Antiepileptic drug therapy for adults: when to initiate and how to choose

Phenytoin versus levetiracetam as prophylaxis for postcraniotomy seizure in patients with no history of seizures: systematic review and meta-analysis

OBJECTIVEDe novo seizure following craniotomy (DSC) for nontraumatic pathology may adversely affect medical and neurological outcomes in patients with no history of seizures who have undergone craniotomies. Antiepileptic drugs (AEDs) are commonly used prophylactically in patients undergoing craniotomy; however, evidence supporting this practice is limited and mixed. The authors aimed to collate the available evidence on the efficacy and tolerability of levetiracetam monotherapy and compare it with that of the classic AED, phenytoin, for DSC.METHODSPubMed, Embase, Web of Science, and the Cochrane Library were searched for studies that compared levetiracetam with phenytoin for DSC prevention. Inclusion criteria were adult patients with no history of epilepsy who underwent craniotomy with prophylactic usage of phenytoin, a comparator group with levetiracetam treatment as the main treatment difference between the two groups, and availability of data on the numbers of patients and seizures for each group. Patients with brain injury and previous seizure history were excluded. DSC occurrence and adverse drug reaction (ADR) were evaluated. Seizure occurrence was calculated using the Peto odds ratio (POR), which is the relative effect estimation method of choice for binary data with rare events.RESULTSData from 7 studies involving 803 patients were included. The DSC occurrence rate was 1.26% (4/318) in the levetiracetam cohort and 6.60% (32/485) in the phenytoin cohort. Meta-analysis showed that levetiracetam is significantly superior to phenytoin for DSC prevention (POR 0.233, 95% confidence interval [CI] 0.117-0.462, p < 0.001). Subgroup analysis demonstrated that levetiracetam is superior to phenytoin for DSC due to all brain diseases (POR 0.129, 95% CI 0.039-0.423, p = 0.001) and tumor (POR 0.282, 95% CI 0.117-0.678, p = 0.005). ADRs in the levetiracetam group were cognitive disturbance, thrombophlebitis, irritability, lethargy, tiredness, and asthenia, whereas rash, anaphylaxis, arrhythmia, and hyponatremia were more common in the phenytoin group. The overall occurrence of ADR in the phenytoin (34/466) and levetiracetam (26/432) groups (p = 0.44) demonstrated no statistically significant difference in ADR occurrence. However, the discontinuation rate of AEDs due to ADR was 53/297 in the phenytoin group and 6/196 in the levetiracetam group (POR 0.266, 95% CI 0.137-0.518, p < 0.001).CONCLUSIONSLevetiracetam is superior to phenytoin for DSC prevention for nontraumatic pathology and has fewer serious ADRs that lead to discontinuation. Further high-quality studies that compare levetiracetam with placebo are necessary to provide evidence for establishing AED guidelines.

Benefits and risks of pharmacological and surgical treatments for essential tremor: disease mechanisms and current management

Essential tremor (ET) is a neurological disease (and possibly a family of diseases) whose most recognisable feature is an action tremor of the hands and occasionally of the voice and head. Current data support the view that CNS gamma-amino-butyric acid (GABA)-ergic mechanisms may underlie ET and that the tremor may be further modulated by peripheral (muscle) adrenoreceptors. Potential pharmacotherapeutic options, targeted to influence the activity of the neurotransmitter GABA within the CNS and the peripheral adrenergic receptors, are part of the current armamentarium to treat ET. As such, primidone and propranolol remain the mainstays of the therapy for ET. Intramuscular injections of botulinum toxin A may play a role in the treatment of voice and head tremor. Surgical options, which are reserved for patients with severe, medically-refractory tremor, provide adequate tremor control in the majority of patients. As with other progressive neurological disorders of late life, the ability to use neuroprotective medications to intervene in the developing disease to either slow or halt the progression of the pathological process, would involve an understanding of underlying disease mechanisms. The understanding of these mechanisms in ET is limited and further study of these mechanisms is critical for the development of such therapies.

Zonisamide: a review of its use in the management of partial seizures in epilepsy

Zonisamide (Zonegran, Excegran) is a new-generation, broad-spectrum antiepileptic drug (AED) currently approved as adjunctive therapy for the treatment of medically refractory partial seizures in adults in the US and as adjunctive therapy or monotherapy in the control of partial and generalised seizures in adults and children in Japan and Korea. Either as adjunctive therapy or monotherapy, zonisamide effectively reduces the frequency of partial seizures, with or without secondary generalisation to tonic-clonic seizures, in adults and children with epilepsy. The drug is generally well tolerated and, additionally, has a favourable pharmacokinetic profile permitting once- or twice-daily administration. Direct head-to-head comparisons with other AEDs would be beneficial in fully defining the place of zonisamide in therapy. In the meantime, adjunctive therapy or monotherapy with zonisamide is a convenient, useful option for the management of partial seizures, including those refractory to other AEDs.