Zonisamidum

Zonisamidum Uses, Dosage, Side Effects, Food Interaction and all others data.

The precise mechanism(s) by which zonisamide exerts its antiseizure effect is unknown. Zonisamidum demonstrated anticonvulsant activity in several experimental models. In animals, zonisamide was effective against tonic extension seizures induced by maximal electroshock but ineffective against clonic seizures induced by subcutaneous pentylenetetrazol. Zonisamidum raised the threshold for generalized seizures in the kindled rat model and reduced the duration of cortical focal seizures induced by electrical stimulation of the visual cortex in cats. Furthermore, zonisamide suppressed both interictal spikes and the secondarily generalized seizures produced by cortical application of tungstic acid gel in rats or by cortical freezing in cats. The relevance of these models to human epilepsy is unknown.Zonisamidum may produce these effects through action at sodium and calcium channels. In vitro pharmacological studies suggest that zonisamide blocks sodium channels and reduces voltagedependent, transient inward currents (T-type Ca2+ currents), consequently stabilizing neuronal membranes and suppressing neuronal hypersynchronization. In vitro binding studies have demonstrated that zonisamide binds to the GABA/benzodiazepine receptor ionophore complex in an allosteric fashion which does not produce changes in chloride flux. Other in vitro studies have demonstrated that zonisamide (10–30 μg/mL) suppresses synaptically-driven electrical activity without affecting postsynaptic GABA or glutamate responses (cultured mouse spinal cord neurons) or neuronal or glial uptake of [3H]-GABA (rat hippocampal slices). Thus, zonisamide does not appear to potentiate the synaptic activity of GABA. In vivo microdialysis studies demonstrated that zonisamide facilitates both dopaminergic and serotonergic neurotransmission.Zonisamidum is a carbonic anhydrase inhibitor. The contribution of this pharmacological action to the therapeutic effects of zonisamide is unknown. However, as a carbonic anhydrase inhibitor, zonisamide may cause metabolic acidosis

Zonisamidum is a sulfonamide and therefore unrelated to other seizure medications. The mechanism is not know but it may block sodium and calcium channels. Blocking of these channels may prevent neuronal hypersynchronization. Sonisamide has also been found to potentiate dopaminergic and serotonergic neurotransmission but does not appear to potentiate syanptic activity by GABA (gamma amino butyric acid).

Trade Name Zonisamidum
Availability Prescription only
Generic Zonisamide
Zonisamide Other Names Zonisamida, Zonisamide, Zonisamidum
Related Drugs diazepam, topiramate, levetiracetam, Keppra, Topamax, Valium
Type
Formula C8H8N2O3S
Weight Average: 212.226
Monoisotopic: 212.025562822
Protein binding

40% (at concentrations of 1.0-7.0 µg/mL)

Groups Approved, Investigational
Therapeutic Class Adjunct anti-epileptic drugs
Manufacturer
Available Country
Last Updated: September 19, 2023 at 7:00 am
Zonisamidum
Zonisamidum

Uses

Zonisamidum is used for adjunctive therapy in the treatment of partial seizures in adults with epilepsy.

Zonisamidum is also used to associated treatment for these conditions: Partial-Onset Seizures

How Zonisamidum works

Zonisamidum binds to sodium channels and voltage sensitive calcium channels, which suppresses neuronal depolarization and hypersynchronization. Zonisamidum also inhibits carbonic anhydrase to a weaker extent, but such an effect is not thought to contribute substantially to the drug's anticonvulsant activity.

Dosage

Zonisamidum dosage

Zonisamidumis 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. Zonisamidum should be administered once or twice daily, using 25 mg or 100 mg capsules. Zonisamidum is 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 Zonisamidum 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. Evidence from controlled trials suggests that Zonisamidum doses of 100-600 mg/day are effective, but there is no suggestion of increasing response above 400 mg/day. There is little experience with doses greater than 600 mg/day.

Side Effects

The most common adverse reactions with Zonisamidum (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 Zonisamidum 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 Zonisamidum in clinical studies discontinued treatment because of an adverse reaction. The most common adverse reactions leading to 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 reactions were doserelated

Toxicity

Symptoms of overdose include diminished breathing, loss of consciousness, low blood pressure, and slow heartbeat.

Precaution

Somnolence is commonly reported, especially at higher doses of Zonisamidum. Zonisamidum is metabolized by the liver and eliminated by the kidneys; caution should therefore be exercised when administering Zonisamidum to patients with hepatic and renal dysfunction

Food Interaction

  • Avoid alcohol. Ingesting alcohol may increase drowsiness and dizziness.
  • Take with or without food.

[Moderate] GENERALLY AVOID: Alcohol may potentiate some of the pharmacologic effects of CNS-active agents.

Use in combination may result in additive central nervous system depression and
MANAGEMENT: Patients receiving CNS-active agents should be warned of this interaction and advised to avoid or limit consumption of alcohol.

Ambulatory patients should be counseled to avoid hazardous activities requiring complete mental alertness and motor coordination until they know how these agents affect them, and to notify their physician if they experience excessive or prolonged CNS effects that interfere with their normal activities.

Volume of Distribution

  • 1.45 L/kg

Elimination Route

The absorption is rapid with a time to peak concentration of 2.8-3.9 hours. Food has not effect on bioavailability.

Half Life

63 hours

Clearance

  • 0.30 - 0.35 mL/min/kg [patients not receiving enzyme-inducing antiepilepsy drugs (AEDs)]
  • 0.35 - 0.5 mL/min/kg [Concomitant administration of phenytoin and carbamazepine]

Elimination Route

Zonisamidum is excreted primarily in urine as parent drug and as the glucuronide of a metabolite.

Pregnancy & Breastfeeding use

Zonisamidum may cause serious adverse fetal effects, based on clinical and nonclinical data. Zonisamidum was teratogenic in multiple animal species.Zonisamidum treatment causes metabolic acidosis in humans. The effect of zonisamide-induced metabolic acidosis has not been studied in pregnancy; however, metabolic acidosis in pregnancy (due to other causes) may be associated with decreased fetal growth, decreased fetal oxygenation, and fetal death, and may affect the fetus's ability to tolerate labor. Pregnant patients should be monitored for metabolic acidosis and treated as in the non-pregnant state. Newborns of mothers treated with zonisamide should be monitored for metabolic acidosis because of transfer of zonisamide to the fetus and possible occurrence of transient metabolic acidosis following birth. Transient metabolic acidosis has been reported in neonates born to mothers treated during pregnancy with a different carbonic anhydrase inhibitor.

Contraindication

Zonisamidum is contraindicated in patients who have demonstrated hypersensitivity to sulfonamides or zonisamide.

Special Warning

Patients With Renal Or Hepatic Disease: Because zonisamide is metabolized in the liver and excreted by the kidneys, patients with renal or hepatic disease should be treated with caution, and might require slower titration and more frequent monitoringPediatric Use: The safety and effectiveness of Zonisamidum in children under age 16 have not been established. Cases of oligohidrosis and hyperpyrexia have been reported. Zonisamidum commonly causes metabolic acidosis in pediatric patients. Chronic untreated metabolic acidosis in pediatric patients may cause nephrolithiasis and/or nephrocalcinosis, osteoporosis and/or osteomalacia (potentially resulting in rickets), and may reduce growth rates. A reduction in growth rate may eventually decrease the maximal height achieved. The effect of zonisamide on growth and bonerelated sequelae has not been systematically investigated.Geriatric Use: Single dose pharmacokinetic parameters are similar in elderly and young healthy volunteers. 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. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy.

Acute Overdose

Human Experience: Experience with Zonisamidum daily doses over 800 mg/day is limited. During Zonisamidum clinical development, three patients ingested unknown amounts of Zonisamidum 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 μg/mL measured 31 hours post-ingestion. Zonisamidum plasma levels fell with a half-life of 57 hours, and the patient became alert five days later.Management: No specific antidotes for Zonisamidum overdosage are available. Following a suspected recent overdose, emesis should be induced or gastriclavage performed with the usual precautions to protect the airway. General supportive care is indicated, including frequent monitoring of vital signs and close observation.Zonisamidum has a long half-life. Due to the low protein binding of zonisamide (40%), renal dialysis may be effective. The effectiveness of renal dialysis as a treatment of overdose has not been formally studied. A poison control center should be contacted for information on the management of Zonisamidum overdosage.

Innovators Monograph

You find simplified version here Zonisamidum

Zonisamidum contains Zonisamide see full prescribing information from innovator Zonisamidum Monograph, Zonisamidum MSDS, Zonisamidum FDA label

FAQ

What is the Zonisamidum used for?

Zonisamidum is used in combination with other medications to treat certain types of seizures.

What are side effects of Zonisamidum?

Zonisamidum may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

  • nausea,
  • vomiting,
  • weight loss,
  • changes in taste,
  • diarrhea,
  • constipation,
  • heartburn,
  • dry mouth,
  • headache,
  • dizziness,
  • confusion,
  • irritability,
  • difficulty falling asleep or staying asleep,
  • difficulty with memory,
  • pain, burning, numbness, or tingling in the hands or feet,
  • uncontrollable eye movements,
  • double vision,

Is Zonisamidum used for anxiety?

Zonisamidum may effectively augment response to anxiolytic medications in patients with treatment refractory anxiety.

Is Zonisamidum safe during pregnancy?

Zonisamidum may harm an unborn baby.Use effective birth control to prevent pregnancy, and tell your doctor if you become pregnant.

Is Zonisamidum safe during breastfeeding?

Zonisamidum is careful monitoring in exclusively breastfed infants.You should not breastfeed while using Zonisamidum.

Can I drink alcohol with Zonisamidum?

Alcohol can increase the nervous system side effects of Zonisamidum such as dizziness, drowsiness, and difficulty concentrating.You should avoid or limit the use of alcohol while being treated with Zonisamidum.

Can I take Zonisamidum for a long time?

Zonisamidum may cause metabolic acidosis .Metabolic acidosis that is left untreated for a long time may increase the risk that other medical problems, including kidney stones and bone problems that may lead to fractures, will develop.

Is Zonisamidum bad for liver?

Zonisamidum may cause serious allergic reactions called drug reaction with eosinophilia and systemic symptoms (DRESS) or multiorgan hypersensitivity, which may damage the liver, kidney, blood, heart, or muscles.

Is Zonisamidum a mood stabilizer?

Prevents seizures and stabilizes mood.Zonisamidum is used with other medicines to help control partial seizures.It can't be used by itself.

Can Zonisamidum be used to treat migraines?

Zonisamidum is effective and well tolerated for migraine prevention in patients refractory to topiramate. With the exception of the inhibition of T-type calcium channels by Zonisamidum, its mechanisms of action seem to be very similar to topiramate's.

Can Zonisamidum be abused?

The abuse and dependence potential of Zonisamidum has not been evaluated in human studies. In a series of animal studies,Zonisamidum did not demonstrate abuse liability and dependence potential.

When should I take Zonisamidum?

There is not a specific time of the day that you have to take Zonisamidum. However, it may be safer to take this medication in the evening time if you experience dizziness or sleepiness while on Zonisamidum.

How long does it take for Zonisamidum to work?

The Zonisamidum should begin working within 1-2 days.

What happens when I stop taking Zonisamidum?

Do not stop using Zonisamidum suddenly, even if you feel fine. Stopping suddenly may cause increased seizures.

Can Zonisamidum cause vision problems?

Taking Zonisamidum can cause permanent vision loss.

Will Zonisamidum make my weight gain?

No patients in the Zonisamidum group experienced significant weight gain.

Can Zonisamidum cause hyponatremia?

There were no cases of hyponatremia with Zonisamidum.

Can Zonisamidum be used alone?

Zonisamidum can be used alone or in combination with phenobarbital and/or potassium bromide.

Can I overdose on Zonisamidum?

Overdose symptoms may include slow heart rate, feeling light-headed, fainting, and slow or shallow breathing.

*** Taking medicines without doctor's advice can cause long-term problems.
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