Sulthiame add-on therapy for epilepsy

BACKGROUND

This is an updated version of the Cochrane Review previously published in the Cochrane Database of Systematic Reviews 2015, Issue 10. Epilepsy is a common neurological condition, characterised by recurrent seizures. Most people respond to conventional antiepileptic drugs, however, around 30% will continue to experience seizures, despite treatment with multiple antiepileptic drugs. Sulthiame, also known as sultiame, is a widely used antiepileptic drug in Europe and Israel. We present a summary of the evidence for the use of sulthiame as add-on therapy in epilepsy.

OBJECTIVES

To assess the efficacy and tolerability of sulthiame as add-on therapy for people with epilepsy of any aetiology compared with placebo or another antiepileptic drug.

SEARCH METHODS

For the latest update, we searched the Cochrane Register of Studies (CRS Web), which includes the Cochrane Epilepsy Group's Specialized Register and CENTRAL (17 January 2019), MEDLINE Ovid (1946 to January 16, 2019), ClinicalTrials.gov and the WHO ICTRP Search Portal (17 January 2019). We imposed no language restrictions. We contacted the manufacturers of sulthiame, and researchers in the field to seek any ongoing or unpublished studies.

SELECTION CRITERIA

Randomised controlled trials of add-on sulthiame, with any level of blinding (single, double or unblinded) in people of any age, with epilepsy of any aetiology.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials for inclusion, and extracted relevant data. We assessed these outcomes: (1) 50% or greater reduction in seizure frequency between baseline and end of follow-up; (2) complete cessation of seizures during follow-up; (3) mean seizure frequency; (4) time-to-treatment withdrawal; (5) adverse effects; and (6) quality of life. We used intention-to-treat for primary analyses. We presented results as risk ratios (RR) with 95% confidence intervals (CIs). However, due to the paucity of trials, we mainly conducted a narrative analysis.

MAIN RESULTS

We included one placebo-controlled trial that recruited 37 infants with newly diagnosed West syndrome. This trial was funded by DESITIN Pharma, Germany. During the study, sulthiame was given as an add-on therapy to pyridoxine. No data were reported for the outcomes: 50% or greater reduction in seizure frequency between baseline and end of follow-up; mean seizure frequency; or quality of life. For complete cessation of seizures during a nine-day follow-up period for add-on sulthiame versus placebo, the RR was 11.14 (95% CI 0.67 to 184.47; very low-certainty evidence), however, this difference was not shown to be statistically significant (P = 0.09). The number of infants experiencing one or more adverse events was not significantly different between the two treatment groups (RR 0.85, 95% CI 0.44 to 1.64; very low-certainty evidence; P = 0.63). Somnolence was more prevalent amongst infants randomised to add-on sulthiame compared to placebo, but again, the difference was not statistically significant (RR 3.40, 95% CI 0.42 to 27.59; very low-certainty evidence; P = 0.25). We were unable to conduct meaningful analysis of time-to-treatment withdrawal and adverse effects due to incomplete data.

AUTHORS' CONCLUSIONS

Sulthiame may lead to a cessation of seizures when used as an add-on therapy to pyridoxine in infants with West syndrome, however, we are very uncertain about the reliability of this finding. The included study was small and had a significant risk of bias, largely due to the lack of details regarding blinding and the incomplete reporting of outcomes. Both issues negatively impacted the certainty of the evidence. No conclusions can be drawn about the occurrence of adverse effects, change in quality of life, or mean reduction in seizure frequency. No evidence exists for the use of sulthiame as an add-on therapy in people with epilepsy outside West syndrome.Large, multi-centre randomised controlled trials are needed to inform clinical practice, if sulthiame is to be used as an add-on therapy for epilepsy.

Drug interaction considerations in the therapeutic use of carbonic anhydrase inhibitors

INTRODUCTION

Carbonic anhydrase inhibitors (CAIs) of the sulfonamide and sulfamate type are clinically used drugs as diuretics, antiglaucoma, antiepileptic, antiobesity and anti-high altitude disease agents. Anticancer agents based on CAIs are also in clinical development for the management of hypoxic, metastatic tumors. Acetazolamide, methazolamide, dichlorophenamide, dorzolamide and brinzolamide are mainly used as antiglaucoma drugs, sulthiame, topiramate and zonisamide as antiepileptic/antiobesity agents, celecoxib and polmacoxib are dual carbonic anhydrase/cycloxygenase inhibitors. Girentuximab, a monoclonal antibody and SLC-0111, a sulfonamide inhibitor, are in clinical trials as anticancer agents.

AREAS COVERED

The drug interactions with many classes of pharmacological agents are reviewed. Some of these drugs, such as acetazolamide, topiramate and celecoxib show a large number of interactions with non-steroidal anti-inflammatory drugs (NSAIDs), diuretics, antiepileptics, immunosupressants, anticholinesterase drugs, β-blockers, anesthetics, oral contraceptives, anticancer agents, antifungals, anti-mycobacterials, lithium, metformin and clopidogrel.

EXPERT OPINION

The multiple drug interactions in which CAIs are involved should be carefully considered when such drugs are used in combination with the drug classes mentioned above, as the risks of developing toxicity and serious side effects if the dosages are not adjusted are high. There are also synergistic effects between CAIs and some NSAIDs, anticancer agents and benzodiazepines for the management of cystoid macular edema, some tumor types and neuropathic pain, respectively.

Sulthiame add-on therapy for epilepsy

BACKGROUND

Epilepsy is a common neurological condition characterised by recurrent seizures. Most patients respond to conventional antiepileptic drugs, however, around 30% will continue to experience seizures despite multiple antiepileptic drugs. Sulthiame, also known as sultiame, is a widely used antiepileptic drug in Europe and Israel. We present a summary of the evidence for the use of sulthiame as add-on therapy in epilepsy.

OBJECTIVES

To compare the efficacy and side-effect profile of sulthiame as add-on therapy compared with placebo or another antiepileptic drug.

SEARCH METHODS

We searched the Cochrane Epilepsy Group's Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, ClinicalTrials.gov and the WHO ICTRP Search Portal on 11 August 2015. No language restrictions were imposed. We contacted the manufacturers of sulthiame and researchers in the field to seek any ongoing or unpublished studies.

SELECTION CRITERIA

Randomised controlled add-on trials of sulthiame in people of any age with epilepsy of any aetiology.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials for inclusion and extracted relevant data. The following outcomes were assessed: 1) reduction in seizure frequency of 50% or greater between baseline and end of follow-up; 2) complete cessation of seizures during follow-up; 3) mean seizure frequency; 4) time to treatment withdrawal; 5) adverse drug effects; and 6) quality of life scoring. Primary analyses were intention-to-treat. We present a narrative analysis.

MAIN RESULTS

We included one trial with 37 participants with a new diagnosis of West syndrome. Sulthiame was given as an add-on therapy to pyridoxine. No data were reported for outcomes 1), 3) or 6). Overall risk ratio with 95% confidence intervals (CI) for complete cessation of seizures during a nine-day follow-up period versus placebo was 0.71 (95% CI 0.53 to 0.96). Meaningful analysis of time to treatment withdrawal and adverse drug effects was not possible due to incomplete data.

AUTHORS' CONCLUSIONS

Sulthiame may lead to a cessation of seizures when used as an add-on therapy to pyridoxine in patients with West syndrome. The included study was small and had a significant risk of bias which limits the impact of the evidence. No conclusions can be drawn about the occurrence of adverse drug effects, change in quality of life or mean reduction in seizure frequency. No evidence exists for the use of sulthiame as an add-on therapy in patients with epilepsy outside West syndrome. Large, multi-centre randomized controlled trials are necessary to inform clinical practice if sulthiame is to be used as an add-on therapy for epilepsy.