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Brand Name :
Iressa
(United States) [Available]Synonyms :
gefitinib
Class :
Antineoplastics and EGFR Inhibitors
Brand Name :
Iressa
(United States) [Available]Synonyms :
gefitinib
Class :
Antineoplastics and EGFR Inhibitors
Dosage forms & StrengthsÂ
TabletÂ
250mg Â
gefitinib is used to treat adult patients with NSCLC metastatic non-small cell lung cancer 250 mg four times daily until the disease is reduced or unacceptable toxicity is achieved
Dose Adjustments
Permanently discontinue the medication in case of:
Severe hepatic impairment
Persistent ulcers
Gastrointestinal perforation
Interstitial lung disease
When co-administering the drug with CYP3A4 inducers, increase the dose to 500 mg orally daily
Restart the dose of 250 mg per day after the discontinuation of CYP3A4 inducer
Safety and efficacy of gefitinib are not found for pediatric dosing.Â
Refer to the adult dosingÂ
gefitinib: they may diminish the serum concentration of antacids
gefitinib: they may diminish the serum concentration of antacids
gefitinib: they may diminish the serum concentration of antacids
gefitinib: they may diminish the serum concentration of antacids
gefitinib: they may diminish the serum concentration of antacids
gefitinib: they may diminish the serum concentration of antacids
may diminish the serum concentration of Antacids
may enhance the serum concentration of each other when it is combined
may enhance the serum concentration of each other when it is combined
may enhance the serum concentration of each other when it is combined
may enhance the serum concentration of each other when it is combined
may enhance the serum concentration of each other when it is combined
may increase the level by affecting hepatic enzyme CYP3A4 metabolism
may increase the level by affecting hepatic enzyme CYP3A4 metabolism
may increase the level by affecting hepatic enzyme CYP3A4 metabolism
may increase the level by affecting hepatic enzyme CYP3A4 metabolism
abametapir increases the effect of gefitinib by altering the intestinal/ hepatic CYP3A4 enzyme metabolism
both the drugs, when used in combination, increase the effect of one another
apalutamide decreases the effect of gefitinib by altering the intestinal/ hepatic CYP3A4 enzyme metabolism
fexinidazole increases the effect of gefitinib by altering the intestinal/ hepatic CYP3A4 enzyme metabolism
ivosidenib decreases the effect of gefitinib by altering the intestinal/ hepatic CYP3A4 enzyme metabolism
both the drugs, when used in combination, increase the effect of one another
both the drugs, when used in combination, increase the effect of one another
both the drugs, when used in combination, increase the effect of one another
both the drugs, when used in combination, increase the effect of one another
tucatinib increases the effect of gefitinib by altering the intestinal/ hepatic CYP3A4 enzyme metabolism
when both drugs are combined, there may be an increased level of serum concentration of alpelisib   
CYP3A strong enhancers of the small intestine may reduce the bioavailability of gefitinib
it interacts with gefitinib by increasing the pH of the gastric cavity. It is applicable only to oral dosage forms of both drugs.
belzutifan decreases the effect of gefitinib by altering the intestinal/ hepatic CYP3A4 enzyme metabolism
bosentan decreases the effect of gefitinib by altering the intestinal/ hepatic CYP3A4 enzyme metabolism
it interacts with gefitinib by increasing the pH of the gastric cavity. It is applicable only to oral dosage forms of both the drugs
carbamazepine decreases the effect of gefitinib by altering the intestinal/ hepatic CYP3A4 enzyme metabolism
efavirenz decreases the effect of gefitinib by altering the intestinal/ hepatic CYP3A4 enzyme metabolism
etravirine decreases the effect of gefitinib by altering the intestinal/ hepatic CYP3A4 enzyme metabolism
fedratinib increases the effect of gefitinib by altering the intestinal/ hepatic CYP3A4 enzyme metabolism
fosphenytoin decreases the effect of gefitinib by altering the intestinal/ hepatic CYP3A4 enzyme metabolism
grapefruit increases the effect of gefitinib by altering the intestinal/ hepatic CYP3A4 enzyme metabolism
indinavir increases the effect of gefitinib by altering the intestinal/ hepatic CYP3A4 enzyme metabolism
ketoconazole increases the effect of gefitinib by altering the intestinal/ hepatic CYP3A4 enzyme metabolism
lorlatinib decreases the effect of gefitinib by altering the intestinal/ hepatic CYP3A4 enzyme metabolism
gefitinib increases the effect of mavacamten by altering the intestinal/ hepatic CYP3A4 enzyme metabolism
nafcillin decreases the effect of gefitinib by altering the intestinal/ hepatic CYP3A4 enzyme metabolism
oxcarbazepine decreases the effect of gefitinib by altering the intestinal/ hepatic CYP3A4 enzyme metabolism
phenytoin decreases the effect of gefitinib by altering the intestinal/ hepatic CYP3A4 enzyme metabolism
rifampin decreases the effect of gefitinib by altering the intestinal/ hepatic CYP3A4 enzyme metabolism
rifapentine decreases the effect of gefitinib by altering the intestinal/ hepatic CYP3A4 enzyme metabolism
saquinavir increases the effect of gefitinib by altering the intestinal/ hepatic CYP3A4 enzyme metabolism
tecovirimat decreases the effect of gefitinib by altering the intestinal/ hepatic CYP3A4 enzyme metabolism
gefitinib, with the help of an unspecified interaction mechanism, increases the effect of warfarin
it may enhance the metabolism when combined with oxcarbazepine
When encainide is used together with gefitinib, this leads to a reduction in the encainide’s metabolism
gefitinib: the effect of gefitinib is decreased by lorlatinib, by altering intestinal or hepatic CYP3A4 enzyme metabolism
fedratinib increases the effect of gefitinib by altering the intestinal/ hepatic CYP3A4 enzyme metabolism
idelalisib increases the effect or level of gefitinib by altering the intestinal/hepatic CYP3A4 metabolism
When gefitinib is used together with oliceridine, this leads to reduction in oliceridine’s metabolism
Actions:Â
Spectrum:Â
The spectrum of gefitinib activity is primarily in treating advanced or metastatic NSCLC with specific EGFR mutations. gefitinib is indicated for the first-line treatment of NSCLC with exon 19 deletions or exon 21 (L858R) substitution mutations in the EGFR gene. It is also indicated for the treatment of NSCLC that has progressed after prior chemotherapy, regardless of EGFR mutation status.Â
Frequency defined:Â
>10%Â
Skin reactionsÂ
DiarrheaÂ
Decreased appetiteÂ
VomitingÂ
Increased ALTÂ
1-10%Â
Increased ASTÂ
StomatitisÂ
ConjunctivitisÂ
ConjunctivitisÂ
Increased ALTÂ
Nail disordersÂ
DiarrheaÂ
Increased ASTÂ
Increased bilirubinÂ
Decreased appetiteÂ
Skin reactionsÂ
Interstitial lung diseaseÂ
VomitingÂ
<1%Â
Interstitial lung diseaseÂ
Increased bilirubinÂ
StomatitisÂ
Corneal erosion and aberrant eyelash growth Â
Nail disordersÂ
Gastrointestinal perforation Â
Ocular keratitis Â
Erythema multiforme and dermatitis bullous Â
Fatal hepatoxicity Â
Contraindication/Caution:Â
Contraindication:Â
The drug is contraindicated in patients who are hypersensitive to itÂ
Caution:Â
Pregnancy consideration: The drug is unsafe for pregnant women and the developing fetus.Â
Lactation: No data on the excretion of gefitinib in breast milk is available. Hence, potential adverse effects and potential benefits should be compared and considered.Â
Pregnancy category:Â
Â
Pharmacology:Â
gefitinib blocks the intracellular tyrosine kinase domain of EGFR, preventing the activation of downstream signaling pathways involved in tumor cell proliferation and survival. The drug binds reversibly to the ATP binding site of EGFR, inhibiting its autophosphorylation and downstream signaling. Â
Pharmacodynamics:Â
gefitinib has been shown to selectively inhibit mutant forms of EGFR found in some types of NSCLC, but it is less effective against wild-type EGFR.Â
Pharmacokinetics:Â
AbsorptionÂ
Mean oral bioavailability is 60%Â
Peak plasma concentration is achieved in 3-7 hoursÂ
Steady state achieved in 10 daysÂ
DistributionÂ
Protein-bound is 90%Â
The volume of distribution is 1400 LÂ
MetabolismÂ
The drug is extensively metabolized predominantly by CYP3A4Â
Elimination/ExcretionÂ
The half-life is 48 hoursÂ
The drug is excreted 86% in feces; and less than 4% urineÂ
Administration:Â
gefitinib is an oral medication usually administered once daily on an empty stomach. It should be taken at least 1 hour before or 2 hours after a meal. The recommended dose of gefitinib is 250 mg per day, although the HCP must adjust the dose based on individual patient factors such as age, body weight, and renal or hepatic function.Â
gefitinib tablets should be swallowed whole with water and not crushed or chewed. If a patient misses a dose, they should not take a double dose to make up for the missed one. Instead, they should take the next scheduled dose at the usual time.Â
Patient information leafletÂ
Generic Name: gefitinibÂ
Pronounced: ge-FI-ti-nibÂ
Why do we use gefitinib?Â
gefitinib is a medication used in the treatment of certain types of cancer, specifically non-small cell lung cancer (NSCLC). It belongs to a class of drugs called tyrosine kinase inhibitors (TKIs) which work by blocking the action of the epidermal growth factor receptor (EGFR) protein. Â
It is important to note that gefitinib is not a cure for cancer and may not work for everyone. The healthcare professional should decide the usage of gefitinib or any other medication for cancer treatment.Â
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