Zonisamide monotherapy in newly diagnosed infantile spasms

Area of Science:

• Neurology
• Pediatric Neurology
• Clinical Pharmacology

Background:

• Infantile spasms (IS) is a severe epilepsy syndrome in infants.
• Early diagnosis and treatment are crucial for optimal neurodevelopmental outcomes.
• Current treatments have limitations, necessitating exploration of alternative therapies.

Purpose of the Study:

• To evaluate the short-term efficacy of zonisamide (ZNS) as monotherapy for newly diagnosed infantile spasms (IS).
• To assess the safety and tolerability of ZNS in this patient population.

Main Methods:

• An open, prospective trial involving 11 hospitals and 11 newly diagnosed IS patients.
• Zonisamide (3-10 mg/kg/day) was administered as a second-line treatment after high-dose vitamin B6 failure.
• Patients included 3 with cryptogenic IS and 8 with symptomatic IS.

Main Results:

• Four infants with symptomatic IS experienced cessation of spasms and disappearance of hypsarrhythmia.
• Spasm cessation occurred within 1-5 days at ZNS doses of 4-5 mg/kg/day, with plasma concentrations of 5.2-16.3 microg/ml.
• Two patients (50%) relapsed 4-6 weeks post-treatment; relapse correlated with persistent EEG abnormalities.
• No adverse reactions were reported during the study.

Conclusions:

• Zonisamide monotherapy demonstrates potential efficacy in the initial management of selected infantile spasm cases.
• EEG normalization appears to be a key predictor of sustained seizure freedom.
• Further research is warranted to optimize ZNS treatment protocols and predict long-term outcomes in IS.