Ethosuximide

Body As A Whole: Allergic reaction.

• Gastrointestinal System: Gastrointestinal symptoms occur frequently and include anorexia, vague gastric
  upset, nausea and vomiting, cramps, epigastric and abdominal pain, weight loss, and diarrhea. There have
  been reports of gum hypertrophy and swelling of the tongue.
• Hemopoietic System: Hemopoietic complications associated with the administration of ethosuximide have included leukopenia, agranulocytosis, pancytopenia, with or without bone marrow suppression, and
  eosinophilia.
• Nervous System: Neurologic and sensory reactions reported during therapy with ethosuximide have
  included drowsiness, headache, dizziness, euphoria, hiccups, irritability, hyperactivity, lethargy, fatigue,
  and ataxia. Psychiatric or psychological aberrations associated with ethosuximide administration have
  included disturbances of sleep, night terrors, inability to concentrate, and aggressiveness. These effects may be noted particularly in patients who have previously exhibited psychological abnormalities. There have been rare reports of paranoid psychosis, increased libido, and increased state of depression with overt suicidal intentions.

• Since Zarontin (ethosuximide) may interact with concurrently administered antiepileptic drugs, periodicserum level determinations of these drugs may be necessary (eg, ethosuximide may elevate phenytoin serum levels and valproic acid has been reported to both increase and decrease ethosuximide levels).

• Blood dyscrasias
  Blood dyscrasias, including some with fatal outcome, have been reported to be associated with the use of
  ethosuximide; therefore, periodic blood counts should be performed. Should signs and/or symptoms of
  infection (eg, sore throat, fever) develop, blood counts should be considered at that point.
• Effects on Liver and Kidneys
  Ethosuximide is capable of producing morphological and functional changes in the animal liver. In
  humans, abnormal liver and renal function studies have been reported. Ethosuximide should be
  administered with extreme caution to patients with known liver or renal disease. Periodic urinalysis and
  liver function studies are advised for all patients receiving the drug.
• Systemic Lupus Erythematosus
  Cases of systemic lupus erythematosus have been reported with the use of ethosuximide. The physician
  should be alert to this possibility.