Seizure control and complications in patients switching from clobazam to clonazepam due to drug shortage.

ABSTRACT

BACKGROUND: Antiseizure medication (ASM) shortages are a global problem that have a negative impact on outcomes such as seizure control in patients with epilepsy (PWE). In the case of clobazam (CLB) shortage, there is no study regarding the management strategy. This study aims to investigate the alteration in seizure frequency and the occurrence of side effects in PWE undergoing an abrupt switch from clobazam (CLB) to clonazepam (CLZ), during CLB shortage. MATERIAL AND METHODS: A retrospective study was conducted from electronic health records at our neurology outpatient clinic from January to July 2022. Change in seizure frequency and percentage of CLZ-associated side effects were determined as primary and secondary outcomes, respectively. Potential drug-drug interactions (Level C and above) were evaluated by using Lexicomp Drug Interaction Checker. RESULTS: The analysis included a total of 29 adult patients (15F, median age 29). The switching ratio was 10 mg CLB for every 1 mg CLZ (101). Seizure frequency was higher during the CLZ period compared to the CLB period (p < 0.05), but no status epilepticus cases were observed. All patients exhibited potential drug-drug interactions, leading to reduced CLZ levels in 12 cases. A total of 36 CLZ-associated side effects were identified, with fatigue (19.4 %), drowsiness (16.6 %), and somnolence (13.8 %) being the most prevalent. A positive and strong correlation was found between CLZ dose and the number of side effects (r 0.556; p 0.002). CONCLUSION: The abrupt switch from CLB to CLZ was observed to increase seizure frequency without leading to status epilepticus in PWE. CLZ-associated side effects were found to be tolerable despite the abrupt switch. Future studies may explore the effect of alternative switching ratios.