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General Medication Fact Sheet for Zonisamide
| Field | Information |
|---|---|
| Generic Name | Zonisamide |
| Brand Name Versions | Zonegran |
| Boxed/Label Warning | May cause serious skin rashes, including Stevens-Johnson syndrome and toxic epidermal necrolysis. Discontinue immediately if signs of rash develop. |
| Purpose | Antiepileptic drug (AED) used to treat seizures and sometimes migraines. |
| Mechanism of Action | Blocks sodium and calcium channels, and enhances GABAergic neurotransmission in the brain. |
| Dosage Forms | Oral capsules |
| Available Strengths | 25 mg, 50 mg, 100 mg |
| Dosage Frequency | Typically once or twice daily, as directed by a healthcare provider. |
| Common Side Effects | Drowsiness, dizziness, ataxia, anorexia, headache, nausea. |
| Serious Side Effects | Serious skin rashes, metabolic acidosis, oligohidrosis (decreased sweating) and hyperthermia, suicidal thoughts/behavior, acute myopia and secondary angle closure glaucoma. |
| Drug Interactions | Other AEDs (e.g., phenytoin, carbamazepine), carbonic anhydrase inhibitors (e.g., acetazolamide), CNS depressants (e.g., alcohol, opioids). |
| Important Notes | Drink plenty of fluids to prevent kidney stones. Monitor for signs of depression or suicidal thoughts. Avoid activities requiring alertness until you know how zonisamide affects you. |
| Storage | Store at room temperature away from moisture and light. |
| Missed Dose | Take as soon as you remember; skip if it’s almost time for your next dose. Do not double the dose. |
| Alternatives | Lamotrigine, Levetiracetam, Topiramate, Valproic Acid. |
Zonisamide Alternatives
| Medication | Mechanism of Action | Notes |
|---|---|---|
| Lamotrigine (Lamictal) | Blocks voltage-sensitive sodium channels, stabilizes neuronal membranes. | Used for various seizure types and bipolar disorder. Requires slow titration to minimize risk of rash. |
| Levetiracetam (Keppra) | Binds to synaptic vesicle protein SV2A, modulating neurotransmitter release. | Broad-spectrum AED with relatively few drug interactions. |
| Topiramate (Topamax) | Blocks sodium channels, enhances GABA activity, antagonizes glutamate. | Also used for migraine prevention. May cause cognitive side effects. |
| Valproic Acid (Depakote) | Increases GABA levels in the brain. | Effective for a variety of seizure types, but has a higher risk of birth defects. |
Zonisamide Side Effects
| Common Side Effects | Serious Side Effects |
|---|---|
| Drowsiness | Serious skin rashes (Stevens-Johnson syndrome, toxic epidermal necrolysis) |
| Dizziness | Metabolic acidosis (kidney problems) |
| Ataxia (loss of coordination) | Oligohidrosis (decreased sweating) and hyperthermia (especially in children) |
| Anorexia (loss of appetite) | Suicidal thoughts/behavior |
| Headache | Acute myopia and secondary angle closure glaucoma |
| Nausea | Kidney Stones |
Zonisamide Dosage Guide
| Condition | Starting Dose | Maintenance Dose | Administration Notes |
|---|---|---|---|
| Partial Seizures (Adults) | 100 mg once daily | 200-400 mg daily (in one or two divided doses) | Titrate slowly to minimize side effects. |
| Partial Seizures (Children) | 1 mg/kg daily | 5-8 mg/kg daily (in one or two divided doses) | Do not exceed 400mg daily. Closely monitor for decreased sweating. |
