Zarontin Side Effects
Generic name: ethosuximide
Note: This document contains side effect information about ethosuximide. Some of the dosage forms listed on this page may not apply to the brand name Zarontin.
Some side effects of Zarontin may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.
For the Consumer
Applies to ethosuximide: oral capsule, oral syrup
Get emergency medical help if you have any of these signs of an allergic reaction while taking ethosuximide (the active ingredient contained in Zarontin) hives; difficult breathing; swelling of your face, lips, tongue, or throat.
Report any new or worsening symptoms to your doctor, such as: mood or behavior changes, anxiety, depression, panic attacks, trouble sleeping, or if you feel impulsive, irritable, agitated, hostile, aggressive, restless, hyperactive (mentally or physically), or have thoughts about suicide or hurting yourself.
Call your doctor at once if you have a serious side effect such as:
fever, chills, swollen glands, flu symptoms, sore throat, swollen glands, feeling very weak;
new or worsening cough with fever, trouble breathing;
easy bruising, unusual bleeding (nose, mouth, vagina, or rectum), purple or red pinpoint spots under your skin;
joint pain or swelling with mild fever, muscle aches;
chest pain, irregular heart rhythm, feeling short of breath;
patchy skin color, red spots, or a butterfly shaped skin rash over your cheeks and nose (worsens in sunlight);
skin rash, severe tingling, numbness, pain, muscle weakness;
upper stomach pain, loss of appetite, dark urine, jaundice (yellowing of the skin or eyes);
confusion, hallucinations, unusual thoughts or behavior, extreme fear;
swelling, rapid weight gain, urinating less than usual or not at all;
the first sign of any skin rash, no matter how mild;
severe skin reaction -- fever, sore throat, swelling in your face or tongue, burning in your eyes, skin pain, followed by a red or purple skin rash that spreads (especially in the face or upper body) and causes blistering and peeling; or
worsening of seizures.
Less serious side effects of ethosuximide may include:
upset stomach, mild nausea, stomach cramps, diarrhea, weight loss;
swelling in your tongue or gums;
headache, dizziness, drowsiness, feeling tired;
lack of balance or coordination; or
unusual vaginal bleeding.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects.
For Healthcare Professionals
Applies to ethosuximide: oral capsule, oral syrup
Gastrointestinal side effects have frequently included anorexia, vague gastric upset, nausea, vomiting, cramps, epigastric and abdominal pain, weight loss, and diarrhea. Gum hypertrophy and swelling of the tongue have also been reported.
Hematologic side effects have included leukopenia, agranulocytosis, pancytopenia (with or without bone marrow suppression), and eosinophilia.
Nervous system side effects have included drowsiness, headache, dizziness, euphoria, hiccups, irritability, hyperactivity, lethargy, fatigue, and ataxia.
The manufacturer reports psychiatric side effects associated with ethosuximide (the active ingredient contained in Zarontin) therapy may be more frequent in patients who have previously exhibited psychosocial abnormalities.
Psychiatric side effects have included sleep disturbances, night terrors, inability to concentrate, and aggressiveness. Paranoid psychosis, increased libido, and increased state of depression with overt suicidal intentions have been reported rarely.
Dermatologic side effects have included urticaria, Stevens-Johnson syndrome (SJS), systemic lupus erythematosus, pruritic erythematous rashes, and hirsutism. SJS symptoms usually manifest within 28 days, but may occur later and can be fatal.
Ocular side effects have included myopia.
Genitourinary side effects have included vaginal bleeding and microscopic hematuria.
Other side effects reported postmarketing have included Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS).
More Zarontin resources
- Zarontin Prescribing Information (FDA)
- Zarontin MedFacts Consumer Leaflet (Wolters Kluwer)
- Zarontin Concise Consumer Information (Cerner Multum)
- Zarontin Monograph (AHFS DI)
- Zarontin Advanced Consumer (Micromedex) - Includes Dosage Information
- Ethosuximide Professional Patient Advice (Wolters Kluwer)
- Ethosuximide Prescribing Information (FDA)
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