Classifications: anticonvulsant; sulfonamide; Therapeutic: anticonvulsant; sulfonamide
Pregnancy Category: C
25 mg, 50 mg, 100 mg capsules
A broad-spectrum anticonvulsant that facilitates dopaminergic and serotonergic neurotransmission but does not potentiate
the activity of gamma-aminobutyric acid (GABA) in the synapses of the neurons.
Suppresses focal spike discharges and electroshock seizures. Effective against a variety of seizure types.
Adjunctive therapy for partial seizures in adults.
Hypersensitivity to sulfonamides or zonisamide; pregnancy (category C), lactation; children <16 y.
Renal or hepatic insufficiency, dehydration, hypovolemia; renal impairment; concomitant administration of drugs that induce
or inhibit CYP3A4; older adults.
Route & Dosage
Adult: PO Start at 100 mg q.d., may increase after 2 wk to 200 mg/d, may then increase q2wk, if necessary (max: 400 mg/d in 12
- Do not crush or break capsules; ensure capsules are swallowed whole with adequate fluid.
- Withdraw drug gradually when discontinued to minimize seizure potential.
- Store at 25° C (77° F); room temperature permitted. Protect from light and moisture.
Adverse Effects (≥1%) Body as a Whole:
Flu-like syndrome, weight loss. CNS:
Agitation, irritability, anxiety, ataxia, confusion, depression
, difficulty concentrating, difficulty with memory, dizziness, fatigue
, headache, insomnia
, mental slowing, nervousness, nystagmus, paresthesia, schizophrenic behavior, somnolence,
tiredness, tremor, convulsion, abnormal gait, hyperesthesia, incoordination. GI:
Abdominal pain, anorexia, constipation
, diarrhea, dyspepsia, nausea, dry mouth, flatulence, gingivitis, gum hyperplasia, gastritis
, stomatitis, cholelithiasis,
glossitis, melena, rectal hemorrhage, ulcerative stomatitis, ulcer, dysphagia. Metabolic:
Oligohidrosis, sometimes resulting in heat stroke and hyperthermia in children. Respiratory:
Rhinitis, pharyngitis, cough. Skin:
Ecchymosis, rash, pruritus. Special Senses:
Difficulties in verbal expression, diplopia, speech abnormalities, taste perversion, amblyopia, tinnitus. Urogenital:
InteractionsDrug: Phenytoin, carbamazepine, phenobarbital, valproic acid
may decrease half-life of zonisamide.
26 h. Distribution:
40% protein bound, extensively binds to erythrocytes. Metabolism:
Acetylated in liver by CYP3A4. Elimination:
Primarily in urine. Half-Life:
Assessment & Drug Effects
- Withhold drug and notify physician if an unexplained rash or S&S of hypersensitivity appear (see Appendix F).
- Monitor for and report S&S of CNS impairment (somnolence, excessive fatigue, cognitive deficits, speech or language problems,
incoordination, gait disturbances); oligohidrosis (lack of sweating) and hyperthermia in pediatric patients.
- Lab tests: Periodic BUN and serum creatinine, and CBC with differential.
Patient & Family Education
- Do not abruptly stop taking this medication.
- Increase daily fluid intake to minimize risk of renal stones. Notify physician immediately of S&S of renal stones: sudden
back or abdominal pain, and blood in urine.
- Report any of the following: dizziness, excess drowsiness, frequent headaches, malaise, double vision, lack of coordination,
persistent nausea, sore throat, fever, mouth ulcers, or easy bruising.
- Exercise special caution with concurrent use of alcohol or CNS depressants.
- Do not drive or engage in other potentially hazardous activities until response to drug is known.