Adult: Initially, 50 mg daily in 2 divided doses, increase to 100 mg daily after 1 wk. Thereafter, may further increase dose at wkly intervals in increments of up to 100 mg. Usual maintenance dose: 300-500 mg daily, some patients may respond to lower doses. Child: > 6 yr Initially, 1 mg/kg once daily for 1 wk, may increase by increments of 1 mg/kg at wkly interval. Usual maintenance dose: 20-55 kg: 6-8 mg/kg once daily; >55 kg: 300-500 mg once daily, some may respond to lower dose.
Oral Monotherapy for partial seizures with or without secondary generalisation
Adult: In patients w/ newly diagnosed epilepsy: Initially, 100 mg once daily, increase to 200 mg once daily after 2 wk. May further increase by increments of 100 mg at intervals of at least 2 wk. Usual maintenance dose: 300 mg once daily, up to 500 mg daily.
GFR ≥50 mL/min: Slower dosage titration may be needed. GFR <50 mL/min: Not recommended.
Mild to moderate: Slower dosage titration may be needed. Severe: Not recommended.
May be taken with or without food.
History of hypersensitivity to sulfonamides.
Patient at risk of nephrolithiasis. Avoid abrupt withdrawal. Renal or hepatic impairment. Childn. Pregnancy and lactation.
Description: Zonisamide is a benzisoxazole derivative anticonvulsant containing sulfonamide. It may act on voltage sensitive Na and Ca channels, thereby affecting neuronal firing, hence reducing the spread of seizure discharges. It may modulate GABA-mediated neuronal inhibition. Pharmacokinetics: Absorption: Almost completely absorbed from GI tract. Bioavailability: Approx 100%. Time to peak plasma concentration: W/in 2-6 hr. Distribution: Widely distributed into body tissues. Crosses placenta and distributed into breast milk. Plasma protein binding: 40-50%; extensively bound to erythrocytes. Metabolism: Undergoes acetylation to N-acetylzonisamide and subsequent reduction mediated by CYP3A4 isoenzyme to 2-sulfamoylacetylphenol (SMAP). Excretion: Via urine (approx 15-30% as unchanged drug, 15% as N-acetylzonisamide, 50% as the glucuronide of SMAP). Plasma elimination half-life: Approx 63 hr.
Store between 15-30˚C. Protect from light and moisture.
N03AX15 - zonisamide ; Belongs to the class of other antiepileptics.
Anon. Zonisamide. Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 15/06/2016.Buckingham R (ed). Zonisamide. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 15/06/2016.Joint Formulary Committee. Zonisamide. British National Formulary [online]. London. BMJ Group and Pharmaceutical Press. https://www.medicinescomplete.com/. Accessed 15/06/2016.McEvoy GK, Snow EK, Miller J et al (eds). Zonisamide. AHFS Drug Information (AHFS DI) [online]. American Society of Health-System Pharmacists (ASHP). https://www.medicinescomplete.com. Accessed 15/06/2016.Zonisamide Capsule (Apotex Corp). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/. Accessed 15/06/2016.