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Other drug interactions Amiodarone or Verapamil: The risk of myopathy/rhabdomyolysis is increased by concomitant administration of amiodarone or verapamil (see WARNINGS, Myopathy/Rhabdomyolysis). Text Continues Below
Cholestyramine: Concomitant cholestyramine administration decreased the mean AUC of total
ezetimibe approximately 55%. The incremental LDL-C reduction due to adding VYTORIN to cholestyramine may be reduced by this interaction. Cyclosporine: Caution should be exercised when initiating VYTORIN in patients treated with cyclosporine due to increased exposure to ezetimibe. This exposure may be greater in patients with severe renal insufficiency. In patients treated with cyclosporine, the potential effects of the increased exposure to ezetimibe from concomitant use should be carefully weighed against the benefits of alterations in lipid levels provided by ezetimibe. In a pharmacokinetic study in post-renal transplant patients with mildly impaired or normal renal function (creatinine clearance of >50 mL/min), concomitant cyclosporine administration increased the mean AUC and Cmax of total ezetimibe 3.4-fold (range 2.3- to7.9-fold) and 3.9-fold (range 3.0- to 4.4-fold), respectively. In a separate study, the total ezetimibe exposure increased 12-fold in one renal transplant patient with severe renal insufficiency receiving multiple medications, including cyclosporine. (See CLINICAL PHARMACOLOGY, Drug Interactions andWARNINGS, Myopathy/Rhabdomyolysis.) Digoxin: Concomitant administration of a single dose of digoxin in healthy male volunteers receiving simvastatin resulted in a slight elevation (less than 0.3 ng/mL) in plasma digoxin concentrations compared to concomitant administration of placebo and digoxin. Patients taking digoxin should be monitored appropriately when VYTORIN is initiated. Fibrates: The safety and effectiveness of VYTORIN administered with fibrates have not been established. Fibrates may increase cholesterol excretion into the bile, leading to cholelithiasis. In a preclinical studyin dogs, ezetimibe increased cholesterol in the gallbladder bile (see ANIMAL PHARMACOLOGY). Coadministration of VYTORIN with fibrates is not recommended until use in patients is studied. (SeeWARNINGS, Myopathy/Rhabdomyolysis.) Warfarin: Simvastatin 20-40 mg/day modestly potentiated the effect of coumarin anticoagulants: The prothrombin time, reported as International Normalized Ratio (INR), increased from a baseline of 1.7 to 1.8 and from 2.6 to 3.4 in a normal volunteer study and in a hypercholesterolemic patient study, respectively. With other statins, clinically evident bleeding and/or increased prothrombin time has been reported in a few patients taking coumarin anticoagulants concomitantly. In such patients, prothrombintime should be determined before starting VYTORIN and frequently enough during early therapy to insurethat no significant alteration of prothrombin time occurs. Once a stable prothrombin time has been documented, prothrombin times can be monitored at the intervals usually recommended for patients oncoumarin anticoagulants. If the dose of VYTORIN is changed or discontinued, the same procedure should be repeated. Simvastatin therapy has not been associated with bleeding or with changes in prothrombinn time in patients not taking anticoagulants. Ezetimibe Fenofibrate: In a pharmacokinetic study, concomitant fenofibrate administration increased total ezetimibe concentrations approximately 1.5-fold. Gemfibrozil: In a pharmacokinetic study, concomitant gemfibrozil administration increased total ezetimibe concentrations approximately 1.7-fold. Simvastatin Propranolol: In healthy male volunteers there was a significant decrease in mean Cmax, but no changein AUC, for simvastatin total and active inhibitors with concomitant administration of single doses of simvastatin and propranolol. The clinical relevance of this finding is unclear. The pharmacokinetics of the enantiomers of propranolol were not affected. CNS Toxicity Optic nerve degeneration was seen in clinically normal dogs treated with simvastatin for 14 weeks at180 mg/kg/day, a dose that produced mean plasma drug levels about 12 times higher than the mean plasma drug level in humans taking 80 mg/day. A chemically similar drug in this class also produced optic nerve degeneration (Wallerian degeneration of retino geniculate fibers) in clinically normal dogs in a dose-dependent fashion starting at 60 mg/kg/day, adose that produced mean plasma drug levels about 30 times higher than the mean plasma drug level inhumans taking the highest recommended dose (as measured by total enzyme inhibitory activity). This same drug also produced vestibulo cochlear Wallerian-like degeneration and retinal ganglion cell chromatolysis in dogs treated for 14 weeks at 180 mg/kg/day, a dose that resulted in a mean plasma drug level similar to that seen with the 60 mg/kg/day dose. CNS vascular lesions, characterized by perivascular hemorrhage and edema, mononuclear cell infiltration of perivascular spaces, perivascular fibrin deposits and necrosis of small vessels were seen in dogs treated with simvastatin at a dose of 360 mg/kg/day, a dose that produced mean plasma drug levels that were about 14 times higher than the mean plasma drug levels in humans taking 80 mg/day. Similar CNS vascular lesions have been observed with several other drugs of this class.There were cataracts in female rats after two years of treatment with 50 and 100 mg/kg/day (22 and25 times the human AUC at 80 mg/day, respectively) and in dogs after three months at 90 mg/kg/day(19 times) and at two years at 50 mg/kg/day (5 times). Carcinogenesis, Mutagenesis, Impairment of Fertility VYTORIN No animal carcinogenicity or fertility studies have been conducted with the combination of ezetimibe and simvastatin. The combination of ezetimibe with simvastatin did not show evidence of mutagenicity in a microbial mutagenicity (Ames) test with Salmonella typhimurium and Escherichia coli with or without metabolic activation. No evidence of clastogenicity was observed in vitro in a chromosomal aberration assay in human peripheral blood lymphocytes with ezetimibe and simvastatin with or without metabolic activation. There was no evidence of genotoxicity at doses up to 600 mg/kg with the combination of ezetimibe and simvastatin (1:1) in the in vivo mouse micronucleus test. Ezetimibe A 104-week dietary carcinogenicity study with ezetimibe was conducted in rats at doses up to 1500 mg/kg/day (males) and 500 mg/kg/day (females) (~20 times the human exposure at 10 mg daily based on AUC0-24hr for total ezetimibe). A 104-week dietary carcinogenicity study with ezetimibe was also conducted in mice at doses up to 500 mg/kg/day (>150 times the human exposure at 10 mg daily basedon AUC0-24hr for total ezetimibe). There were no statistically significant increases in tumor incidences indrug-treated rats or mice. No evidence of mutagenicity was observed in vitro in a microbial mutagenicity (Ames) test with Salmonella typhimurium and Escherichia coli with or without metabolic activation. No evidence of clastogenicity was observed in vitro in a chromosomal aberration assay in human peripheral blood lymphocytes with or without metabolic activation. In addition, there was no evidence of genotoxicity in thein vivo mouse micronucleus test. In oral (gavage) fertility studies of ezetimibe conducted in rats, there was no evidence of reproductive toxicity at doses up to 1000 mg/kg/day in male or female rats (~7 times the human exposure at 10 mgdaily based on AUC0-24hr for total ezetimibe). Simvastatin In a 72-week carcinogenicity study, mice were administered daily doses of simvastatin of 25, 100, and 400 mg/kg body weight, which resulted in mean plasma drug levels approximately 1, 4, and 8 times higher than the mean human plasma drug level, respectively (as total inhibitory activity based on AUC) after an 80-mg oral dose. Liver carcinomas were significantly increased in high-dose females and mid- and highdose males with a maximum incidence of 90% in males. The incidence of adenomas of the liver was significantly increased in mid- and high-dose females. Drug treatment also significantly increased the incidence of lung adenomas in mid- and high-dose males and females. Adenomas of the Harderian gland(a gland of the eye of rodents) were significantly higher in high-dose mice than in controls. No evidence ofa tumorigenic effect was observed at 25 mg/kg/day. In a separate 92-week carcinogenicity study in mice at doses up to 25 mg/kg/day, no evidence of atumorigenic effect was observed (mean plasma drug levels were 1 times higher than humans given 80 mg simvastatin as measured by AUC). In a two-year study in rats at 25 mg/kg/day, there was a statistically significant increase in the incidenceof thyroid follicular adenomas in female rats exposed to approximately 11 times higher levels ofsimvastatin than in humans given 80 mg simvastatin (as measured by AUC). A second two-year rat carcinogenicity study with doses of 50 and 100 mg/kg/day produced hepatocellular adenomas and carcinomas (in female rats at both doses and in males at 100 mg/kg/day). Thyroid follicular cell adenomas were increased in males and females at both doses; thyroid follicular cellcarcinomas were increased in females at 100 mg/kg/day. The increased incidence of thyroid neoplasms appears to be consistent with findings from other HMG-CoA reductase inhibitors. These treatment levels represented plasma drug levels (AUC) of approximately 7 and 15 times (males) and 22 and 25 times(females) the mean human plasma drug exposure after an 80 milligram daily dose. No evidence of mutagenicity was observed in a microbial mutagenicity (Ames) test with or without rator mouse liver metabolic activation. In addition, no evidence of damage to genetic material was noted inan in vitro alkaline elution assay using rat hepatocytes, a V-79 mammalian cell forward mutation study, anin vitro chromosome aberration study in CHO cells, or an in vivo chromosomal aberration assay in mousebone marrow.There was decreased fertility in male rats treated with simvastatin for 34 weeks at 25 mg/kg bodyweight (4 times the maximum human exposure level, based on AUC, in patients receiving 80 mg/day);however, this effect was not observed during a subsequent fertility study in which simvastatin wasadministered at this same dose level to male rats for 11 weeks (the entire cycle of spermatogenesis (ezetimibe/simvastatin) including epididymal maturation). No microscopic changes were observed in the testes of rats from either study. At 180 mg/kg/day, (which produces exposure levels 22 times higher than those in humans taking 80 mg/day based on surface area, mg/m2), seminiferous tubule degeneration (necrosis and loss of spermatogenic epithelium) was observed. In dogs, there was drug-related testicular atrophy, decreasedspermatogenesis, spermatocytic degeneration and giant cell formation at 10 mg/kg/day, (approximately2 times the human exposure, based on AUC, at 80 mg/day). The clinical significance of these findings is unclear. Pregnancy Pregnancy Category: X See CONTRAINDICATIONS. VYTORIN As safety in pregnant women has not been established, treatment should be immediately discontinued as soon as pregnancy is recognized. VYTORIN should be administered to women of child-bearingpotential only when such patients are highly unlikely to conceive and have been informed of the potential hazards. Ezetimibe In oral (gavage) embryo-fetal development studies of ezetimibe conducted in rats and rabbits during organogenesis, there was no evidence of embryolethal effects at the doses tested (250, 500,1000 mg/kg/day). In rats, increased incidences of common fetal skeletal findings (extra pair of thoracic ribs, unossified cervical vertebral centra, shortened ribs) were observed at 1000 mg/kg/day (~10 times the human exposure at 10 mg daily based on AUC0-24hr for total ezetimibe). In rabbits treated with ezetimibe, an increased incidence of extra thoracic ribs was observed at 1000 mg/kg/day (150 times the human exposure at 10 mg daily based on AUC0-24hr for total ezetimibe). Ezetimibe crossed the placenta when pregnant rats and rabbits were given multiple oral doses. Multiple-dose studies of ezetimibe coadministered with HMG-CoA reductase inhibitors (statins) in rats and rabbits during organogenesis result in higher ezetimibe and statin exposures. Reproductive findings occur at lower doses in coadministration therapy compared to monotherapy. Simvastatin Simvastatin was not teratogenic in rats at doses of 25 mg/kg/day or in rabbits at doses up to 10 mg/kgdaily. These doses resulted in 3 times (rat) or 3 times (rabbit) the human exposure based on mg/m2surface area. However, in studies with another structurally-related HMG-CoA reductase inhibitor, skeletalmalformations were observed in rats and mice. Rare reports of congenital anomalies have been received following intrauterine exposure to HMG-CoAreductase inhibitors. In a review of approximately 100 prospectively followed pregnancies in women
exposed to simvastatin or another structurally related HMG-CoA reductase inhibitor, the incidences of congenital anomalies, spontaneous abortions and fetal deaths/stillbirths did not exceed what would be expected in the general population. The number of cases is adequate only to exclude a 3- to 4-fold increase in congenital anomalies over the background incidence. In 89% of the prospectively followed pregnancies, drug treatment was initiated prior to pregnancy and was discontinued at some point in thefirst trimester when pregnancy was identified. Labor and Delivery The effects of VYTORIN on labor and delivery in pregnant women are unknown. Nursing Mothers In rat studies, exposure to ezetimibe in nursing pups was up to half of that observed in maternalplasma. It is not known whether ezetimibe or simvastatin are excreted into human breast milk. Because asmall amount of another drug in the same class as simvastatin is excreted in human milk and because ofthe potential for serious adverse reactions in nursing infants, women who are nursing should not takeVYTORIN (see CONTRAINDICATIONS).2 Manson, J.M., Freyssinges, C., Ducrocq, M.B., Stephenson, W.P., Postmarketing Surveillance of Lovastatin and Simvastatin ExposureDuring Pregnancy, Reproductive Toxicology, 10(6):439-446, 1996. Pediatric Use VYTORIN There are insufficient data for the safe and effective use of VYTORIN in pediatric patients. (See Ezetimibe and Simvastatin below.) Ezetimibe The pharmacokinetics of ezetimibe in adolescents (10 to 18 years) have been shown to be similar to that in adults. Treatment experience with ezetimibe in the pediatric population is limited to 4 patients (9 to 17 years) with homozygous sitosterolemia and 5 patients (11 to 17 years) with HoFH. Treatment with ezetimibe in children (<10 years) is not recommended. Simvastatin Safety and effectiveness of simvastatin in patients 10-17 years of age with heterozygous familial hypercholesterolemia have been evaluated in a controlled clinical trial in adolescent boys and in girls whowere at least 1 year post-menarche. Patients treated with simvastatin had an adverse experience profile generally similar to that of patients treated with placebo. Doses greater than 40 mg have not beens tudied in this population. In this limited controlled study, there was no detectable effect on growth or sexual maturation in the adolescent boys or girls, or any effect on menstrual cycle length in girls. Adolescent females should be counseled on appropriate contraceptive methods while on therapy with simvastatin (see CONTRAINDICATIONS and PRECAUTIONS, Pregnancy). Simvastatin has not beenstudied in patients younger than 10 years of age, nor in pre-menarchal girls. Geriatric Use Of the patients who received VYTORIN in clinical studies, 792 were 65 and older (this included 176 who were 75 and older). The safety of VYTORIN was similar between these patients and younger patients. Greater sensitivity of some older individuals cannot be ruled out. (See CLINICALPHARMACOLOGY, Special Populations and ADVERSE REACTIONS.) PRECAUTIONS Information for Patients Patients should be advised about substances they should not take concomitantly with VYTORIN and be advised to report promptly unexplained muscle pain, tenderness, or weakness (see list below and WARNINGS, Myopathy/Rhabdomyolysis). Patients should also be advised to inform other physicians prescribing a new medication that they are taking VYTORIN. Hepatic Insufficiency Due to the unknown effects of the increased exposure to ezetimibe in patients with moderate or severe hepatic insufficiency, VYTORIN is not recommended in these patients. (See CLINICAL PHARMACOLOGY, Pharmacokinetics, Special Populations.) Drug Interactions (See also CLINICAL PHARMACOLOGY, Drug Interactions)
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