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BackgroundEpilepsy is an important neurological condition and drug resistance in epilepsy is particularly common in individuals with focal seizures. In this review, we summarise the current evidence regarding a new antiepileptic drug, levetiracetam, when used as add-on treatment for controlling drug-resistant focal epilepsy. This is an update to a Cochrane Review that was originally published in 2001. ObjectivesTo evaluate the e ectiveness of levetiracetam, added on to usual care, in treating drug-resistant focal epilepsy.

The adverse effects profile of levetiracetam in epilepsy is still being fully described. We recently published a Cochrane Review evaluating the effectiveness of levetiracetam, added on to usual care, in treating drug-resistant focal epilepsy. The five most common adverse effects were reported and analysed with no scope for reporting any less common adverse effects than those. Here, we report and analyse the remaining adverse effects (including the five most common). These were (in decreasing order of frequency) somnolence; headache; asthenia; accidental injury; dizziness; infection; pharyngitis; pain; rhinitis; abdominal pain; flu syndrome; vomiting; diarrhoea; convulsion; nausea; increased cough; anorexia; upper respiratory tract infection; hostility; personality disorder; urinary tract infection; nervousness; depression; aggression; back pain; agitation; emotional liability; psychomotor hyperactivity; pyrexia; rash; ECG abnormalities; decreased appetite; nasal congestion; irritability; abnormal behaviour; epistaxis; insomnia; altered mood; anxiety; bloody urine; diplopia; dissociation; memory impairment; pruritis; increased appetite; acne; and stomach discomfort. Only somnolence and infection were significantly associated with levetiracetam. When adverse effects pertaining to infection were combined, these affected 19.7% and 15.1% of participants on levetiracetam and placebo (relative risk 1.16, CI 0.89-1.50, Chi(2) heterogeneity p = 0.13). Somnolence and infection further retained significance in adults while no single adverse effect was significant in children. This review updates the adverse effects profile data on levetiracetam use by empirically reporting its common and uncommon adverse effects and analysing their relative importance statistically using data from a group of trials that possess low Risk of Bias and high Quality of Evidence GRADE scores.