zonisamide (Rx)

Brand and Other Names:Zonegran
  • Print

Dosing & Uses

AdultPediatricGeriatric

Dosage Forms & Strengths

capsule

  • 25mg
  • 50mg
  • 100mg
more...

Partial Seizures

Initial: 100 mg PO qDay

Titrate up by 100 mg increments q2Week to no more than 600 mg PO qDay (may divide q12hr after 1st week)

Weight Loss (Off-label)

100 mg increments q2Week to no more than 600 mg PO qDay (may divide q12hr after first week); use 600 mg/day in patients who have not lost at least 5% of their initial body weight

Dosing Modifications

Renal impairment: Slower titration and more frequent monitoring advised; not recommended if patient's glomerular filtration rate is less than 50 mL/min

Hepatic impairment: Slower titration and more frequent monitoring advised

Dosage Forms & Strengths

capsule

  • 25mg
  • 50mg
  • 100mg
more...

<16 years

Not recommended

>16 years

Partial seizures

  • Same as in adults

Administer as in adults; initiate dosing at the lower end of the dosing range

Next:

Interactions

Interaction Checker

and zonisamide

No Results

     activity indicator 
    No Interactions Found
    Interactions Found

    Contraindicated

      Serious - Use Alternative

        Significant - Monitor Closely

          Minor

            All Interactions Sort By:
             activity indicator 
            Previous
            Next:

            Adverse Effects

            >10%

            Somnolence (17%)

            Anorexia (13%)

            Dizziness (13%)

            1-10%

            Headache (10%)

            Nausea (9%)

            Agitation (9%)

            Abdominal pain (6%)

            Ataxia (6%)

            Confusion (6%)

            Depression (6%)

            Diplopia (6%)

            Insomnia (6%)

            Diarrhea (5%)

            Speech disorder (5%)

            Flu-like symptoms (4%)

            Kidney stones (4%)

            Nystagmus (4%)

            Paresthesia (4%)

            Dysgeusia (3%)

            Weight loss (3%)

            Anxiety (3%)

            Rash (3%)

            Constipation (2%)

            Rhinitis (2%)

            Xerostomia (2%)

            Postmarketing Reports

            Acute pancreatitis

            Rhabdomyolysis

            Creatine phosphokinase increased

            Previous
            Next:

            Warnings

            Contraindications

            Hypersensitivity to zonisamide or sulfonamides

            Cautions

            Maintain fluid intake due to risk of kidney stone formation

            Discontinue treatment if significant sustained increase in creatinine occurs

            Anticonvulsants should not be discontinued abruptly as it may increase seizure frequency; withdraw therapy gradually unless safety concerns require a more rapid withdrawal

            Risk of serious skin reactions; consider discontinuation in patients who develop unexplained rash

            Significant CNS effects include psychiatric symptoms, including depression or psychosis, psychomotor slowing, including difficulty with concentration, speech or language problems, and fatigue or somnolence; may cause sedation, which may impair physical or mental abilities; patients must be about performing tasks, which require mental alertness

            Slowing and fatigue may occur within first month of treatment

            Creatinine and BUN elevations reported; monitor renal function and discontinue therapy if acute renal failure or significant sustained increase in creatinine/BUN concentration occurs; kidney stones also reported

            Risk of rare, but potentially fatal, anaphylactic reactions (including blood dyscrasias and skin reactions)

            Risk of metabolic acidosis; predisposing conditions include severe respiratory disease, renal disease, status epilepticus, ketogenic diet and other medications; serum bicarbonate should be monitored prior to initiation and during therapy; if metabolic acidosis occurs, consider decreasing the dose to tapering the dose to discontinue; consider alkali treatment if use continued despite acidosis; untreated metabolic acidosis may increase risk of developing nephrolithiasis, osteomalacia, nephrocalcinosis, or osteoporosis

            Use appropriate precautions for handling and disposal

            Increased risk of suicidal thoughts/behavior; risk observed as early as 1 week after initiating therapy; monitor all patients for notable changes that may indicate suicidal thoughts or depression

            Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS), also known as multi-organ hypersensitivity reported; early manifestations of hypersensitivity (e.g., fever, lymphadenopathy) may be present even though rash not evident; if such signs or symptoms present, evaluate immediately; discontinue therapy if an alternative etiology for signs or symptoms cannot be established

            Decreased sweating and hyperthermia, requiring hospitalization, reported in children; use with caution when used in combination with other drugs that may predispose patients to heat-related disorders

            Previous
            Next:

            Pregnancy & Lactation

            Pregnancy category: C

            Lactation: Unknown; avoid during breastfeeding

            Pregnancy Categories

            A:Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

            B:May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

            C:Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

            D:Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

            X:Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

            NA:Information not available.

            more...
            Previous
            Next:

            Pharmacology

            Mechanism of Action

            Unknown; benzisoxazole compound; more active against tonic phase than it is against clonic phase; may stabilize neuronal membranes by acting at sodium and calcium channels; does not affect GABA activity

            It has some weak carbonic anhydrase inhibitor activity

            Absorption

            Peak plasma time: 2-6 hr (concentration: 2-5 mcg/mL)

            Distribution

            Protein bound: 40%

            Vd: 1.45 L/kg

            Metabolism

            Hepatic; through CYP3A4

            Elimination

            Half-life: 63 hr

            Renal clearance: 3.5 mL/min

            Total body clearance: 0.30-0.35 mL/min/kg

            Excretion: Urine (62%); feces (3%)

            Previous
            Next:

            Images

            Previous
            Next:

            Formulary

            FormularyPatient Discounts

            Adding plans allows you to compare formulary status to other drugs in the same class.

            To view formulary information first create a list of plans. Your list will be saved and can be edited at any time.

            Adding plans allows you to:

            • View the formulary and any restrictions for each plan.
            • Manage and view all your plans together – even plans in different states.
            • Compare formulary status to other drugs in the same class.
            • Access your plan list on any device – mobile or desktop.

            The above information is provided for general informational and educational purposes only. Individual plans may vary and formulary information changes. Contact the applicable plan provider for the most current information.

            Tier Description
            1 This drug is available at the lowest co-pay. Most commonly, these are generic drugs.
            2 This drug is available at a middle level co-pay. Most commonly, these are "preferred" (on formulary) brand drugs.
            3 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs.
            4 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            5 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            6 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            NC NOT COVERED – Drugs that are not covered by the plan.
            Code Definition
            PA Prior Authorization
            Drugs that require prior authorization. This restriction requires that specific clinical criteria be met prior to the approval of the prescription.
            QL Quantity Limits
            Drugs that have quantity limits associated with each prescription. This restriction typically limits the quantity of the drug that will be covered.
            ST Step Therapy
            Drugs that have step therapy associated with each prescription. This restriction typically requires that certain criteria be met prior to approval for the prescription.
            OR Other Restrictions
            Drugs that have restrictions other than prior authorization, quantity limits, and step therapy associated with each prescription.
            Additional Offers
            Email to Patient

            From:

            To:

            The recipient will receive more details and instructions to access this offer.

            By clicking send, you acknowledge that you have permission to email the recipient with this information.

            Email Forms to Patient

            From:

            To:

            The recipient will receive more details and instructions to access this offer.

            By clicking send, you acknowledge that you have permission to email the recipient with this information.

            Previous
            Medscape prescription drug monographs are based on FDA-approved labeling information, unless otherwise noted, combined with additional data derived from primary medical literature.