Trileptal (oxcarbazepine 600 mg) Dailymed

Due to physiological changes during pregnancy, plasma levels of the active metabolite of oxcarbazepine, the 10-monohydroxy derivative (MHD), may gradually decrease throughout pregnancy. It is recommended that patients be monitored carefully during pregnancy. Close monitoring should continue through the postpartum period because MHD levels may return after delivery. 



Pregnancy Exposure Registry There is a pregnancy exposure registry that monitors pregnancy outcomes in women exposed to AEDs, such as TRILEPTAL, during pregnancy. Encourage women who are taking TRILEPTAL during pregnancy to enroll in the North American Antiepileptic Drug (NAAED) Pregnancy Registry by calling 1-888-233-2334 or visiting http://www.aedpregnancyregistry.org/. Risk Summary There are no adequate data on the developmental risks associated with the use of TRILEPTAL in pregnant women; however, TRILEPTAL is closely related structurally to carbamazepine, which is considered to be teratogenic in humans. Data on a limited number of pregnancies from pregnancy registries suggest that TRILEPTAL monotherapy use is associated with congenital malformations (e.g., craniofacial defects, such as oral clefts, and cardiac malformations, such as ventricular septal defects). Increased incidences of fetal structural abnormalities and other manifestations of developmental toxicity (embryolethality, growth retardation) were observed in the offspring of animals treated with either oxcarbazepine or its active 10-hydroxy metabolite (MHD) during pregnancy at doses similar to the maximum recommended human dose (MRHD). In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively. The background risk of major birth defects and miscarriage for the indicated population is unknown. Clinical Considerations An increase in seizure frequency may occur during pregnancy because of altered levels of the active metabolite of oxcarbazepine. Monitor patients carefully during pregnancy and through the postpartum period [see Warnings and Precautions (5.10)]. Data Human Data Data from published registries have reported craniofacial defects, such as oral clefts and cardiac malformations, such as ventricular septal defects in children with prenatal oxcarbazepine exposure. Animal Data When pregnant rats were given oxcarbazepine (0, 30, 300, or 1000 mg/kg/day) orally throughout the period of organogenesis, increased incidences of fetal malformations (craniofacial, cardiovascular, and skeletal) and variations were observed at the intermediate and high doses (approximately 1.2 and 4 times, respectively, the MRHD on a mg/m2 basis). Increased embryofetal death and decreased fetal body weights were seen at the high dose. Doses ≥300 mg/kg/day were also maternally toxic (decreased body weight gain, clinical signs), but there is no evidence to suggest that teratogenicity was secondary to the maternal effects. In a study in which pregnant rabbits were orally administered MHD (0, 20, 100, or 200 mg/kg/day) during organogenesis, embryofetal mortality was increased at the highest dose (1.5 times the MRHD on a mg/m2 basis). This dose produced only minimal maternal toxicity. In a study in which female rats were dosed orally with oxcarbazepine (0, 25, 50, or 150 mg/kg/day) during the latter part of gestation and throughout the lactation period, a persistent reduction in body weights and altered behavior (decreased activity) were observed in offspring exposed to the highest dose (less than the MRHD on a mg/m2 basis). Oral administration of MHD (0, 25, 75, or 250 mg/kg/day) to rats during gestation and lactation resulted in a persistent reduction in offspring weights at the highest dose (equivalent to the MRHD on a mg/m2 basis).

Following oral administration of TRILEPTAL tablets, oxcarbazepine is completely absorbed and extensively metabolized to its pharmacologically active 10-monohydroxy metabolite (MHD). In a mass balance study in people, only 2% of total radioactivity in plasma was due to unchanged oxcarbazepine, with approximately 70% present as MHD, and the remainder attributable to minor metabolites. The half-life of the parent is about 2 hours, while the half-life of MHD is about 9 hours, so that MHD is responsible for most antiepileptic activity. Absorption Based on MHD concentrations, TRILEPTAL tablets and suspension were shown to have similar bioavailability. After single-dose administration of TRILEPTAL tablets to healthy male volunteers under fasted conditions, the median tmax was 4.5 (range, 3 to 13) hours. After single-dose administration of TRILEPTAL oral suspension to healthy male volunteers under fasted conditions, the median tmax was 6 hours. Steady-state plasma concentrations of MHD are reached within 2 to 3 days in patients when TRILEPTAL is given twice a day. At steady state the pharmacokinetics of MHD are linear and show dose proportionality over the dose range of 300 to 2400 mg/day. Food has no effect on the rate and extent of absorption of oxcarbazepine from TRILEPTAL tablets. Although not directly studied, the oral bioavailability of the TRILEPTAL suspension is unlikely to be affected under fed conditions. Therefore, TRILEPTAL tablets and suspension can be taken with or without food. Distribution The apparent volume of distribution of MHD is 49 L. Approximately 40% of MHD is bound to serum proteins, predominantly to albumin. Binding is independent of the serum concentration within the therapeutically relevant range. Oxcarbazepine and MHD do not bind to alpha-1-acid glycoprotein. Metabolism and Excretion Oxcarbazepine is rapidly reduced by cytosolic enzymes in the liver to its 10-monohydroxy metabolite, MHD, which is primarily responsible for the pharmacological effect of TRILEPTAL. MHD is metabolized further by conjugation with glucuronic acid. Minor amounts (4% of the dose) are oxidized to the pharmacologically inactive 10,11-dihydroxy metabolite (DHD). Oxcarbazepine is cleared from the body mostly in the form of metabolites which are predominantly excreted by the kidneys. More than 95% of the dose appears in the urine, with less than 1% as unchanged oxcarbazepine. Fecal excretion accounts for less than 4% of the administered dose. Approximately 80% of the dose is excreted in the urine either as glucuronides of MHD (49%) or as unchanged MHD (27%); the inactive DHD accounts for approximately 3% and conjugates of MHD and oxcarbazepine account for 13% of the dose. The half-life of the parent is about 2 hours, while the half-life of MHD is about 9 hours. Specific Populations Geriatrics Following administration of single (300 mg) and multiple (600 mg/day) doses of TRILEPTAL to elderly volunteers (60 to 82 years of age), the maximum plasma concentrations and AUC values of MHD were 30% to 60% higher than in younger volunteers (18 to 32 years of age). Comparisons of creatinine clearance in young and elderly volunteers indicate that the difference was due to age-related reductions in creatinine clearance. Pediatrics Weight-adjusted MHD clearance decreases as age and weight increases, approaching that of adults. The mean weight-adjusted clearance in children 2 years to < 4 years of age is approximately 80% higher on average than that of adults. Therefore, MHD exposure in these children is expected to be about one-half that of adults when treated with a similar weight-adjusted dose. The mean weight-adjusted clearance in children 4 to 12 years of age is approximately 40% higher on average than that of adults. Therefore, MHD exposure in these children is expected to be about three-quarters that of adults when treated with a similar weight-adjusted dose. As weight increases, for patients 13 years of age and above, the weight-adjusted MHD clearance is expected to reach that of adults. Pediatric Patients With Obesity A population PK analysis of oxcarbazepine was conducted that included n = 92 obese and non-obese pediatric patients < 18 years of age to evaluate the potential impact of obesity on plasma oxcarbazepine exposures. Obesity was defined as BMI ≥ 95th percentile for age and sex based on CDC 2000 growth chart recommendations. Simulated results from this analysis suggested that the target maintenance doses for oxcarbazepine, applied in pediatric patients ≥ 2 years of age, produced equivalent steady-state exposure of MHD between pediatric patients with and without obesity. This finding is consistent when using total body weight, or when using fat-free mass in patients ≥ 3 years and total body weight in patients < 3 yearsin the simulations. Dosage adjustment according to obesity status is not necessary. Gender No gender-related pharmacokinetic differences have been observed in children, adults, or the elderly. Race No specific studies have been conducted to assess what effect, if any, race may have on the disposition of oxcarbazepine. Renal Impairment There is a linear correlation between creatinine clearance and the renal clearance of MHD. When TRILEPTAL is administered as a single 300 mg dose in renally-impaired patients (creatinine clearance < 30 mL/min), the elimination half-life of MHD is prolonged to 19 hours, with a 2-fold increase in AUC [see Dosage and Administration (2. 7 ) and Use in Specific Populations (8.6)]. Hepatic Impairment The pharmacokinetics and metabolism of oxcarbazepine and MHD were evaluated in healthy volunteers and hepatically-impaired subjects after a single 900-mg oral dose. Mild-to-moderate hepatic impairment did not affect the pharmacokinetics of oxcarbazepine and MHD [see Dosage and Administration (2. 8 )]. Pregnancy Due to physiological changes during pregnancy, MHD plasma levels may gradually decrease throughout pregnancy [see Use in Specific Populations (8.1)]. Drug Interactions: In Vitro Oxcarbazepine can inhibit CYP2C19 and induce CYP3A4/5 with potentially important effects on plasma concentrations of other drugs. In addition, several AEDs that are cytochrome P450 inducers can decrease plasma concentrations of oxcarbazepine and MHD. No autoinduction has been observed with TRILEPTAL. Oxcarbazepine was evaluated in human liver microsomes to determine its capacity to inhibit the major cytochrome P450 enzymes responsible for the metabolism of other drugs. Results demonstrate that oxcarbazepine and its pharmacologically active 10-monohydroxy metabolite (MHD) have little or no capacity to function as inhibitors for most of the human cytochrome P450 enzymes evaluated (CYP1A2, CYP2A6, CYP2C9, CYP2D6, CYP2E1, CYP4A9, and CYP4A11) with the exception of CYP2C19 and CYP3A4/5. Although inhibition of CYP3A4/5 by oxcarbazepine and MHD did occur at high concentrations, it is not likely to be of clinical significance. The inhibition of CYP2C19 by oxcarbazepine and MHD can cause increased plasma concentrations of drugs that are substrates of CYP2C19, which is clinically relevant. In vitro, the UDP-glucuronyl transferase level was increased, indicating induction of this enzyme. Increases of 22% with MHD and 47% with oxcarbazepine were observed. As MHD, the predominant plasma substrate, is only a weak inducer of UDP-glucuronyl transferase, it is unlikely to have an effect on drugs that are mainly eliminated by conjugation through UDP-glucuronyl transferase (e.g., valproic acid, lamotrigine). In addition, oxcarbazepine and MHD induce a subgroup of the cytochrome P450 3A family (CYP3A4 and CYP3A5) responsible for the metabolism of dihydropyridine calcium antagonists, oral contraceptives and cyclosporine resulting in a lower plasma concentration of these drugs. As binding of MHD to plasma proteins is low (40%), clinically significant interactions with other drugs through competition for protein binding sites are unlikely. In Vivo Other Antiepileptic Drugs Potential interactions between TRILEPTAL and other AEDs were assessed in clinical studies. The effect of these interactions on mean AUCs and Cmin are summarized in Table 7 [see Drug Interactions (7.1, 7.2)]. Table 7: Summary of Antiepileptic Drug Interactions With TRILEPTAL Abbreviations: AED, antiepileptic drugs; CI, confidence interval; MHD, 10-monohydroxy derivative. 1nc denotes a mean change of less than 10%. 2Pediatrics. 3Mean increase in adults at high TRILEPTAL doses. AEDcoadministered Dose of AED (mg/day) TRILEPTAL dose (mg/day) Influence of TRILEPTAL on AED concentration (mean change, 90% confidence interval) Influence of AED on MHD concentration (mean change, 90% confidence interval) Carbamazepine 400-2000 900 nc1 40% decrease [CI: 17% decrease, 57% decrease] Phenobarbital 100-150 600-1800 14% increase [CI: 2% increase, 24% increase] 25% decrease [CI: 12% decrease, 51% decrease] Phenytoin 250-500 600-1800 > 1200-2400 nc1,2 up to 40% increase3 [CI: 12% increase, 60% increase] 30% decrease [CI: 3% decrease, 48% decrease] Valproic acid 400-2800 600-1800 nc1 18% decrease [CI: 13% decrease, 40% decrease] Lamotrigine 200 1200 nc1 nc1 Hormonal Contraceptives Coadministration of TRILEPTAL with an oral contraceptive has been shown to influence the plasma concentrations of the two hormonal components: ethinylestradiol (EE) and levonorgestrel (LNG) [see Drug Interactions (7.3)]. The mean AUC values of EE were decreased by 48% [90% CI: 22 to 65] in one study and 52% [90% CI: 38 to 52] in another study. The mean AUC values of LNG were decreased by 32% [90% CI: 20 to 45] in one study and 52% [90% CI: 42 to 52] in another study. Other Drug Interactions Calcium Antagonists: After repeated coadministration of TRILEPTAL, the AUC of felodipine was lowered by 28% [90% CI: 20 to 33]. Verapamil produced a decrease of 20% [90% CI: 18 to 27] of the plasma levels of MHD. Cimetidine, erythromycin and dextropropoxyphene had no effect on the pharmacokinetics of MHD. Results with warfarin show no evidence of interaction with either single or repeated doses of TRILEPTAL.