II. Indications
- Adjunctive management of Partial Seizures
- Add to primary antiepileptic regimens
- Other potential uses currently being researched
- Myoclonic Seizures
- Infantile Spasm
- Atypical Absence Seizure
- Generalized Tonic Clonic Seizures
III. Contraindications
- Sulfonamide Allergy
- Pregnancy (Teratogenic in animals)
IV. Mechanism
- Anticonvulsant
- Sulfonamide derivative
- Blocks CNS Sodium and Calcium channels and stabilizes Neuron membranes, preventing hypersynchronization
- Also binds GABA Receptor ionophore complex, but does not appear to potentiate GABA activity at Synapse
- Facilitates the Neurotransmitters Dopamine and Serotonin
V. Dosing: Adults (and age >16 years)
- Initial: 100 mg orally daily for at least 2 weeks
- Increase: 100 mg every two weeks as needed
- Target: 400 mg/day divided once to twice daily
- Maximum: 600 mg/day (but doses above 400 mg/day do not appear to offer benefit)
- Caution: Increase more slowly in Renal Insufficiency and hepatic dysfunction
VI. Pharmacokinetics
- Weak carbonic anhydrase inhibitor
-
Sulfonamide that blocks Sodium and Calcium channels
- Increases Dopaminergic transmission
- Increases serotonergic transmission
- Metabolized by CYP3A4
- Drug levels affected by Phenytoin, Carbamazepine, Phenobarbital, Valproic Acid
- Half-Life: 60 hours
VII. Drug Interactions
- Increased Zonisamide clearance with CYP3A4 inducers
- Concurrent carbonic anhydrase inhibitor (Topamax)
- Increased Nephrolithiasis risk
VIII. Adverse effects
- Common
- Dizziness
- Ataxia
- Somnolence
- Nausea
- Anorexia
- Abdominal Pain
- Insomnia
- Impaired cognition
- Confusion
- Decreased concentration
- Speech problems
- Serious
- Psychosis
- Stevens Johnson Syndrome
- Toxic Epidermal Necrolysis
- Fulminant hepatic necrosis
- Narrow Angle Glaucoma (IOP may increase during first month of use)
- Childhood Adverse Effects
- Oligohydrosis
- Hyperthermia (and Heat Stroke)
- Other
- Nephrolithiasis (associated with Metabolic Acidosis)
X. Resources
Images: Related links to external sites (from Bing)
Related Studies
| zonisamide (on 12/21/2022 at Medicaid.Gov Survey of pharmacy drug pricing) | ||
| ZONISAMIDE 100 MG CAPSULE | Generic | $0.12 each |
| ZONISAMIDE 25 MG CAPSULE | Generic | $0.08 each |
| ZONISAMIDE 50 MG CAPSULE | Generic | $0.09 each |
Ontology: zonisamide (C0078844)
| Definition (NCI) | A sulfonamide derivative with an anticonvulsant property. The exact mechanism of action remains to be elucidated. Zonisamide appears to block sodium and calcium channels, thereby stabilizing neuronal membranes and suppressing neuronal hyper-synchronization. Although zonisamide shows affinity for the gamma-aminobutyric acid (GABA)/benzodiazepine receptor ionophore complex, it does not potentiate the synaptic activity of GABA. In addition, this agent also facilitates both dopaminergic and serotonergic neurotransmission. |
| Concepts | Pharmacologic Substance (T121) , Organic Chemical (T109) |
| MSH | C022189 |
| SnomedCT | 398762003, 125693002 |
| LNC | LP28438-7, MTHU013979 |
| English | 1,2-benzisoxazole-3-methanesulfonamide, 3-sulfamoylmethyl-1,2-benzisoxazole, 1,2-Benzisoxazole-3-methanesulfonamide, zonisamide (medication), ZONISAMIDE, zonisamide [Chemical/Ingredient], zonisamide, Zonisamide (product), Zonisamide (substance), Zonisamide |
| Spanish | zonisamida (producto), zonisamida (sustancia), zonisamida |
Ontology: Zonegran (C0876224)
| Concepts | Pharmacologic Substance (T121) , Organic Chemical (T109) |
| MSH | C022189 |
| English | Zonegran, zonegran, Elan brand of zonisamide |
