Clonazepam add-on therapy for drug-resistant epilepsy in adults and children

Review question
This review aimed to evaluate the efficacy and tolerability of clonazepam when used as an add-on therapy for adults and children with drug-resistant focal onset or generalised onset epileptic seizures, when compared with placebo or another antiepileptic agent.

Background
Epilepsy affects about 70 million people worldwide, and nearly a quarter of patients with seizures have drug-resistant epilepsy. Clonazepam is one of the 1,4-benzodiazepine drugs commonly used in epilepsy management, and recommended for second-line adjunctive treatment for various types of seizures. Previous studies have shown that clonazepam is effective in comparison with placebo when used as a supplement to existing medication for people with an insufficient response to conventional antiepileptic treatment.

Review methods
We searched different databases that contain both published and unpublished results of medical studies. We planned to include only randomised controlled studies (i.e. studies in which participants are randomly allocated to one or more treatments), which are considered the gold-standard of experimental studies in research literature. Two review authors planned to independently select studies for inclusion, extract relevant data, and assess trial quality.

Key results
We found no double-blind randomised controlled trials that considered clonazepam as an add-on therapy for adults and children with resistant focal or generalised onset epileptic seizures, thus its efficacy and tolerability could not be analysed in this review. There is a need for double-blind randomised controlled trials of clonazepam as an add-on therapy for drug-resistant epilepsy.

The evidence is current to June 2019.

Authors' conclusions: 

There is no evidence from double-blind randomised controlled trials for or against the use of clonazepam as an add-on therapy for adults and children with drug-resistant focal or generalised onset epileptic seizures. Since the last version of this review no new studies have been found.

Read the full abstract...
Background: 

This is an updated version of the original Cochrane Review published in 2018, Issue 5.

Epilepsy affects over 70 million people worldwide, and nearly a quarter of patients with seizures have drug-resistant epilepsy. People with drug-resistant epilepsy have increased risks of premature death, injuries, psychosocial dysfunction, and a reduced quality of life.

Objectives: 

To assess the efficacy and tolerability of clonazepam when used as an add-on therapy for adults and children with drug-resistant focal onset or generalised onset epileptic seizures, when compared with placebo or another antiepileptic agent.

Search strategy: 

For the latest update we searched the following databases on 4 June 2019: Cochrane Register of Studies (CRS Web), MEDLINE (Ovid) 1946 to 3 June, 2019. The Cochrane Register of Studies (CRS Web) includes the Cochrane Epilepsy Group Specialized Register, the Cochrane Central Register of Controlled Trials (CENTRAL), and randomised or quasi-randomised, controlled trials from Embase, ClinicalTrials.gov and the World Health Organization International Clinical Trials Registry Platform (ICTRP).

Selection criteria: 

Double-blind randomised controlled studies of add-on clonazepam in people with resistant focal or generalised onset seizures, with a minimum treatment period of eight weeks. The studies could be of parallel or cross-over design.

Data collection and analysis: 

Two review authors independently selected studies for inclusion, extracted relevant data, and assessed trial quality. We contacted study authors for additional information.

Main results: 

We found no double-blind randomised controlled trials which met the inclusion criteria.

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