Drug reference

Zonisamide

Antiepileptic · Epilepsy

AntiepilepticEpilepsy

CDSCO approvedSchedule H

EXCRETION

—

not curated

INTERACTIONS

12 major

SEVERE in our sources

PREGNANCY

Plasma-drug concentration monitoring during pregnancy is useful. Pregnant women with epilepsy should be encouraged to notify the UK Epilepsy and Pregnancy Register.

FDA category + note

Top interactionssee all 12 →

AcetazolamideSevereDatabaseDDInter
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AmitriptylineSevereDatabaseDDInter

Mechanism

Zonisamide is a sulfonamide derivative with multiple anticonvulsant mechanisms: it blocks both voltage-gated sodium channels and T-type calcium channels, weakly inhibits carbonic anhydrase (types II and III), and may enhance GABAergic inhibition and scavenge free radicals. This broad pharmacological profile provides efficacy against both focal and generalized seizure types. It has a long half-life (~63 hours) allowing once-daily dosing.

Indications

Treatment of epilepsyrefractory partial seizures (add-on drug)

Dosing

Adult: complex partial (CP) seizures in a dose of 60 mg discharge and ‘aura’ persist.. 1–3 times a day in adults; in children (3–5 mg/. GARDENAL 30, 60 mg tabs, 20 mg/5 ml syr; LUMINAL of voltage sensitive neuronal Na+ channel (Fig.. 30 mg tab, PHENOBARBITONE SODIUM 200 mg/ml inj.. Dose: 250–500 mg BD, children 10–20 mg/kg/day. not interfere with kindling. Its ability to selec-

Pharmacokinetics

Half-life

> 60 hours

Bioavailability

—

Protein binding

38–40%

Metabolism

small fraction is oxidized and conjugated with glucuronic acid

Excretion

29–48%

Contraindications

Previous hypersensitivity reaction to zonisamide
patients sensitive to sulfonamides

Side effects

Common

somnolencedizzinessheadacheirritabilityanorexia

Serious

Antiepileptic hypersensitivity syndrome (theoretical risk; symptoms may include fever, rash, lymphadenopathy, liver dysfunction, haematological, renal, pulmonary abnormalities, vasculitis, and multi-organ failure)
Increased risk of suicidal thoughts and behaviour
metabolic acidosis
renal stones

Pregnancy & lactation

Pregnancy

Plasma-drug concentration monitoring during pregnancy is useful. Pregnant women with epilepsy should be encouraged to notify the UK Epilepsy and Pregnancy Register.

Lactation

Readily transferred into breast-milk causing high infant serum-drug concentrations. Infants should be monitored for sedation, feeding difficulties, adequate weight gain, developmental milestones, and other adverse effects. Serum-drug concentration monitoring in breast-fed infants is advised if suspected adverse reactions develop; if toxicity occurs, formula feeds or weaning may be necessary.