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.

The adverse reactions that result from LEVETIRACETAM injection use include all of those reported for LEVETIRACETAM tablets and oral solution. Equivalent doses of intravenous (IV) levetiracetam and oral levetiracetam result in equivalent Cmax, Cmin, and total systemic exposure to levetiracetam when the IV levetiracetam is administered as a 15 minute infusion. The prescriber should be aware that the adverse reaction incidence figures in the following tables, obtained when LEVETIRACETAM was added to concurrent AED therapy, cannot be used to predict the frequency of adverse experiences in the course of usual medical practice where patient characteristics and other factors may differ from those prevailing during clinical studies.Similarly, the cited frequencies cannot be directly compared with figures obtained from other clinical investigations involving different treatments, uses, or investigators. An inspection of these frequencies, however, does provide the prescriber with one basis to estimate the relative contribution of drug and non-drug factors to the adverse reaction incidences in the population studied.

Partial Onset Seizures \- In well-controlled clinical studies using LEVETIRACETAM tablets in adults with partial onset seizures, the most frequently reported adverse reactions in patients receiving LEVETIRACETAM in combination with other AEDs, not seen at an equivalent frequency among placebo-treated patients, were somnolence, asthenia, infection and dizziness. Of the most frequently reported adverse reactions in placebo-controlled studies using LEVETIRACETAM tablets in adults experienc ing partial onset seizures, asthenia, somnolence and dizziness appeared to occur predominantly during the first 4 weeks of treatment with LEVETIRACETAM.

Table 3 lists treatment-emergent adverse reactions that occurred in at least 1% of adult epilepsy patients treated with LEVETIRACETAM tablets participating in placebo-controlled studies and were numerically more common than in patients treated with placebo. In these studies, either LEVETIRACETAM or placebo was added to concurrent AED therapy. Adverse reactions were usually mild to moderate in intensity. 

Myoclonic Seizures \- Although the pattern of adverse reactions in this study seems somewhat different from that seen in patients with partial seizures, this is likely due to the much smaller number of patients in this study compared to partial seizure studies. The adverse reaction pattern for patients with JME is expected to be essentially the same as for patients with partial seizures.

In the well-controlled clinical study using LEVETIRACETAM tablets in patients with myoclonic seizures, the most frequently reported adverse reactions in patients using LEVETIRACETAM in combination with other AEDs, not seen at an equivalent frequency among placebo-treated patients, were somnolence, neck pain, and pharyngitis.

Table 4 lists treatment-emergent adverse reactions that occurred in at least 5% of juvenile myoclonic epilepsy patients experiencing myoclonic seizures treated with LEVETIRACETAM tablets and were numerically more common than in patients treated with placebo. In this study, either LEVETIRACETAM or placebo was added to concurrent AED therapy. Adverse reactions were usually mild to moderate in intensity. 

Discontinuation or Dose Reduction in Well-Controlled Clinical Studies

Partial Onset Seizures \- In well-controlled adult clinical studies using LEVETIRACETAM tablets, 15.0% of patients receiving LEVETIRACETAM and 11.6% receiving placebo either discontinued or had a dose reduction as a result of an adverse event. Table 5 lists the most common (>1%) adverse reactions that resulted in discontinuation or dose reduction and that occurred more frequently in LEVETIRACETAM-treated patients than in placebo-treated patients.

Myoclonic Seizures \- In the placebo-controlled study using LEVETIRACETAM tablets, 8.3% of patients receiving LEVETIRACETAM and 1.7% receiving placebo either discontinued or had a dose reduction as a result of an adverse event. The adverse reactions that led to discontinuation or dose reduction in the well-controlled study and that occurred more frequently in LEVETIRACETAM-treated patients than in placebo-treated patients are presented in Table 6.

This study was too small to adequately characterize the adverse reactions leading to discontinuation. It is expected that the adverse reactions that would lead to discontinuation in this population would be similar to those resulting in discontinuation in other epilepsy trials (see tables 5 - 6).

Comparison of Gender, Age and Race \- The overall adverse experience profile of LEVETIRACETAM was similar between females and males. There are insufficient data to support a statement regarding the distribution of adverse experience reports by age and race.