Zonisamide

Zonisamide capsules are indicated as adjunctive therapy in the treatment of partial seizures in adults with epilepsy.

• Zonisamide capsules are recommended as adjunctive therapy
• For the treatment of partial seizures
• In adults
• Safety and efficacy
• In pediatric patients below the age of 16 have not been established
• Zonisamide capsules should be administered once or twice daily, using 25 mg, 50 mg or 100 mg capsules
• Zonisamide capsules are given orally and can be taken with or without food
• Capsules should be swallowed whole
• Adults over Age 16 The prescriber should be aware that, because of the long half-life of zonisamide, up to two weeks may be required to achieve steady state levels upon reaching a stable dose or following dosage adjustment
• Although the regimen described below is one that has been shown to be tolerated, the prescriber may wish to prolong the duration of treatment at the lower doses in order to fully assess the effects of zonisamide at steady state, noting that many of the side effects of zonisamide are more frequent at doses of 300 mg per day and above
• Although there is some evidence of greater response at doses above 100-200 mg/day, the increase appears small and formal dose-response studies have not been conducted
• The initial dose of zonisamide should be 100 mg daily
• After two weeks, the dose may be increased to 200 mg/day for at least two weeks
• It can be increased to 300 mg/day and 400 mg/day, with the dose stable for at least two weeks to achieve steady state at each level. …

• The safety and effectiveness of zonisamide in children under age 16 have not been established
• Acute myopia and secondary angle closure glaucoma have been reported
• In pediatric patients (see WARNINGS, Acute Myopia and Secondary Angle Closure Glaucoma subsection)
• Cases of oligohidrosis and hyperpyrexia have been reported (see WARNINGS, Oligohidrosis and Hyperthermia
• In Pediatric Patients subsection )
• Zonisamide commonly causes metabolic acidosis
• In pediatric patients (see WARNINGS, Metabolic Acidosis subsection). …

Single dose pharmacokinetic parameters are similar in elderly and young healthy volunteers (see CLINICAL PHARMACOLOGY, Specific Populations subsection ). Clinical studies of zonisamide did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. Other reported clinical experience has not identified differences in responses between the elderly and younger patients. …

• Inform patients of the availability of a Medication Guide, and instruct them to read the Medication Guide prior to taking zonisamide capsules
• Instruct patients to take zonisamide capsules only as prescribed
• Advise patients as follows: (See Medication Guide) 1
• Zonisamide may produce drowsiness, especially at higher doses
• Patients should be advised not to drive a car or operate other complex machinery until they have gained experience on zonisamide sufficient to determine whether it affects their performance. …

Zonisamide capsules are contraindicated in patients who have demonstrated hypersensitivity to sulfonamides or zonisamide.

Drug Interactions with CNS Depressants: Concomitant administration of zonisamide and alcohol or other CNS depressant drugs has not been evaluated in clinical studies. Because of the potential of zonisamide to cause CNS depression, as well as other cognitive and/or neuropsychiatric adverse events, zonisamide should be used with caution if used in combination with alcohol or other CNS depressants. …

Potentially Fatal Reactions to Sulfonamides: Fatalities have occurred, although rarely, as a result of severe reactions to sulfonamides (zonisamide is a sulfonamide) including Stevens-Johnson syndrome, toxic epidermal necrolysis, fulminant hepatic necrosis, agranulocytosis, aplastic anemia, and other blood dyscrasias. Such reactions may occur when a sulfonamide is readministered irrespective of the route of administration. If signs of hypersensitivity or other serious reactions occur, discontinue zonisamide immediately. Specific experience with sulfonamide-type adverse reaction to zonisamide is described below. …

The most common adverse reactions with zonisamide (an incidence at least 4% greater than placebo) in controlled clinical trials and shown in descending order of frequency were somnolence, anorexia, dizziness, ataxia, agitation/irritability, and difficulty with memory and/or concentration. In controlled clinical trials, 12% of patients receiving zonisamide as adjunctive therapy discontinued due to an adverse reaction 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 reaction. …

Pregnancy: (see WARNINGS, Teratogenicity subsection): Zonisamide may cause serious adverse fetal effects, based on clinical and nonclinical data. Zonisamide was teratogenic in multiple animal species. Zonisamide treatment causes metabolic acidosis in humans. …

Human Experience Experience with zonisamide daily doses over 800 mg/day is limited. During zonisamide clinical development, three patients ingested unknown amounts of zonisamide as suicide attempts, and all three were hospitalized with CNS symptoms. One patient became comatose and developed bradycardia, hypotension, and respiratory depression; the zonisamide plasma level was 100.1 mcg/mL measured 31 hours post-ingestion. Zonisamide plasma levels fell with a half-life of 57 hours, and the patient became alert five days later. …

The abuse and dependence potential of zonisamide has not been evaluated in human studies (see WARNINGS, Cognitive/Neuropsychiatric Adverse Events subsection ). In a series of animal studies, zonisamide did not demonstrate abuse liability and dependence potential. Monkeys did not self-administer zonisamide in a standard reinforcing paradigm. Rats exposed to zonisamide did not exhibit signs of physical dependence of the CNS-depressant type. …

تناولها عندما تتذكر، إلا إذا اقترب موعد الجرعة التالية. عندها تخطَّ الجرعة المنسية. لا تتناول جرعتين معًا أبدًا للتعويض. راجع النشرة، فبعض الأدوية مختلفة.