2.1 Recommended Dosing

For adults and adolescent patients, the recommended dosing for monotherapy and adjunctive therapy is the same; as outlined below.

Adults and Adolescents 12 Years of Age and Older Weighing 50 kg or More

Initiate treatment with a dose of 1,000 mg once daily. The once daily dosage may be adjusted in increments of 1,000 mg every 2 weeks to a maximum recommended daily dose of 3,000 mg/day once daily.

Administration

Levetiracetam extended-release tablets are administered once daily. Levetiracetam extended-release tablets should be swallowed whole. The tablets should not be chewed, broken, or crushed.

2.2 Dosage Adjustments in Adult Patients with Renal Impairment

Levetiracetam extended-release tablets dosing must be individualized according to the patient's renal function status. Recommended dosage adjustments for adults are shown in Table 1. In order to calculate the dose recommended for patients with renal impairment, creatinine clearance adjusted for body surface area must be calculated. To do this, an estimate of the patient's creatinine clearance (CLcr) in mL/min must first be calculated using the following formula:

2.3 Discontinuation of Levetiracetam Extended-Release Tablets

Avoid abrupt withdrawal from levetiracetam extended-release tablets in order to reduce the risk of increased seizure frequency and status epilepticus [see Warnings and Precautions (5.8)].

5.1 Behavioral Abnormalities and Psychotic Symptoms

Levetiracetam extended-release tablets may cause behavioral abnormalities and psychotic symptoms. Patients treated with levetiracetam extended-release tablets should be monitored for psychiatric signs and symptoms.

Behavioral abnormalities

Levetiracetam Extended-Release Tablets

A total of 7% of levetiracetam extended-release tablets-treated patients experienced non-psychotic behavioral disorders (reported as irritability and aggression) compared to 0% of placebo-treated patients. Irritability was reported in 7% of levetiracetam extended-release tablets-treated patients. Aggression was reported in 1% of levetiracetam extended-release tablets-treated patients.

No patient discontinued treatment or had a dose reduction as a result of these adverse reactions.

The number of patients exposed to levetiracetam extended-release tablets was considerably smaller than the number of patients exposed to immediate-release levetiracetam tablets in controlled trials. Therefore, certain adverse reactions observed in the immediate-release levetiracetam tablets controlled trials will likely occur in patients receiving levetiracetam extended-release tablets.

Immediate-Release Levetiracetam Tablets

A total of 13% of adult patients and 38% of pediatric patients (4 to 16 years of age) treated with immediate-release levetiracetam tablets experienced non-psychotic behavioral symptoms (reported as aggression, agitation, anger, anxiety, apathy, depersonalization, depression, emotional lability, hostility, hyperkinesias, irritability, nervousness, neurosis, and personality disorder), compared to 6% and 19% of adult and pediatric patients on placebo. A randomized, double-blind, placebo-controlled study was performed to assess the neurocognitive and behavioral effects of immediate-release levetiracetam tablets as adjunctive therapy in pediatric patients (4 to 16 years of age). An exploratory analysis suggested a worsening in aggressive behavior in patients treated with immediate-release levetiracetam tablets in that study [see Use in Specific Populations(8.4)].

A total of 1.7% of adult patients treated with immediate-release levetiracetam tablets discontinued treatment due to behavioral adverse reactions, compared to 0.2% of placebo-treated patients. The treatment dose was reduced in 0.8% of adult patients treated with immediate-release levetiracetam tablets, compared to 0.5% of placebo-treated patients. Overall, 11% of pediatric patients treated with immediate-release levetiracetam tablets experienced behavioral symptoms associated with discontinuation or dose reduction, compared to 6.2% of placebo-treated pediatric patients.

One percent of adult patients and 2% of pediatric patients (4 to 16 years of age) treated with immediate-release levetiracetam tablets experienced psychotic symptoms, compared to 0.2% and 2%, respectively, in adult and placebo-treated pediatric patients. In the controlled study that assessed the neurocognitive and behavioral effects of immediate-release levetiracetam tablets in pediatric patients 4 to 16 years of age, 1.6% levetiracetam tablets-treated patients experienced paranoia, compared to no placebo-treated patients. There were 3.1% patients treated with immediate-release levetiracetam tablets who experienced confusional state, compared to no placebo-treated patients [see Use in Specific Populations(8.4)].

Psychotic symptoms

Immediate-Release Levetiracetam Tablets

One percent of levetiracetam tablets-treated adult patients experienced psychotic symptoms compared to 0.2% of placebo-treated patients.

Two (0.3%) levetiracetam tablets-treated adult patients were hospitalized and their treatment was discontinued due to psychosis. Both events, reported as psychosis, developed within the first week of treatment and resolved within 1 to 2 weeks following treatment discontinuation. There was no difference between drug and placebo-treated patients in the incidence of pediatric patients who discontinued treatment due to psychotic and non-psychotic adverse reactions.

5.2 Suicidal Behavior and Ideation

Antiepileptic drugs (AEDs), including levetiracetam extended-release tablets, increase the risk of suicidal thoughts or behavior in patients taking these drugs for any indication. Patients treated with any AED for any indication should be monitored for the emergence or worsening of depression, suicidal thoughts or behavior, and/or any unusual changes in mood or behavior.

Pooled analyses of 199 placebo-controlled clinical trials (mono- and adjunctive therapy) of 11 different AEDs showed that patients randomized to one of the AEDs had approximately twice the risk (adjusted Relative Risk 1.8, 95% CI:1.2, 2.7) of suicidal thinking or behavior compared to patients randomized to placebo. In these trials, which had a median treatment duration of 12 weeks, the estimated incidence rate of suicidal behavior or ideation among 27,863 AED-treated patients was 0.43%, compared to 0.24% among 16,029 placebo-treated patients, representing an increase of approximately one case of suicidal thinking or behavior for every 530 patients treated. There were four suicides in drug-treated patients in the trials and none in placebo-treated patients, but the number is too small to allow any conclusion about drug effect on suicide.

The increased risk of suicidal thoughts or behavior with AEDs was observed as early as one week after starting drug treatment with AEDs and persisted for the duration of treatment assessed. Because most trials included in the analysis did not extend beyond 24 weeks, the risk of suicidal thoughts or behavior beyond 24 weeks could not be assessed.

The risk of suicidal thoughts or behavior was generally consistent among drugs in the data analyzed. The finding of increased risk with AEDs of varying mechanisms of action and across a range of indications suggests that the risk applies to all AEDs used for any indication. The risk did not vary substantially by age (5-100 years) in the clinical trials analyzed. Table 2 shows absolute and relative risk by indication for all evaluated AEDs.

The relative risk for suicidal thoughts or behavior was higher in clinical trials for epilepsy than in clinical trials for psychiatric or other conditions, but the absolute risk differences were similar for the epilepsy and psychiatric indications.

Anyone considering prescribing levetiracetam extended-release tablets or any other AED must balance the risk of suicidal thoughts or behavior with the risk of untreated illness. Epilepsy and many other illnesses for which AEDs are prescribed are themselves associated with morbidity and mortality and an increased risk of suicidal thoughts and behavior. Should suicidal thoughts and behavior emerge during treatment, the prescriber needs to consider whether the emergence of these symptoms in any given patient may be related to the illness being treated.

5.3 Somnolence and Fatigue

Levetiracetam extended-release tablets may cause somnolence and fatigue. Patients should be monitored for these signs and symptoms and advised not to drive or operate machinery until they have gained sufficient experience on levetiracetam extended-release tablets to gauge whether it adversely affects their ability to drive or operate machinery.

Somnolence

Levetiracetam Extended-Release Tablets

In the levetiracetam extended-release tablets double-blind, controlled trial in patients experiencing partial-onset seizures, 8% of levetiracetam extended-release tablets-treated patients experienced somnolence compared to 3% of placebo-treated patients.

No patient discontinued treatment or had a dose reduction as a result of these adverse reactions.

The number of patients exposed to levetiracetam extended-release tablets was considerably smaller than the number of patients exposed to immediate-release levetiracetam tablets in controlled trials. Therefore, certain adverse reactions observed in the immediate-release levetiracetam tablets controlled trials will likely occur in patients receiving levetiracetam extended-release tablets. 

Immediate-Release Levetiracetam Tablets

In controlled trials of adult patients with epilepsy experiencing partial-onset seizures, 15% of levetiracetam tablets-treated patients reported somnolence, compared to 8% of placebo-treated patients. There was no clear dose response up to 3,000 mg/day. In a study where there was no titration, about 45% of patients receiving 4,000 mg/day reported somnolence. The somnolence was considered serious in 0.3% of the levetiracetam tablets-treated patients, compared to 0% in the placebo group. About 3% of levetiracetam tablets-treated patients discontinued treatment due to somnolence, compared to 0.7% of placebo-treated patients. In 1.4% of levetiracetam tablets-treated patients and in 0.9% of placebo-treated patients the dose was reduced, while 0.3% of the treated patients were hospitalized due to somnolence.

Asthenia

Immediate-Release Levetiracetam Tablets

In controlled trials of adult patients with epilepsy experiencing partial-onset seizures, 15% of levetiracetam tablets-treated patients reported asthenia, compared to 9% of placebo-treated patients. Treatment was discontinued due to asthenia in 0.8% of levetiracetam tablets-treated patients as compared to 0.5% of placebo-treated patients. In 0.5% of levetiracetam tablets-treated patients and in 0.2% of placebo-treated patients, the dose was reduced due to asthenia.

Somnolence and asthenia occurred most frequently within the first 4 weeks of treatment.

5.4 Anaphylaxis and Angioedema

Levetiracetam extended-release tablets can cause anaphylaxis or angioedema after the first dose or at any time during treatment. Signs and symptoms in cases reported in the postmarketing setting in patients treated with levetiracetam have included hypotension, hives, rash, respiratory distress, and swelling of the face, lip, mouth, eye, tongue, throat, and feet. In some reported cases, reactions were life-threatening and required emergency treatment. If a patient develops signs or symptoms of anaphylaxis or angioedema, levetiracetam extended-release tablets should be discontinued and the patient should seek immediate medical attention. Levetiracetam extended-release tablets should be discontinued permanently if a clear alternative etiology for the reaction cannot be established [see Contraindications (4)].

5.5 Serious Dermatological Reactions

Serious dermatological reactions, including Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN), have been reported in patients treated with levetiracetam. The median time of onset is reported to be 14 to 17 days, but cases have been reported at least four months after initiation of treatment. Recurrence of the serious skin reactions following rechallenge with levetiracetam has also been reported. Levetiracetam extended-release tablets should be discontinued at the first sign of a rash, unless the rash is clearly not drug-related. If signs or symptoms suggest SJS/TEN, use of this drug should not be resumed and alternative therapy should be considered. 

5.6 Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS)/Multiorgan Hypersensitivity

Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS), also known as multiorgan hypersensitivity, has been reported in patients taking antiepileptic drugs, including levetiracetam. These events can be fatal or life-threatening, particularly if diagnosis and treatment do not occur as early as possible. DRESS typically, although not exclusively, presents with fever, rash, lymphadenopathy, and/or facial swelling, in association with other organ system involvement, such as hepatitis, nephritis, hematological abnormalities, myocarditis, or myositis, sometimes resembling an acute viral infection. Eosinophilia is often present. Because this disorder is variable in its expression, other organ systems not noted here may be involved. It is important to note that early manifestations of hypersensitivity, such as fever or lymphadenopathy, may be present even though rash is not evident. If such signs or symptoms are present, the patient should be evaluated immediately. Levetiracetam extended-release tablets should be discontinued if an alternative etiology for the signs or symptoms cannot be established [see Contraindications (4)].

5.7 Coordination Difficulties

Coordination difficulties were not observed in the levetiracetam extended-release tablets controlled trial, however, the number of patients exposed to levetiracetam extended-release tablets was considerably smaller than the number of patients exposed to immediate-release levetiracetam tablets in controlled trials. However, adverse reactions observed in the immediate-release levetiracetam tablets controlled trials may also occur in patients receiving levetiracetam extended-release tablets.

Immediate-Release Levetiracetam Tablets

A total of 3.4% of adult levetiracetam tablets-treated patients experienced coordination difficulties, (reported as either ataxia, abnormal gait, or incoordination) compared to 1.6% of placebo-treated patients. A total of 0.4% of patients in controlled trials discontinued levetiracetam tablets treatment due to ataxia, compared to 0% of placebo-treated patients. In 0.7% of levetiracetam tablets-treated patients and in 0.2% of placebo-treated patients, the dose was reduced due to coordination difficulties, while one of the levetiracetam tablets-treated patients was hospitalized due to worsening of pre-existing ataxia. These events occurred most frequently within the first 4 weeks of treatment.

Patients should be monitored for these signs and symptoms and advised not to drive or operate machinery until they have gained sufficient experience on levetiracetam tablets to gauge whether it could adversely affect their ability to drive or operate machinery.

5.8 Withdrawal Seizures

As with most antiepileptic drugs, levetiracetam extended-release tablets should generally be withdrawn gradually because of the risk of increased seizure frequency and status epilepticus. If withdrawal is needed because of a serious adverse reaction, rapid discontinuation can be considered.

5.9 Hematologic Abnormalities

Levetiracetam extended-release tablets can cause hematologic abnormalities. Hematologic abnormalities occurred in clinical trials and included decreases in white blood cell (WBC), neutrophil, and red blood cell (RBC) counts; decreases in hemoglobin and hematocrit; and increases in eosinophil counts. Cases of agranulocytosis, pancytopenia, and thrombocytopenia have also been reported in the postmarketing setting. A complete blood count is recommended in patients experiencing significant weakness, pyrexia, recurrent infections, or coagulation disorders.

In controlled trials of immediate-release levetiracetam tablets in patients experiencing partial-onset seizures, minor, but statistically significant, decreases compared to placebo in total mean RBC count (0.03 × 106/mm3), mean hemoglobin (0.09 g/dL), and mean hematocrit (0.38%), were seen in immediate-release levetiracetam tablets-treated patients.

A total of 3.2% of levetiracetam tablets-treated and 1.8% of placebo-treated patients had at least one possibly significant (≤2.8 × 109/L) decreased WBC, and 2.4% of levetiracetam tablets-treated and 1.4% of placebo-treated patients had at least one possibly significant (≤1.0 × 109/L) decreased neutrophil count. Of the levetiracetam tablets-treated patients with a low neutrophil count, all but one rose towards or to baseline with continued treatment. No patient was discontinued secondary to low neutrophil counts.

In pediatric patients (4 to <16 years of age), statistically significant decreases in WBC and neutrophil counts were seen in patients treated with immediate-release levetiracetam tablets, as compared to placebo. The mean decreases from baseline in the immediate-release levetiracetam tablets group were -0.4 × 109/L and -0.3 × 109/L, respectively, whereas there were small increases in the placebo group. A significant increase in mean relative lymphocyte counts was observed in 1.7% of patients treated with immediate-release levetiracetam tablets compared to a decrease of 4% in patients on placebo.

In the controlled pediatric trial, a possibly clinically significant abnormal low WBC value was observed in 3% of patients treated with immediate-release levetiracetam tablets, compared to no patients on placebo. However, there was no apparent difference between treatment groups with respect to neutrophil count. No patient was discontinued secondary to low WBC or neutrophil counts.

In the controlled pediatric cognitive and neuropsychological safety study, two subjects (6.1%) in the placebo group and 5 subjects (8.6%) in the immediate-release levetiracetam tablets-treated group had high eosinophil count values that were possibly clinically significant (≥10% or ≥0.7 × 109/L). 

5.10 Seizure Control During Pregnancy

Physiological changes may gradually decrease plasma levels of levetiracetam throughout pregnancy. This decrease is more pronounced during the third trimester. It is recommended that patients be monitored carefully during pregnancy. Close monitoring should continue through the postpartum period especially if the dose was changed during pregnancy.

6.1 Clinical Trials Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.

Pediatric Patients 4 Years to <16 Years

In a pooled analysis of two controlled pediatric clinical studies in children 4 to 16 years of age with partial-onset seizures [see Clinical Studies (14.3)], the adverse reactions most frequently reported with the use of immediate-release levetiracetam tablets in combination with other AEDs, and with greater frequency than in patients on placebo, were fatigue, aggression, nasal congestion, decreased appetite, and irritability.

Table 5 lists adverse reactions that occurred in at least 2% of pediatric patients treated with immediate-release levetiracetam tablets and were more common than in pediatric patients on placebo. In these studies, either immediate-release levetiracetam tablets or placebo was added to concurrent AED therapy. Adverse reactions were usually mild to moderate in intensity.

In controlled pediatric clinical studies in patients 4-16 years of age, 7% of patients treated with immediate-release levetiracetam tablets and 9% of patients on placebo discontinued as a result of an adverse event.

In addition, the following adverse reactions were seen in other controlled studies of immediate-release levetiracetam tablets: balance disorder, disturbance in attention, eczema, hyperkinesia, memory impairment, myalgia, personality disorders, pruritus, and blurred vision.

Comparison of Gender, Age and Race

There are insufficient data for levetiracetam extended-release tablets to support a statement regarding the distribution of adverse reactions by gender, age, and race.

6.2 Postmarketing Experience

The following adverse reactions have been identified during postapproval use of immediate-release levetiracetam 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.

The listing is alphabetized: abnormal liver function test, acute kidney injury, anaphylaxis, angioedema, agranulocytosis, choreoathetosis, drug reaction with eosinophilia and systemic symptoms (DRESS), dyskinesia, erythema multiforme, hepatic failure, hepatitis, hyponatremia, muscular weakness, obsessive-compulsive disorders (OCD), pancreatitis, pancytopenia (with bone marrow suppression identified in some of these cases), panic attack, thrombocytopenia, weight loss, and worsening of seizures including in patients with SCN8A mutations. Alopecia has been reported with immediate-release levetiracetam tablets use; recovery was observed in majority of cases where immediate-release levetiracetam tablets were discontinued.

8.1 Pregnancy

Pregnancy Exposure Registry

There is a pregnancy exposure registry that monitors pregnancy outcomes in women exposed to antiepileptic drugs (AEDs), including levetiracetam extended-release tablets, during pregnancy. Encourage women who are taking levetiracetam extended-release tablets 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

Prolonged experience with levetiracetam tablets in pregnant women has not identified a drug-associated risk of major birth defects or miscarriage, based on published literature, which includes data from pregnancy registries and reflects experience over two decades [see Human Data]. In animal studies, levetiracetam produced developmental toxicity (increased embryofetal and offspring mortality, increased incidences of fetal structural abnormalities, decreased embryofetal and offspring growth, neurobehavioral alterations in offspring) at doses similar to human therapeutic doses [see Animal Data].

In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2-4% and 15-20%, respectively. The background risk of major birth defects and miscarriage for the indicated population is unknown.

Clinical Considerations

Levetiracetam extended-release tablets levels may decrease during pregnancy [see Warnings and Precautions (5.10)].

Physiological changes during pregnancy may affect levetiracetam concentration. Decrease in levetiracetam plasma concentrations has been observed during pregnancy. This decrease is more pronounced during the third trimester. Dose adjustments may be necessary to maintain clinical response.

Data

Human Data

While available studies cannot definitively establish the absence of risk, data from the published literature and pregnancy registries have not established an association with levetiracetam use during pregnancy and major birth defects or miscarriage.

Animal Data

When levetiracetam (0, 400, 1,200, or 3,600 mg/kg/day) was administered orally to pregnant rats during the period of organogenesis, reduced fetal weights and increased incidence of fetal skeletal variations were observed at the highest dose tested. There was no evidence of maternal toxicity. The no-effect dose for adverse effects on embryofetal developmental in rats (1,200 mg/kg/day) is approximately 4 times the maximum recommended human dose (MRHD) of 3,000 mg on a body surface area (mg/m2) basis.

Oral administration of levetiracetam (0, 200, 600, or 1,800 mg/kg/day) to pregnant rabbits during the period of organogenesis resulted in increased embryofetal mortality and incidence of fetal skeletal variations at the mid and high dose and decreased fetal weights and increased incidence of fetal malformations at the high dose, which was associated with maternal toxicity. The no-effect dose for adverse effects on embryofetal development in rabbits (200 mg/kg/day) is approximately equivalent to the MRHD on a mg/m2 basis.

Oral administration of levetiracetam (0, 70, 350, or 1,800 mg/kg/day) to female rats throughout pregnancy and lactation led to an increased incidence of fetal skeletal variations, reduced fetal body weight, and decreased growth in offspring at the mid and high doses and increased pup mortality and neurobehavioral alterations in offspring at the highest dose tested. There was no evidence of maternal toxicity. The no-effect dose for adverse effects on pre-and postnatal development in rats (70 mg/kg/day) is less than the MRHD on a mg/m2 basis.

Oral administration of levetiracetam to rats during the latter part of gestation and throughout lactation produced no adverse developmental or maternal effects at doses of up to 1,800 mg/kg/day (6 times the MRHD on a mg/m2 basis).

8.2 Lactation

Risk Summary

Levetiracetam is excreted in human milk. There are no data on the effects of levetiracetam extended-release tablets on the breastfed infant, or the effects on milk production.

The developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for levetiracetam extended-release tablets and any potential adverse effects on the breastfed infant from levetiracetam extended-release tablets or from the underlying maternal condition.

8.4 Pediatric Use

Safety and effectiveness in patients 12 years of age and older have been established based on pharmacokinetic data in adults and adolescents using levetiracetam extended-release tablets and efficacy and safety data in controlled pediatric studies using immediate-release levetiracetam tablets [see Adverse Reactions (6.1), Clinical Pharmacology (12.3), and Clinical Studies (14.1)].

Safety and effectiveness in pediatric patients below the age of 12 have not been established.

A 3-month, randomized, double-blind, placebo-controlled study was performed to assess the neurocognitive and behavioral effects of immediate-release levetiracetam tablets as adjunctive therapy in 98 pediatric patients with inadequately controlled partial seizures, ages 4 to 16 years (levetiracetam tablets N=64; placebo N=34). The target dose of immediate-release levetiracetam tablets was 60 mg/kg/day. Neurocognitive effects were measured by the Leiter-R Attention and Memory (AM) Battery, which assesses various aspects of a child's memory and attention. Although no substantive differences were observed between the placebo- and levetiracetam tablets-treated groups in the median change from baseline in this battery, the study was not adequate to assess formal statistical non-inferiority between the drug and placebo. The Achenbach Child Behavior Checklist (CBCL/6-18), a standardized validated tool used to assess a child’s competencies and behavioral/emotional problems, was also assessed in this study. An analysis of the CBCL/6-18 indicated a worsening in aggressive behavior, one of the eight syndrome scores, in patients treated with levetiracetam tablets [see Warnings and Precautions (5.1)].

Juvenile Animal Toxicity Data

Studies of levetiracetam in juvenile rats (dosed on postnatal days 4 through 52) and dogs (dosed from postnatal weeks 3 through 7) at doses of up to 1800 mg/kg/day (approximately 7 and 24 times, respectively, the maximum recommended pediatric dose of 60 mg/kg/day on a mg/m2 basis) did not demonstrate adverse effects on postnatal development.

8.5 Geriatric Use

There were insufficient numbers of elderly subjects in controlled trials of epilepsy to adequately assess the effectiveness of levetiracetam extended-release tablets in these patients. It is expected that the safety of levetiracetam extended-release tablets in elderly patients 65 and over would be comparable to the safety observed in clinical studies of immediate-release levetiracetam tablets.

There were 347 subjects in clinical studies of immediate-release levetiracetam tablets that were 65 and over. No overall differences in safety were observed between these subjects and younger subjects. There were insufficient numbers of elderly subjects in controlled trials of epilepsy to adequately assess the effectiveness of immediate-release levetiracetam tablets in these patients.

Levetiracetam is known to be substantially excreted by the kidney, and the risk of adverse reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, care should be taken in dose selection, and it may be useful to monitor renal function [see Clinical Pharmacology (12.3)].

8.6 Renal Impairment

The effect of levetiracetam extended-release tablets on renally impaired patients was not assessed in the controlled study. However, it is expected that the effect on levetiracetam extended-release tablets-treated patients would be similar to the effect seen in controlled studies of immediate-release levetiracetam tablets. Clearance of levetiracetam is decreased in patients with renal impairment and is correlated with creatinine clearance [see Clinical Pharmacology (12.3)]. Dose adjustment is recommended for patients with impaired renal function [see Dosage and Administration (2.2)].

10.1 Signs, Symptoms and Laboratory Findings of Acute Overdosage in Humans

The signs and symptoms for levetiracetam extended-release tablets overdose are expected to be similar to those seen with immediate-release levetiracetam tablets.

The highest known dose of oral immediate-release levetiracetam tablets received in the clinical development program was 6,000 mg/day. Other than drowsiness, there were no adverse reactions in the few known cases of overdose in clinical trials. Cases of somnolence, agitation, aggression, depressed level of consciousness, respiratory depression and coma were observed with immediate-release levetiracetam tablets overdoses in postmarketing use.

10.2 Management of Overdose

There is no specific antidote for overdose with levetiracetam extended-release tablets. If indicated, elimination of unabsorbed drug should be attempted by emesis or gastric lavage; usual precautions should be observed to maintain airway. General supportive care of the patient is indicated including monitoring of vital signs and observation of the patient's clinical status. A Certified Poison Control Center should be contacted for up to date information on the management of overdose with levetiracetam extended-release tablets.

10.3 Hemodialysis

Standard hemodialysis procedures result in significant clearance of levetiracetam (approximately 50% in 4 hours) and should be considered in cases of overdose. Although hemodialysis has not been performed in the few known cases of overdose, it may be indicated by the patient's clinical state or in patients with significant renal impairment.

12.1 Mechanism of Action

The precise mechanism(s) by which levetiracetam exerts its antiepileptic effect is unknown.

A saturable and stereoselective neuronal binding site in rat brain tissue has been described for levetiracetam. Experimental data indicate that this binding site is the synaptic vesicle protein SV2A, thought to be involved in the regulation of vesicle exocytosis. Although the molecular significance of levetiracetam binding to synaptic vesicle protein SV2A is not understood, levetiracetam and related analogs showed a rank order of affinity for SV2A which correlated with the potency of their antiseizure activity in audiogenic seizure-prone mice. These findings suggest that the interaction of levetiracetam with the SV2A protein may contribute to the antiepileptic mechanism of action of the drug.

12.2 Pharmacodynamics

Effects on QTc Interval

The effects of levetiracetam extended-release tablets on QTc prolongation is expected to be the same as that of immediate-release levetiracetam tablets. The effect of immediate-release levetiracetam tablets on QTc prolongation was evaluated in a randomized, double-blind, positive-controlled (moxifloxacin 400 mg) and placebo-controlled crossover study of levetiracetam tablets (1,000 mg or 5,000 mg) in 52 healthy subjects. The upper bound of the 90% confidence interval for the largest placebo-adjusted, baseline-corrected QTc was below 10 milliseconds. Therefore, there was no evidence of significant QTc prolongation in this study.

12.3 Pharmacokinetics

13.1 Carcinogenesis, Mutagenesis, Impairment of Fertility

14.1 Levetiracetam Extended-Release Tablets in Adults

The effectiveness of levetiracetam extended-release tablets for the treatment of partial-onset seizures in adults was established in one multicenter, randomized, double-blind, placebo-controlled clinical study across 7 countries in patients who had refractory partial-onset seizures with or without secondary generalization (Study 1).

14.2 Immediate-Release Levetiracetam Tablets in Adults

The effectiveness of immediate-release levetiracetam tablets for the treatment of partial-onset seizures in adults was established in three multicenter, randomized, double-blind, placebo-controlled clinical studies in patients who had refractory partial-onset seizures with or without secondary generalization (Studies 2, 3, and 4). The tablet formulation was used in all three studies. In these studies, 904 patients were randomized to placebo, levetiracetam tablets 1,000 mg, levetiracetam tablets 2,000 mg, or levetiracetam tablets 3,000 mg/day. Patients enrolled in Study 2 or Study 3 had refractory partial-onset seizures for at least two years and had taken two or more AEDs. Patients enrolled in Study 4 had refractory partial-onset seizures for at least 1 year and had taken one AED. At the time of the study, patients were taking a stable dose regimen of at least one AED and could take a maximum of two AEDs. During the baseline period, patients had to have experienced at least two partial-onset seizures during each 4-week period. 

Study 2

Study 2 was a double-blind, placebo-controlled, parallel-group study conducted at 41 sites in the United States, comparing immediate-release levetiracetam tablets 1,000 mg/day (N=97), immediate-release levetiracetam tablets 3,000 mg/day (N=101), and placebo (N=95), given in equally divided doses twice daily. After a prospective baseline period of 12 weeks, patients in Study 2 were randomized to one of the three treatment groups described above. The 18-week treatment period consisted of a 6-week titration period, followed by a 12-week fixed dose evaluation period, during which concomitant AED regimens were held constant. The primary measure of effectiveness in Study 2 was a between-group comparison of the percent reduction in weekly partial seizure frequency relative to placebo over the entire randomized treatment period (titration + evaluation period). Secondary outcome variables included the responder rate (incidence of patients with ≥50% reduction from baseline in partial-onset seizure frequency). The results of Study 2 are displayed in Table 6.

Table 6: Reduction in Mean Over Placebo in Weekly Frequency of Partial-Onset Seizures in Study 2

	Placebo (N=95)	Immediate-release Levetiracetam Tablets 1,000 mg/day (N=97)	Immediate-release Levetiracetam Tablets 3,000 mg/day (N=101)
Percent reduction in partial seizure frequency over placebo	–	26.1%	30.1%

The percentage of patients (y-axis) who achieved ≥50% reduction from baseline in weekly partial-onset seizure frequency over the entire randomized treatment period (titration + evaluation period) within the three treatment groups (x-axis) in Study 2 is presented in Figure 1.

Figure 1: Responder Rate (≥50% Reduction From Baseline) in Study 2

Study 3

Study 3 was a double-blind, placebo-controlled, crossover study conducted at 62 centers in Europe, comparing immediate-release levetiracetam tablets 1,000 mg/day (N=106), immediate-release levetiracetam tablets 2,000 mg/day (N=105), and placebo (N=111), given in equally divided doses twice daily. 

The first period of the study (Period A) was designed to be analyzed as a parallel-group study. After a prospective baseline period of up to 12 weeks, patients in Study 3 were randomized to one of the three treatment groups described above. The 16-week treatment period consisted of the 4-week titration period followed by a 12-week fixed dose evaluation period, during which concomitant AED regimens were held constant. The primary measure of effectiveness in Study 3 was a between group comparison of the percent reduction in weekly partial seizure frequency relative to placebo over the entire randomized treatment period (titration + evaluation period). Secondary outcome variables included the responder rate (incidence of patients with ≥50% reduction from baseline in partial-onset seizure frequency). The results of the analysis of Period A are displayed in Table 7.

Table 7: Reduction in Mean Over Placebo in Weekly Frequency of Partial-Onset Seizures in Study 3: Period A

	Placebo (N=111)	Immediate-release Levetiracetam Tablets 1,000 mg/day (N=106)	Immediate-release Levetiracetam Tablets 2,000 mg/day (N=105)
Percent reduction in partial seizure frequency over placebo	–	17.1%	21.4%*

The percentage of patients (y-axis) who achieved ≥50% reduction from baseline in weekly partial-onset seizure frequency over the entire randomized treatment period (titration + evaluation period) within the three treatment groups (x-axis) in Study 3 is presented in Figure 2.

Figure 2: Responder Rate (≥50% Reduction From Baseline) in Study 3: Period A

The comparison of immediate-release levetiracetam tablets 2,000 mg/day to immediate-release levetiracetam tablets 1,000 mg/day for responder rate in Study 3 was statistically significant (P=0.02). Analysis of the trial as a cross-over study yielded similar results.

Study 4

Study 4 was a double-blind, placebo-controlled, parallel-group study conducted at 47 centers in Europe comparing immediate-release levetiracetam tablets 3,000 mg/day (N=180) and placebo (N=104) in patients with refractory partial-onset seizures, with or without secondary generalization, receiving only one concomitant AED. Study drug was given in two divided doses. After a prospective baseline period of 12 weeks, patients in Study 4 were randomized to one of two treatment groups described above. The 16-week treatment period consisted of a 4-week titration period, followed by a 12-week fixed dose evaluation period, during which concomitant AED doses were held constant. The primary measure of effectiveness in Study 4 was a between group comparison of the percent reduction in weekly seizure frequency relative to placebo over the entire randomized treatment period (titration + evaluation period). Secondary outcome variables included the responder rate (incidence of patients with ≥50% reduction from baseline in partial-onset seizure frequency). Table 8 displays the results of Study 4.

Table 8: Reduction in Mean Over Placebo in Weekly Frequency of Partial-Onset Seizures in Study 4

	Placebo (N=104)	Immediate-release Levetiracetam Tablets 3,000 mg/day (N=180)
Percent reduction in partial seizure frequency over placebo	–	23.0%

The percentage of patients (y-axis) who achieved ≥50% reduction from baseline in weekly partial-onset seizure frequency over the entire randomized treatment period (titration + evaluation period) within the two treatment groups (x-axis) in Study 4 is presented in Figure 3.

Figure 3: Responder Rate (≥50% Reduction From Baseline) In Study 4

14.3 Immediate-Release Levetiracetam Tablets in Pediatric Patients 4 Years to 16 Years

The use of levetiracetam extended-release tablets in pediatric patients 12 years of age and older is supported by Study 5, which was conducted using immediate-release levetiracetam tablets. Levetiracetam extended-release tablets are not indicated in children below 12 years of age. 

Study 5

The effectiveness of immediate-release levetiracetam tablets for the treatment of partial-onset seizures in pediatric patients was established in a multicenter, randomized double-blind, placebo-controlled study, conducted at 60 sites in North America, in children 4 to 16 years of age with partial seizures uncontrolled by standard antiepileptic drugs (Study 5). Eligible patients on a stable dose of 1-2 AEDs, who still experienced at least 4 partial-onset seizures during the 4 weeks prior to screening, as well as at least 4 partial-onset seizures in each of the two 4-week baseline periods, were randomized to receive either immediate-release levetiracetam tablets or placebo. The enrolled population included 198 patients (levetiracetam tablets N=101; placebo N=97) with refractory partial-onset seizures, with or without secondarily generalization. Study 5 consisted of an 8-week baseline period and 4-week titration period followed by a 10-week evaluation period. Dosing was initiated at a dose of 20 mg/kg/day in two divided doses. During the treatment period, the immediate-release levetiracetam tablets doses were adjusted in 20 mg/kg/day increments, at 2-week intervals to the target dose of 60 mg/kg/day. The primary measure of effectiveness in Study 5 was a between group comparison of the percent reduction in weekly partial seizure frequency relative to placebo over the entire 14-week randomized treatment period (titration + evaluation period). Secondary outcome variables included the responder rate (incidence of patients with ≥ 50% reduction from baseline in partial-onset seizure frequency per week). Table 9 displays the results of this study.

Table 9: Reduction in Mean Over Placebo in Weekly Frequency of Partial-Onset Seizures in Study 5

	Placebo (N=97)	Immediate-release Levetiracetam Tablets (N=101)
Percent reduction in partial seizure frequency over placebo	-	26.8%

The percentage of patients (y-axis) who achieved ≥ 50% reduction in weekly partial-onset seizure frequency over the entire randomized treatment period (titration + evaluation period) within the two treatment groups (x-axis) in Study 5 is presented in Figure 4.

Figure 4: Responder Rate (≥ 50% Reduction From Baseline) in Study 5

16.1 How Supplied

Levetiracetam extended-release 500 mg tablets, USP are white, oval, biconvex film-coated extended-release tablets debossed with "HH" on one side and “172” on the other side. They are supplied in white HDPE bottles as follows:

NDC 43547-345-06: bottles of 60
NDC 43547-345-50: bottles of 500

Levetiracetam extended-release 750 mg tablets, USP are white, oval, biconvex film-coated extended-release tablets debossed with "HH" on one side and “173” on the other side. They are supplied in white HDPE bottles as follows:

NDC 43547-346-06: bottles of 60
NDC 43547-346-50: bottles of 500

16.2 Storage

Store at 20°C to 25°C (68°F to 77°F); excursions permitted between 15°C and 30°C (59°F and 86°F) [see USP Controlled Room Temperature].