Iressa

Iressa has an antitumor effect by suppressing the activity of tyrosine kinase - the endings of the factor that stimulates the growth of the epidermis, which is found in most volumetric neoplasms. The effect of the drug is aimed at reducing the growth rate of the neoplasm, preventing the formation and spread of metastases, and also reducing the rate of angiogenesis and increasing the rate of apoptosis of the resulting tumor.

By preventing the growth of neoplasms, the drug also potentiates the effectiveness of hormonal, radiation and chemotherapy agents. [ 1 ]

Indications Iressa

It is used to reduce the rate of development of non-small cell malignant tumors in the bronchi and lungs, as well as metastatic lung carcinoma.

The drug is effective in oncological pathologies and resistance of pathogenic cells to the effects of chemotherapy using platinum substances.

Release form

The therapeutic agent is released in tablets of 0.25 g, 10 pieces per blister pack; there are 3 such packs inside the package.

Pharmacokinetics

Absorption.

After oral administration, absorption occurs quite slowly. Plasma Cmax values are observed over a period of 3-7 hours. [ 2 ]

Absolute bioavailability values average 59%. Food intake does not change the bioavailability of the drug. At a gastric pH level of more than 5, the bioavailability values of gefitinib decreased by 47%.

Distribution processes.

Regular intake of the drug once a day causes an increase in concentration by 2-8 times (compared to a single use). The Css level is noted after taking 7-10 portions.

The Vd values of gefitinib after reaching Css are equal to 1400 L, which indicates that Iressa is distributed extensively within tissues.

Protein synthesis (with α1-glycoprotein and serum albumin) is approximately 90%.

Exchange processes.

Gefitinib is involved in oxidative metabolism processes involving the isoenzyme CYP3A4.

The metabolic processes of gefitinib are realized in 3 ways: metabolism affecting the N-propylmorpholine subgroup, demethylation of the quinazoline part of the methoxyl subgroup, as well as the oxidative form of dephosphorylation of the phenyl group of the halogenated type.

The major degradation product detected in human plasma is O-desmethylgefitinib. It has a lower activity than gefitinib (14-fold) against epidermal growth factor-stimulated cell growth and is therefore unlikely to have a significant impact on the clinical effect of gefitinib.

Excretion.

The systemic plasma clearance of gefitinib is approximately 0.5 L per minute. The mean half-life is 41 hours. Most of the drug is excreted in the feces. Urinary excretion is less than 4% of the administered dose.

Dosing and administration

The medicine is taken orally. The tablets should be taken at the same time, without reference to food intake.

The medicine is used 1 tablet (0.25 g), 1 time per day. If you miss the next dose, you should take it at least 12 hours before the next one. You cannot take 2 tablets at once.

If the patient is unable to swallow the whole tablet, it can be dissolved in still water (0.1 l), which he drinks (or administered through a tube). To achieve the full effect, after emptying the glass, it must be washed, refilled with water, and given to the patient to drink.

People with severe diarrhea, interstitial pneumonia, signs of allergy and other side effects during therapy can take a break from taking the drug (no more than 14 days). Then the therapy is carried out in the standard mode.

• Application for children

Prescribing the drug in pediatrics is prohibited.

Use Iressa during pregnancy

Iressa should not be used during pregnancy or breastfeeding.

Contraindications

It is contraindicated to use the medicine if you are allergic to any of the ingredients in its composition.

Caution is required in the presence of the following concomitant diseases: pneumoconiosis, idiopathic pulmonary fibrosis, increased liver enzymes and bilirubin, and hereditary hypolactasia. In case of drug-induced, interstitial or radiation pneumonia, therapy should be performed under supervision.

Side effects Iressa

Often, the use of the drug causes the following side effects: dehydration, stomatitis, diarrhea, dry mucous membranes and epidermis, as well as itching and rashes (acne or pustular). In addition, nausea, asthenia, anorexia, vomiting, a tendency to bleeding (from the nose or hematuria), conjunctivitis, xerophthalmia, blepharitis, increased activity of AST with ALT, interstitial pneumonia (if the increase in manifestations is ignored, death is possible), hyperthermia and changes in the shape of the nails occur. Iressa affects some tests: the urinary protein level and the blood creatinine and bilirubin levels increase.

Rarely, when using the drug, pancreatitis, TEN, hepatitis, hypocoagulation, urticaria, Quincke's edema, MEE or malignant form of exudative erythema, treatable erosion in the cornea, eyelash growth disorder, epidermal vasculitis and liver failure occur.

Overdose

In case of overdose, severe digestive dysfunctions, epidermal rashes and increased intensity of side effects are observed.

Interactions with other drugs

Taking the drug together with inducers of the production of the isoenzyme CYP3A4 (rifampicin, carbamazepine, barbiturates and phenytoin with St. John's wort tincture) significantly weakens the medicinal effect of gefitinib.

The effect of Iressa is potentiated by 80% when administered with inhibitors of the CYP3A4 isoenzyme (eg, itraconazole).

The risk of developing neutropenia increases when combined with vinorelbine.

In case of an increase in the gastric pH index under the influence of certain drugs, the activity of the drug is weakened by 45-50%.

Use in combination with anticoagulants increases the likelihood of bleeding. These drugs should be combined with monitoring of blood coagulation parameters.

Storage conditions

Iressa should be stored at temperatures no higher than 30°C.

Shelf life

Iressa can be used within a 4-year period from the date of manufacture of the pharmaceutical product.