyme metabolism
lapatinib increases the effect of dapsone by altering the intestinal or hepatic CYP3A4 enzyme metabolism
lapatinib increases the effect of eucalyptus by altering the intestinal or hepatic CYP3A4 enzyme metabolism
lapatinib increases the effect of isradipine by altering the intestinal or hepatic CYP3A4 enzyme metabolism
lapatinib increases the effect of loratadine by altering the intestinal or hepatic CYP3A4 enzyme metabolism
lapatinib increases the effect of parecoxib by altering the intestinal or hepatic CYP3A4 enzyme metabolism
lapatinib increases the effect of vinorelbine by altering the intestinal or hepatic CYP3A4 enzyme metabolism
when both drugs are combined, there may be an increase in QTC interval
it increases the effect or level of finasteride by altering the intestinal/hepatic enzyme CYP3A4 metabolism
it increases the effect or level of dutasteride by altering the intestinal/hepatic enzyme CYP3A4 metabolism
Actions and Spectrum:
Spectrum:
The spectrum of lapatinib includes its use in the treatment of HER2-positive breast cancer, which is a subtype of breast cancer that overexpresses the HER2 receptor. lapatinib is usually used in combination with other drugs such as trastuzumab, which is a monoclonal antibody that also targets HER2. lapatinib is also being investigated for the treatment of other types of cancer, including non-small cell lung cancer, ovarian cancer, and gastric cancer.
Adverse drug reactions:   Â
Frequency defined:   Â
>10% Â
Diarrhea Â
Anemia Â
Hand-foot synd Â
Increased LFTs Â
Nausea Â
Rash Â
Vomiting Â
Neutropenia Â
Thrombocytopenia Â
Mucositis Â
Stomatitis Â
Dyspnea Â
Dyspepsia Â
Insomnia Â
1-10%Â
LVEF decreasedÂ
InsomniaÂ
Black Box Warning:
AST and ALT are two enzymes found in the liver that are used to assess liver function. When the levels of these enzymes are elevated, it can indicate damage or inflammation in the liver. The upper limit of normal (ULN) refers to the maximum level of these enzymes that is within the normal range.
Contraindication/Caution:
Contraindications:
Pregnancy
Animal studies reveal data about the mechanism of action, where lapatinib can cause harm to an ingrowing fetus.
Breastfeeding warnings:   Â
The distribution of the drug in breast milk is unknown, but precautions are advised for potential adverse reactions.Â
Pregnancy Categories:Â
Â
Pharmacology:
lapatinib is a small molecule inhibitor that works by targeting the intracellular domain of both the epidermal growth factor receptor (EGFR) and the human epidermal growth factor receptor 2 (HER2), two important tyrosine kinase receptors that promote cell growth and division. lapatinib binds reversibly to the intracellular tyrosine kinase domain of these receptors, inhibiting their phosphorylation and downstream signaling pathways, which are responsible for cell proliferation, differentiation, and survival.
Pharmacodynamics:
The key pharmacodynamic effects of lapatinib are:
Pharmacokinetics:
AbsorptionÂ
Systemic absorption is increased by food
Peak Plasma is achieved in 4 hours
Peak plasma concentration is 2.43 mcg/mL (for 1.25 g dose)
Distribution
Protein Bound is 99%
Metabolism
Metabolized by CYP3A4 and CYP3A5
CYP3A4 and CYP2C8 enzymes help in inhibition
Excretion & EliminationÂ
Half-Life is achieved in 24 hours
The drug is excreted in feces
Administration:
lapatinib is a prescription medication that is taken orally, usually once daily. The recommended dose and duration of treatment may vary depending on the specific indication being treated and the individual patient’s condition. It is important to follow the dosing instructions provided by a healthcare provider.
lapatinib tablets should be taken at the same time every day, with or without food. The tablets should be swallowed whole, without chewing, crushing, or breaking them. If a dose is missed, it should be taken as soon as possible, but if it is almost time for the next scheduled dose, the missed dose should be skipped, and the regular dosing schedule resumed. It is important not to take a double dose of lapatinib to make up for a missed dose.
lapatinib may interact with certain medications, including some antibiotics, antifungal drugs, antidepressants, and other cancer drugs. Patients should inform their healthcare provider of all medications they are taking before starting treatment with lapatinib.
Patient information leaflet
Generic Name: lapatinib
Pronounced: la-PA-tin-ib
Why do we use lapatinib?
lapatinib is a medication that is used in the treatment of certain types of cancer, particularly breast cancer. Specifically, lapatinib is a tyrosine kinase inhibitor, which means it blocks certain enzymes that promote cancer cell growth.
lapatinib is often used in the treatment of HER2-positive breast cancer, which is a type of breast cancer that is caused by an overexpression of the HER2 protein. HER2-positive breast cancer tends to be more aggressive and fast-growing than other types of breast cancer.
lapatinib is often used in combination with other medications, such as chemotherapy, to treat HER2-positive breast cancer. It can also be used in other types of cancer, such as advanced or metastatic breast cancer, that have not responded to other treatments. Overall, lapatinib is used to slow or stop the growth of cancer cells and help prolong the life of people with cancer.
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