The following additional adverse reactions have been identified during post approval use of Imatinib mesylate tablets. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.
Infections: hepatitis B virus reactivation 1
Nervous System Disorders: cerebral edema 1
Eye Disorders: vitreous hemorrhage
Cardiac Disorders: pericarditis, cardiac tamponade 1
Vascular Disorders: thrombosis/embolism, anaphylactic shock
Respiratory, Thoracic and Mediastinal Disorders: acute respiratory failure 1 , interstitial lung disease
Gastrointestinal Disorders: ileus/intestinal obstruction, tumor hemorrhage/tumor necrosis, gastrointestinal perforation 1 [ see Warnings and Precautions (5.6) ], diverticulitis, gastric antral vascular ectasia
Skin and Subcutaneous Tissue Disorders: lichenoid keratosis, lichen planus, toxic epidermal necrolysis, palmar-plantar erythrodysesthesia syndrome, drug rash with eosinophilia and systemic symptoms (DRESS), pseudoporphyria
Musculoskeletal and Connective Tissue Disorders: avascular necrosis/hip osteonecrosis, rhabdomyolysis/myopathy, growth retardation in children, musculoskeletal pain upon treatment discontinuation (including myalgia, pain in extremity, arthalgia, bone pain)
Reproduction Disorders: hemorrhagic corpus luteum/hemorrhagic ovarian cyst
Blood and Lymphatic System Disorder s: thrombotic microangiopathy
1 Including some fatalities
Concomitant administration of imatinib mesylate tablet and strong CYP3A4 inducers may reduce total exposure of imatinib; consider alternative agents [see Clinical Pharmacology (12.3)].
Concomitant administration of imatinib mesylate tablet and strong CYP3A4 inhibitors may result in a significant imatinib exposure increase. Grapefruit juice may also increase plasma concentrations of imatinib; avoid grapefruit juice [see Clinical Pharmacology (12.3)].
Imatinib mesylate tablet will increase plasma concentration of CYP3A4 metabolized drugs (e.g., triazolo-benzodiazepines, dihydropyridine calcium channel blockers, certain HMG-CoA reductase inhibitors, etc.). Use caution when administering imatinib mesylate tablet with CYP3A4 substrates that have a narrow therapeutic window.
Because warfarin is metabolized by CYP2C9 and CYP3A4, use low-molecular weight or standard heparin instead of warfarin in patients who require anticoagulation [see Clinical Pharmacology (12.3).]
Use caution when administering imatinib mesylate tablet with CYP2D6 substrates that have a narrow therapeutic window.
Imatinib mesylate tablet can cause fetal harm when administered to a pregnant woman based on human and animal data. There are no clinical studies regarding use of Imatinib mesylate tablets in pregnant women. There have been postmarket reports of spontaneous abortions and congenital anomalies from women who have been exposed to imatinib mesylate tablets during pregnancy. Reproductive studies in rats have demonstrated that imatinib mesylate induced teratogenicity and increased incidence of congenital abnormalities following prenatal exposure to imatinib mesylate at doses equal to the highest recommended human dose of 800 mg/day based on body surface
area. Advise women to avoid pregnancy when taking imatinib mesylate tablets. If this drug is used during pregnancy, or if the patient becomes pregnant while taking this drug, apprise the patient of the potential hazard to the fetus.
The background risk of major birth defects and miscarriage for the indicated population is not known; however, in the U.S. general population, the estimated background risk of major birth defects of clinically recognized pregnancies is 2-4% and of miscarriage is 15%-20%.
In embryo-fetal development studies in rats and rabbits, pregnant animals received oral doses of imatinib mesylate up to 100 mg/kg/day and 60 mg/kg/day, respectively, during the period of organogenesis.
In rats, imatinib mesylate was teratogenic at 100 mg/kg/day (approximately equal to the maximum human dose of 800 mg/day based on body surface area), the number of fetuses with encephalocoele and exencephaly was higher than historical control values and these findings were associated with missing or underdeveloped cranial bones. Lower mean fetal body weights were associated with retarded skeletal ossifications.
In rabbits, at doses 1.5 times higher than the maximum human dose of 800 mg/day based on body surface area, no effects on the reproductive parameters with respect to implantation sites, number of live fetuses, sex ratio or fetal weight were observed. The examinations of the fetuses did not reveal any drug related morphological changes.
In a pre- and postnatal development study in rats, pregnant rats received oral doses of imatinib mesylate during gestation (organogenesis) and lactation up to 45 mg/kg/day. Five animals developed a red vaginal discharge in the 45 mg/kg/day group on Days 14 or 15 of gestation, the significance of which is unknown since all females produced viable litters and none had increased post-implantation loss. Other maternal effects noted only at the dose of 45 mg/kg/day (approximately one-half the maximum human dose of 800 mg/day based on body surface area) included an increased numbers of stillborn pups and pups dying between postpartum Days 0 and 4. In the F 1 offspring at this same dose level, mean body weights were reduced from birth until terminal sacrifice and the number of litters achieving criterion for preputial separation was slightly decreased. There were no other significant effects in developmental parameters or behavioral testing. F 1 fertility was not affected but reproductive effects were noted at 45 mg/kg/day including an increased number of resorptions and a decreased number of viable fetuses. The NOEL for both maternal animals and the F 1 generation was 15 mg/kg/day.
Imatinib and its active metabolite are excreted into human milk. Because of the potential for serious adverse reactions in breastfed infants from imatinib mesylate tablets, advise a lactating woman not to breastfeed during treatment and for 1 month after the last dose.
Based on data from 3 breastfeeding women taking imatinib mesylate tablets, the milk:plasma ratio is about 0.5 for imatinib and about 0.9 for the active metabolite. Considering the combined concentration of imatinib and active metabolite, a breastfed infant could receive up to 10% of the maternal therapeutic dose based on body weight.
Human post-marketing reports and animal studies have shown imatinib mesylate tablets to be harmful to the developing fetus. Test pregnancy status in females with reproductive potential prior to the initiation of treatment with imatinib mesylate tablets.
Advise female patients of reproductive potential to use effective contraception (methods that result in less than 1 % pregnancy rates) when using imatinib mesylate tablets during treatment and for fourteen days after stopping treatment with imatinib mesylate tablets [see Use in Specific Populations (8.1)].
The risk of infertility in females or males of reproductive potential has not been studied in humans. In a rat study, the fertility in males and females was not affected [see Nonclinical Toxicology (13)].
The safety and effectiveness of imatinib mesylate tablets have been demonstrated in pediatric patients with newly diagnosed Ph+ chronic phase CML [see Clinical Studies (14.2)]. There are no data in children under 1 year of age.
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