Zonisamide Side Effects

Brand Names: Zonegran

Please note - some side effects for Zonisamide may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA at http://www.fda.gov/medwatch/ or 1-800-FDA-1088 (1-800-332-1088).

Side Effects of Zonisamide - for the Consumer

Zonisamide

All medicines may cause side effects, but many people have no, or minor, side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome when using Zonisamide:

Abnormal skin sensations; diarrhea; dizziness; drowsiness; flu-like symptoms; headache; irritability; loss of appetite; nausea; stomach upset; tiredness; trouble sleeping.

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); bone pain; changes in the amount of urine produced; confusion; dark or bloody urine; decreased sweating; double vision or other vision problems; fainting; fast breathing; fast, slow, or irregular heartbeat; fever, chills, or sore throat; loss of coordination; memory problems; mental or mood changes (eg, agitation, depression); mouth sores; painful urination; persistent loss of appetite; red, swollen, blistered, or peeling skin; severe muscle pain or weakness; severe or persistent drowsiness; sluggishness; sudden stomach or back pain; suicidal thoughts or actions; swelling of the hands, ankles, or feet; tremor; trouble speaking or other speech problems; trouble thinking or concentrating; unusual bruising or bleeding; unusual eye movements; unusual or disturbing thoughts; unusual tiredness or weakness.

Zonisamide Side Effects - for the Professional

Zonisamide

The most commonly observed adverse events associated with the use of Zonisamide in controlled clinical trials that were not seen at an equivalent frequency among placebo-treated patients were somnolence, anorexia, dizziness, headache, nausea, and agitation/irritability.

In controlled clinical trials, 12% of patients receiving Zonisamide as adjunctive therapy discontinued due to an adverse event compared to 6% receiving placebo. Approximately 21% of the 1,336 patients with epilepsy who received Zonisamide in clinical studies discontinued treatment because of an adverse event. The adverse events most commonly associated with discontinuation were somnolence, fatigue and/or ataxia (6%), anorexia (3%), difficulty concentrating (2%), difficulty with memory, mental slowing, nausea/vomiting (2%), and weight loss (1%). Many of these adverse events were dose-related.

Adverse Event Incidence in Controlled Clinical Trials:

Table 3 lists treatment-emergent adverse events that occurred in at least 2% of patients treated with Zonisamide in controlled clinical trials that were numerically more common in the Zonisamide group. In these studies, either Zonisamide or placebo was added to the patient's current AED therapy. Adverse events were usually mild or moderate in intensity.

The prescriber should be aware that these figures, obtained when Zonisamide was added to concurrent AED therapy, cannot be used to predict the frequency of adverse events in the course of usual medical practice when patient characteristics and other factors may differ from those prevailing during clinical studies. Similarly, the cited frequencies cannot be directly compared with figures obtained from other clinical investigations involving different treatments, uses, or investigators. An inspection of these frequencies, however, does provide the prescriber with one basis by which to estimate the relative contribution of drug and non-drug factors to the adverse event incidences in the population studied.

Other Adverse Events Observed During Clinical Trials:

Zonisamide has been administered to 1,598 individuals during all clinical trials, only some of which were placebo-controlled. During these trials, all events were recorded by the investigators using their own terms. To provide a useful estimate of the proportion of individuals having adverse events, similar events have been grouped into a smaller number of standardized categories using a modified COSTART dictionary. The frequencies represent the proportion of the 1,598 individuals exposed to Zonisamide who experienced an event on at least one occasion. All events are included except those already listed in the previous table or discussed in WARNINGS or PRECAUTIONS, trivial events, those too general to be informative, and those not reasonably associated with Zonisamide.

Events are further classified within each category and listed in order of decreasing frequency as follows: frequent occurring in at least 1:100 patients; infrequent occurring in 1:100 to 1:1000 patients; rare occurring in fewer than 1:1000 patients.

Frequent: Accidental injury, asthenia. Infrequent: Chest pain, flank pain, malaise, allergic reaction, face edema, neck rigidity. Rare: Lupus erythematosus.

Infrequent: Palpitation, tachycardia, vascular insufficiency, hypotension, hypertension, thrombophlebitis, syncope, bradycardia. Rare: Atrial fibrillation, heart failure, pulmonary embolus, ventricular extrasystoles.

Frequent: Vomiting. Infrequent: Flatulence, gingivitis, gum hyperplasia, gastritis, gastroenteritis, stomatitis, cholelithiasis, glossitis, melena, rectal hemorrhage, ulcerative stomatitis, gastro-duodenal ulcer, dysphagia, gum hemorrhage. Rare: Cholangitis, hematemesis, cholecystitis, cholestatic jaundice, colitis, duodenitis, esophagitis, fecal incontinence, mouth ulceration.

 Infrequent: Leukopenia, anemia, immunodeficiency, lymphadenopathy. Rare: Thrombocytopenia, microcytic anemia, petechia.

Infrequent: Peripheral edema, weight gain, edema, thirst, dehydration. Rare: Hypoglycemia, hyponatremia, lactic dehydrogenase increased, SGOT increased, SGPT increased.

Infrequent: Leg cramps, myalgia, myasthenia, arthralgia, arthritis.

Frequent: Tremor, convulsion, abnormal gait, hyperesthesia, incoordination. Infrequent: Hypertonia, twitching, abnormal dreams, vertigo, libido decreased, neuropathy, hyperkinesia, movement disorder, dysarthria, cerebrovascular accident, hypotonia, peripheral neuritis, parathesia, reflexes increased. Rare: Circumoral paresthesia, dyskinesia, dystonia, encephalopathy, facial paralysis, hypokinesia, hyperesthesia, myoclonus, oculogyric crisis.

Infrequent: Euphoria.

 Frequent: Pharyngitis, cough increased. Infrequent: Dyspnea. Rare: Apnea, hemoptysis.

 Frequent: Pruritus. Infrequent: Maculopapular rash, acne, alopecia, dry skin, sweating, eczema, urticaria, hirsutism, pustular rash, vesiculobullous rash.

 Frequent: Ambylopia, tinnitus. Infrequent: Conjuctivitis, parosmia, deafness, visual field defect, glaucoma. Rare: Photophobia, iritis.

Infrequent: Urinary frequency, dysuria, urinary incontinence, hematuria, impotence, urinary retention, urinary urgency, amenorrhea, polyuria, nocturia. Rare: Albuminuria, enuresis, bladder pain, bladder calculus, gynecomastia, mastitis, menorrhagia.

Zonisamide Capsules

The most commonly observed adverse events associated with the use of Zonisamide in controlled clinical trials that were not seen at an equivalent frequency among placebo-treated patients were somnolence, anorexia, dizziness, headache, nausea, and agitation/irritability.

In controlled clinical trials, 12% of patients receiving Zonisamide as adjunctive therapy discontinued due to an adverse event compared to 6% receiving placebo. Approximately 21% of the 1,336 patients with epilepsy who received Zonisamide in clinical studies discontinued treatment because of an adverse event. The adverse events most commonly associated with discontinuation were somnolence, fatigue and/or ataxia (6%), anorexia (3%), difficulty concentrating (2%), difficulty with memory, mental slowing, nausea/vomiting (2%), and weight loss (1%). Many of these adverse events were dose-related.

Adverse Event Incidence in Controlled Clinical Trials

Table 3 lists treatment-emergent adverse events that occurred in at least 2% of patients treated with Zonisamide in controlled clinical trials that were numerically more common in the Zonisamide group. In these studies, either Zonisamide or placebo was added to the patient's current AED therapy. Adverse events were usually mild or moderate in intensity.

The prescriber should be aware that these figures, obtained when Zonisamide was added to concurrent AED therapy, cannot be used to predict the frequency of adverse events in the course of usual medical practice when patient characteristics and other factors may differ from those prevailing during clinical studies. Similarly, the cited frequencies cannot be directly compared with figures obtained from other clinical investigations involving different treatments, uses, or investigators. An inspection of these frequencies, however, does provide the prescriber with one basis by which to estimate the relative contribution of drug and nondrug factors to the adverse event incidences in the population studied.

Other Adverse Events Observed During Clinical Trials

Zonisamide has been administered to 1,598 individuals during all clinical trials, only some of which were placebo-controlled.

During these trials, all events were recorded by the investigators using their own terms. To provide a useful estimate of the proportion of individuals having adverse events, similar events have been grouped into a smaller number of standardized categories using a modified COSTART dictionary. The frequencies represent the proportion of the 1,598 individuals exposed to Zonisamide who experienced an event on at least one occasion. All events are included except those already listed in the previous table or discussed in WARNINGS or PRECAUTIONS, trivial events, those too general to be informative, and those not reasonably associated with Zonisamide.

Events are further classified within each category and listed in order of decreasing frequency as follows: frequent occurring in at least 1:100 patient; infrequent occurring in 1:100 to 1:1000 patients; rare occurring in fewer than 1:1000 patients.

Body as a Whole: Frequent: Accidental injury, asthenia. Infrequent: Chest pain, flank pain, malaise, allergic reaction, face edema, neck rigidity. Rare: Lupus erythematosus.

Cardiovascular: Infrequent: Palpitation, tachycardia, vascular insufficiency, hypotension, hypertension, thrombophlebitis, syncope, bradycardia. Rare: Atrial fibrillation, heart failure, pulmonary embolus, ventricular extrasystoles.

Digestive: Frequent: Vomiting. Infrequent: Flatulence, gingivitis, gum hyperplasia, gastritis, gastroenteritis, stomatitis, cholelithiasis, glossitis, melena, rectal hemorrhage, ulcerative stomatitis, gastro-duodenal ulcer, dysphagia, gum hemorrhage. Rare: Cholangitis, hematemesis, cholecystitis, cholestatic jaundice, colitis, duodenitis, esophagitis, fecal incontinence, mouth ulceration.

Hematologic and Lymphatic: Infrequent: Leukopenia, anemia, immunodeficiency, lymphadenopathy. Rare: Thrombocytopenia, microcytic anemia, petechia.

Metabolic and Nutritional: Infrequent: Peripheral edema, weight gain, edema, thirst, dehydration. Rare: Hypoglycemia, hyponatremia, lactic dehydrogenase increased, SGOT increased, SGPT increased.

Musculoskeletal: Infrequent: Leg cramps, myalgia, myasthenia, arthralgia, arthritis.

Nervous System: Frequent: Tremor, convulsion, abnormal gait, hyperesthesia, incoordination. Infrequent: Hypertonia, twitching, abnormal dreams, vertigo, libido decreased, neuropathy, hyperkinesia, movement disorder, dysarthria, cerebrovascular accident, hypotonia, peripheral neuritis, parathesia, reflexes increased. Rare: Circumoral paresthesia, dyskinesia, dystonia, encephalopathy, facial paralysis, hypokinesia, hyperesthesia, myoclonus, oculogyric crisis.

Behavioral Abnormalities – Non-Psychosis-Related: Infrequent: Euphoria.

Respiratory: Frequent: Pharyngitis, cough increased. Infrequent: Dyspnea. Rare: Apnea, hemoptysis.

Skin and Appendages: Frequent: Pruritus. Infrequent: Maculopapular rash, acne, alopecia, dry skin, sweating, eczema, urticaria, hirsutism, pustular rash, vesiculobullous rash.

Special Senses: Frequent: Amblyopia, tinnitus. Infrequent: Conjunctivitis, parosmia, deafness, visual field defect, glaucoma. Rare: Photophobia, iritis.

Urogenital: Infrequent: Urinary frequency, dysuria, urinary incontinence, hematuria, impotence, urinary retention, urinary urgency, amenorrhea, polyuria, nocturia. Rare: Albuminuria, enuresis, bladder pain, bladder calculus, gynecomastia, mastitis, menorrhagia.

Side Effects by Body System

General

General side effects have included somnolence (17%), headache (10%), fatigue (8%), tiredness (7%), abdominal pain (6%), and flu syndrome (4%).

Gastrointestinal

Gastrointestinal side effects have included anorexia (13%), nausea (9%), diarrhea (5%), dyspepsia (3%), constipation (2%), and dry mouth (2%).

Nervous system

Nervous system side effects have included dizziness (13%), ataxia (6%), nystagmus (4%), and paresthesia (4%). A case of restless legs syndrome has also been reported.

Other

Patients (especially pediatric patients) treated with zonisamide should be monitored closely for evidence of decreased sweating and increased body temperature, especially in warm or hot weather.

Reports have shown pediatric patients to be at an increased risk for zonisamide-associated oligohidrosis and hyperthermia.

Other side effects have included speech abnormalities (5%), difficulties in verbal expression (2%), taste perversion (2%), and visual hallucinations.

Psychiatric

Psychiatric side effects have included agitation/irritability (9%), confusion (6%), difficulty concentrating (6%), difficulty with memory (6%), depression (6%), insomnia (6%), mental slowing (4%), anxiety (3%), nervousness (2%), and schizophrenic/schizophreniform behavior (2%). A case of zonisamide-induced mania has also been reported.

Two cases of zonisamide induced behavior disorders have been reported in children with plasma levels within or below the therapeutic range. A case of zonisamide induced mania has been reported.

Ocular

Ocular side effects have included diplopia (6%).

Dermatologic

Dermatologic side effects have included rash (3%). A case of toxic epidermal necrolysis has also been reported.

Metabolic

Metabolic side effects have included weight loss (3%) and metabolic acidosis

Hematologic

Hematologic side effects have included ecchymosis (2%).

Respiratory

Respiratory side effects have included rhinitis (2%).

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