The following additional adverse reactions have been identified during post approval use of imatinib mesylate. 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.
Blood and Lymphatic System Disorders: thrombotic microangiopathy
Cardiac Disorders: pericarditis, cardiac tamponade1
Eye Disorders: vitreous hemorrhage
Gastrointestinal Disorders: ileus/intestinal obstruction, tumor hemorrhage/tumor necrosis, gastrointestinal perforation1 [see Warnings and Precautions (5.6) ], diverticulitis, gastric antral vascular ectasia
Infections: hepatitis B virus reactivation1
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, arthralgia, bone pain)
Nervous System Disorders: cerebral edema1
Reproduction Disorders: hemorrhagic corpus luteum/hemorrhagic ovarian cyst
Respiratory, Thoracic and Mediastinal Disorders: acute respiratory failure1 , interstitial lung disease
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
Vascular Disorders: thrombosis/embolism, anaphylactic shock
1 Including some fatalities.
Concomitant administration of imatinib mesylate and strong CYP3A4 inducers may reduce total exposure of imatinib; consider alternative agents [see Clinical Pharmacology (12.3)].
Concomitant administration of imatinib mesylate 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 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 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 with CYP2D6 substrates that have a narrow therapeutic window.
Imatinib mesylate 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 in pregnant women. There have been postmarket reports of spontaneous abortions and congenital anomalies from women who have been exposed to imatinib mesylate 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. 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 to 4% and of miscarriage is 15% to 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 F1 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. F1 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 F1 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, 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, 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 postmarketing reports and animal studies have shown imatinib mesylate to be harmful to the developing fetus. Test pregnancy status in females with reproductive potential prior to the initiation of treatment with imatinib mesylate.
Advise female patients of reproductive potential to use effective contraception (methods that result in less than 1 % pregnancy rates) when using imatinib mesylate during treatment and for fourteen days after stopping treatment with imatinib mesylate [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 have been demonstrated in pediatric patients with newly diagnosed Ph+ chronic phase CML and Ph+ ALL [see Clinical Studies (14.2, 14.4)]. There are no data in children under 1 year of age.
In the CML clinical studies, approximately 20% of patients were older than 65 years. In the study of patients with newly diagnosed CML, 6% of patients were older than 65 years. The frequency of edema was higher in patients older than 65 years as compared to younger patients; no other difference in the safety profile was observed [see Warnings and Precautions (5.1)]. The efficacy of imatinib mesylate was similar in older and younger patients.
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