Zonisamide is used to treat certain types of seizures affecting individuals suffering from epilepsy.


What is Zonisamide?

Zonisamide is an anticonvulsant. Its exact mechanism of action has not yet been identified.


How should Zonisamide be taken?

Zonisamide is administered orally. It is typically taken in combination with other medications.


Side effects associated with Zonisamide

Zonisamide may be associated with severe skin reactions, decreased sweating (especially in children), heat stroke, metabolic acidosis and suicidal thoughts.


Among the other possible side effects of zonisamide include the following:


  • Diarrhea
  • Dizziness
  • Drowsiness
  • Headache
  • Loss of appetite
  • Nausea
  • Fatigue
  • Insomnia


It is important to contact a doctor immediately if you experience:


  • Rash
  • Urticaria
  • Difficulty breathing
  • Tightness in the chest
  • Swelling of the mouth, face, lips or tongue
  • Bone pain
  • Burning, numbness or tingling
  • Changes in urination frequency
  • Confusion
  • Loss of coordination
  • Decreased sweating
  • Vision problems
  • Memory problems
  • New seizures or worsening of pre-existing ones
  • Severe weakness or pain in the muscles
  • Severe or persistent drowsiness
  • Swelling of the hands, ankles or feet
  • Kidney stones
  • Tremors
  • Difficulty moving
  • Difficulty speaking
  • Difficulty focusing or concentrating  
  • Strange eye movements
  • Unusual thoughts and worries


Contraindications and warnings associated with the use of Zonisamide

Zonisamide is contraindicated in case of renal failure. The intake of the drug can impair the ability to drive or operate hazardous machinery. This side effect may be aggravated by alcohol and certain other medications.


Before starting treatment with zonisamide, it is important to tell your doctor if:

  • You have any allergies to the active substance, its excipients or to any other drugs (in particular aspirin), food or various substances (in particular dye tartrazine – CI 19140)
  • You are taking any other medications, herbal remedies or supplements. Mentioning in particular:  carbonic anhydrase inhibitors or anticholinergics
  • You are suffering (or have suffered) from status epilepticus, kidney or liver problems, breathing problems, metabolic acidosis, diarrhea, psychological or mood disorders
  • You are experiencing (or have experienced) suicidal thoughts
  • You are planning on undergoing surgery
  • You are following a ketogenic diet high in fat
  • You are pregnant or breast-feeding


During treatment, it is necessary to drink plenty of water. In addition, women of childbearing age must use effective birth control methods.


Treatment with zonisamide should never be stopped abruptly without a doctor’s consent. In turn, dangerous side effects may be triggered.


It is important to inform physicians, surgeons and dentists of any ongoing treatment with zonisamide.