Zarontin Ethosuximide 250 mg/5mL Solution
🆔 Identity & classification
Where does this data come from?
🏷️ RxNorm drug class
This medicine belongs to the Anti-epileptic Agent class.
Where does this data come from?
🏭 Manufacturer & labeler
Where does this data come from?
🩺 Clinical
Ethosuximide is used to control absence seizures (petit mal) (a type of seizure in which there is a very short loss of awareness during which the person may stare straight ahead or blink his eyes and does not respond to others). Ethosuximide is in a class of medications called anticonvulsants. It works by reducing abnormal electrical activity in the brain.
Read the full MedlinePlus article ↗- An absence seizure is a brief episode — usually just a few seconds — where you or your child suddenly stares blankly and loses awareness, then snaps back as if nothing happened. Th...
- What exactly is an absence seizure, and will ethosuximide stop them?
- Ethosuximide comes as a capsule or a liquid solution, and you take it by mouth. Your doctor will start you on a lower dose and gradually increase it until your seizures are well co...
- How do I take it, and does it matter if I take it with food?
Patient education
Supplement & herbal interactions
Some supplements/herbs that may interact with Ethosuximide — tap one for details:
Ethosuximide may be associated with lower levels of 1 nutrient — worth a chat with your pharmacist, not a cause for alarm.
Where does this data come from?
Ask a licensed pharmacist directly — free, answered by our team.
💊 What it looks like
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🧪 Inactive Ingredients / Excipients
Inactive ingredients, also called excipients, are components of the drug product other than the active ingredient. They may include fillers, dyes, coatings, preservatives, flavors, or other formulation ingredients.
💡 Tap an ingredient (hover on desktop) to see what it is and why it’s used.
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UNII 2968PHW8QP
A weak organic acid derived from citrus fruits or made through fermentation. It works as a buffer to control pH, a preservative to extend shelf life, and a flavoring agent in medications.
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UNII WZB9127XOA
A synthetic red dye used to color medications and make them easier to identify. It serves as a colorant in tablets, capsules, and liquid formulations.
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UNII H77VEI93A8
A synthetic yellow dye used to color medications. It helps identify the drug and make it visually distinctive, with no effect on how the medicine works.
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UNII PDC6A3C0OX
Glycerin is a clear, thick liquid derived from plant oils or fats. It acts as a humectant to retain moisture, a sweetener, and a solvent in medications.
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UNII SB8ZUX40TY
Saccharin sodium is an artificial sweetener made from saccharin salt. It's added to medicines to improve taste, especially in liquid formulations for children or bitter drugs.
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UNII OJ245FE5EU
Sodium benzoate is a salt derived from benzoic acid, a preservative. It's added to medicines to prevent growth of bacteria, fungi, and other microorganisms that could spoil the product.
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UNII 1Q73Q2JULR
Sodium citrate is a salt derived from citric acid. It works as a buffer to maintain the medicine's pH level and may also help improve taste or act as a preservative in the formulation.
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UNII C151H8M554
A natural sugar derived from sugar cane or sugar beets. It's used as a sweetener, filler, and binder to improve taste, add bulk, and help hold tablet or capsule ingredients together.
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UNII 059QF0KO0R
Water is a liquid solvent that dissolves and mixes ingredients together in liquid medicines, syrups, and injections. It helps distribute the active drug evenly throughout the product.
9 inactive ingredients listed in the exact product block matched to this NDC.
Where does this data come from?
ingredient classCode="IACT" elements from the exact product block matched by this NDC. Label-section narrative from DailyMed / the openFDA label index is shown separately when available.Inactive ingredient FAQ
Are inactive ingredients the same for every manufacturer?
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💲 Pricing
A drug doesn't have one price. Each row is a different public payment system, and none is what you'd pay at the counter — that depends on your insurance. The ⓘ on each row explains what it measures.
| Price system | Per mL | Per package |
|---|---|---|
| Retail pharmacies payNADAC · weekly | Not in the retail survey — common for institutional, discontinued, or low-volume packs. | |
| Medicaid paysCMS SDUD · 12 mo | $0.2778 | $131.68 / 474 ml |
| Medicare drug plans payPart D · Q2 2026 | $0.3166 | $150.07 / 474 ml |
Where does this data come from?
🔁 Therapeutic equivalents
| Product | Labeler | Pack | NADAC/unit | TE | Status | Price vs. this |
|---|---|---|---|---|---|---|
| Ethosuximide 250 mg/5mL 59762-2350-06 | Mylan | 1 bottle | $0.081 | AA | FDA listed | — |
| Ethosuximide 250 mg/5mL 00121-0670-16 | PAI | 473 ml | $0.094 | AA | Availability likely | — |
| Zarontin 250 mg/5mLthis 00071-2418-19 | Parke-Davis | 1 bottle | — | AA | FDA listed | — |
| Ethosuximide 250 mg/5mL 62135-0064-47 | Chartwell | 473 ml | — | AA | FDA listed | — |
| Ethosuximide 250 mg/5mL 68999-0064-24 | Chartwell | 10 cups | — | AA | FDA listed | — |
Where does this data come from?
⏳ Availability & generic status
This product is an FDA-approved generic. Other versions of the same drug are listed under Therapeutic equivalents, least expensive first.
Where does this data come from?
🗺️ Medicaid utilization & spend
💊 Medicaid utilization by pack size
📊 Medicare Part D spend CMS · PART D · 2026 (Q1)
📦 Packaging — all sizes for this product
| Package NDC | Description | Marketing start | Status |
|---|---|---|---|
| 00071-2418-19 You're viewing this | 1 BOTTLE, PLASTIC in 1 CARTON (0071-2418-19) / 474 mL in 1 BOTTLE, PLASTIC | 2022-06-01 | Active |
| 00071-2418-35 | 1 BOTTLE, PLASTIC in 1 CARTON (0071-2418-35) / 474 mL in 1 BOTTLE, PLASTIC | 2020-03-10 | Active |
In Medicaid, this is the most-dispensed pack of this product — about 100% of fills over the last four reported quarters. See all packs ↓
Pack size FAQ
What quantity is in NDC 00071-2418-19?
What NDC number is used to bill for this package of Zarontin Ethosuximide 250 mg/5mL Solution?
🧭 About this NDC listing & data coverage
What data is (and isn’t) available for this NDC — tap to expand
| NDC identity (package / product / labeler codes) | ✓ Available |
| Labeler | ✓ Available |
| Product & package description | ✓ Available |
| Marketing category & status | ✓ Available |
| Active ingredient / dosage form / route | ✓ Available |
| FDA label (SPL via DailyMed) | ✓ Available |
| Package photos | ✓ Available |
| Inactive ingredients (structured) | ✓ Available |
| NADAC pharmacy acquisition price (CMS) | — Not published for this NDC CMS publishes NADAC only for NDCs reported in its retail-pharmacy survey. |
| Orange Book / therapeutic-equivalence data | ✓ Available |
| HCPCS J-code billing crosswalk | — Not published for this NDC Most self-administered / retail products have no J-code — that is normal. |
| Medicaid utilization (CMS SDUD) | ✓ Available |
Questions about this listing
Why is there no price listed?
Is the NDC printed on the package the same as the 11-digit billing NDC?
What do the three segments of this NDC mean?
Is this package still being marketed?
Does this product come in other package sizes?
Who lists this product with the FDA?
Do I need a prescription for this product?
Where does this data come from?
📄 Full prescribing information FDA SPL
🎯 Indications and Usage ▾
INDICATIONS AND USAGE Zarontin is indicated for the control of absence (petit mal) epilepsy.
⏱️ Dosage and Administration ▾
DOSAGE AND ADMINISTRATION Zarontin is administered by the oral route. The initial dose for patients 3 to 6 years of age is one teaspoonful (250 mg) per day; for patients 6 years of age and older, 2 teaspoonfuls (500 mg) per day. The dose thereafter must be individualized according to the patient's response.
Dosage should be increased by small increments. One useful method is to increase the daily dose by 250 mg every four to seven days until control is achieved with minimal side effects. Dosages exceeding 1.5 g daily, in divided doses, should be administered only under the strictest supervision of the physician.
The optimal dose for most pediatric patients is 20 mg/kg/day. This dose has given average plasma levels within the accepted therapeutic range of 40 to 100 mcg/mL. Subsequent dose schedules can be based on effectiveness and plasma level determinations.
Zarontin may be administered in combination with other anticonvulsants when other forms of epilepsy coexist with absence (petit mal). The optimal dose for most pediatric patients is 20 mg/kg/day.
⛔ Contraindications ▾
CONTRAINDICATIONS Ethosuximide should not be used in patients with a history of hypersensitivity to succinimides.
⚠️ Warnings ▾
WARNINGS 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 (e.g., sore throat, fever) develop, blood counts should be considered at that point. Drug-Induced Immune Thrombocytopenia: Drug-induced immune thrombocytopenia (DITP) has been reported with ethosuximide.
In the reported cases, the onset of symptoms occurred 1 to 3 weeks after initiation of ethosuximide; one patient had recurrence of symptoms within 1 day of a subsequent re-challenge with the drug. In those cases in which the platelet count was specified, the nadir was 2,000 and 3,000/mm 3 . When DITP is suspected, discontinue Zarontin, monitor serial platelet counts, and treat as appropriate.
If possible, assess the presence of drug-dependent antiplatelet antibodies. Avoid future use of Zarontin in patients with history of ethosuximide-induced DITP. 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. Suicidal Behavior and Ideation: Antiepileptic drugs (AEDs), including Zarontin, increase the risk of suicidal thoughts or behavior in patients taking these drugs for any indication.
Patients treated with any AED for any indication should be monitored for the emergence or worsening of depression, suicidal thoughts or behavior, and/or any unusual changes in mood or behavior. Pooled analyses of 199 placebo-controlled clinical trials (mono- and adjunctive therapy) of 11 different AEDs showed that patients randomized to one of the AEDs had approximately twice the risk (adjusted Relative Risk 1.8, 95% CI:1.2, 2.7) of suicidal thinking or behavior compared to patients randomized to placebo. In these trials, which had a median treatment duration of 12 weeks, the estimated incidence rate of suicidal behavior or ideation among 27,863 AED-treated patients was 0.43%, compared to 0.24% among 16,029 placebo-treated patients, representing an increase of approximately one case of suicidal thinking or behavior for every 530 patients treated.
There were four suicides in drug-treated patients in the trials and none in placebo-treated patients, but the number is too small to allow any conclusion about drug effect on suicide. The increased risk of suicidal thoughts or behavior with AEDs was observed as early as one week after starting drug treatment with AEDs and persisted for the duration of treatment assessed. Because most trials included in the analysis did not extend beyond 24 weeks, the risk of suicidal thoughts or behavior beyond 24 weeks could not be assessed.
The risk of suicidal thoughts or behavior was generally consistent among drugs in the data analyzed. The finding of increased risk with AEDs of varying mechanisms of action and across a range of indications suggests that the risk applies to all AEDs used for any indication. The risk did not vary substantially by age (5–100 years) in the clinical trials analyzed.
Table 1 shows absolute and relative risk by indication for all evaluated AEDs. Table 1 Risk by indication for antiepileptic drugs in the pooled analysis Indication Placebo Patients with Events Per 1000 Patients Drug Patients with Events Per 1000 Patients Relative Risk: Incidence of Events in Drug Patients/Incidence in Placebo Patients Risk Difference: Additional Drug Patients with Events Per 1000 Patients Epilepsy 1.0 3.4 3.5
2.4Psychiatric 5.7 8.5 1.5
2.9Other 1.0 1.8 1.9
0.9Total 2.4…
🤒 Adverse Reactions ▾
ADVERSE REACTIONS Body As A Whole: Allergic reaction, Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS). 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, eosinophilia, and thrombocytopenia (see WARNINGS ). 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. Integumentary System: Dermatologic manifestations which have occurred with the administration of ethosuximide have included urticaria, pruritic erythematous rashes, Stevens-Johnson syndrome, and hirsutism.
Special Senses: Myopia. Genitourinary System: Vaginal bleeding, microscopic hematuria.
🔄 Drug Interactions ▾
Drug Interactions: Since Zarontin (ethosuximide) may interact with concurrently administered antiepileptic drugs, periodic serum level determinations of these drugs may be necessary (e.g., ethosuximide may elevate phenytoin serum levels and valproic acid has been reported to both increase and decrease ethosuximide levels).
🤰 Pregnancy ▾
Pregnancy: To provide information regarding the effects of in utero exposure to Zarontin, physicians are advised to recommend that pregnant patients taking Zarontin enroll in the (NAAED) Pregnancy Registry. This can be done by calling the toll free number 1-888- 233-2334, and must be done by patients themselves. Information on the registry can also be found at the website: http://www.aedpregnancyregistry.org/. See WARNINGS .
🧒 Pediatric Use ▾
Pediatric Use: Safety and effectiveness in pediatric patients below the age of 3 years have not been established. (See DOSAGE AND ADMINISTRATION section.)
🆘 Overdosage ▾
OVERDOSAGE Acute overdoses may produce nausea, vomiting, and CNS depression including coma with respiratory depression. A relationship between ethosuximide toxicity and its plasma levels has not been established. The therapeutic range of serum levels is 40 mcg/mL to 100 mcg/mL, although levels as high as 150 mcg/mL have been reported without signs of toxicity.
Treatment: Treatment should include emesis (unless the patient is or could rapidly become obtunded, comatose, or convulsing) or gastric lavage, activated charcoal, cathartics, and general supportive measures. Hemodialysis may be useful to treat ethosuximide overdose. Forced diuresis and exchange transfusions are ineffective.
🧬 Clinical Pharmacology ▾
CLINICAL PHARMACOLOGY Ethosuximide suppresses the paroxysmal three cycle per second spike and wave activity associated with lapses of consciousness which is common in absence (petit mal) seizures. The frequency of epileptiform attacks is reduced, apparently by depression of the motor cortex and elevation of the threshold of the central nervous system to convulsive stimuli.
📦 How Supplied / Storage and Handling ▾
HOW SUPPLIED Zarontin is supplied as: NDC 0071-2418-19: 1 pint amber polyethylene terephthalate (PET) bottles (polyethylene cap liner). Each 5 mL of oral solution contains 250 mg ethosuximide in a raspberry flavored base. Store at 20°–25°C (68° – 77°F); [see USP Controlled Room Temperature] Preserve in tight containers. Protect from freezing and light.
📦 Storage and Handling ▾
Store at 20°–25°C (68° – 77°F); [see USP Controlled Room Temperature] Preserve in tight containers. Protect from freezing and light.
📋 Description ▾
DESCRIPTION Zarontin (ethosuximide) is an anticonvulsant succinimide, chemically designated as alpha-ethyl-alpha-methyl-succinimide, with the following structural formula: Each teaspoonful (5 mL), for oral administration, contains 250 mg ethosuximide, USP. Also contains citric acid, anhydrous, USP; FD&C red No. 40; FD&C yellow No.
6; flavor; glycerin, USP; purified water, USP; saccharin sodium, USP; sodium benzoate, NF; sodium citrate, USP; sucrose, NF. Chemical Structure
💬 Information for Patients ▾
Information for Patients: Inform patients of the availability of a Medication Guide, and instruct them to read the Medication Guide prior to taking Zarontin. Instruct patients to take Zarontin only as prescribed. Ethosuximide may impair the mental and/or physical abilities required for the performance of potentially hazardous tasks such as driving a motor vehicle or other such activity requiring alertness; therefore, the patient should be cautioned accordingly.
Patients taking ethosuximide should be advised of the importance of adhering strictly to the prescribed dosage regimen. Patients should be instructed to promptly contact their physician when they develop signs and/or symptoms suggesting an infection (e.g., sore throat, fever). Patients, their caregivers, and families should be counseled that AEDs, including Zarontin, may increase the risk of suicidal thoughts and behavior and should be advised of the need to be alert for the emergence or worsening of symptoms of depression, any unusual changes in mood or behavior, or the emergence of suicidal thoughts, behavior, or thoughts about self-harm.
Behaviors of concern should be reported immediately to healthcare providers. Prior to initiation of treatment with Zarontin, the patient should be instructed that a rash may herald a serious medical event and that the patient should report any such occurrence to a physician immediately. Patients should be encouraged to enroll in the North American Antiepileptic Drug (NAAED) Pregnancy Registry if they become pregnant.
This Registry is collecting information about the safety of antiepileptic drugs during pregnancy. To enroll, patients can call the toll free number 1-888-233-2334 (see PRECAUTIONS: Pregnancy section).
💬 Medication Guide ▾
MEDICATION GUIDE ZARONTIN, (Ză rŏn' tĭn) (ethosuximide) Capsules, Oral Solution Read this Medication Guide before you start taking ZARONTIN and each time you get a refill. There may be new information. This information does not take the place of talking to your healthcare provider about your medical condition or treatment.
If you have any questions about ZARONTIN, ask your healthcare provider or pharmacist. What is the most important information I should know about ZARONTIN? Do not stop taking ZARONTIN without first talking to your healthcare provider.
Stopping ZARONTIN suddenly can cause serious problems. ZARONTIN can cause serious side effects, including: 1. Rare but serious blood problems that may be life-threatening.
Call your healthcare provider right away if you have: • fever, swollen glands, or sore throat that come and go or do not go away • frequent infections or an infection that does not go away • easy bruising • red or purple spots on your body • bleeding gums or nose bleeds • severe fatigue or weakness 2. Drug reactions that may affect different parts of the body such as your liver, kidneys, heart , or blood cells. You may or may not have a rash with these types of reactions.
These reactions can be very serious and can cause death. Call your healthcare provider right away if you have any of these symptoms: • joint pain and swelling • muscle pain • fatigue, weakness • low-grade fever • pain in the chest that is worse with breathing • skin rash • swollen lymph glands • swelling of your face • yellowing of your skin or the white part of your eyes 3. Like other antiepileptic drugs, ZARONTIN may cause suicidal thoughts or actions in a very small number of people, about 1 in 500.
Call a healthcare provider right away if you have any of these symptoms, especially if they are new, worse, or worry you: • thoughts about suicide or dying • attempts to commit suicide • new or worse depression • new or worse anxiety • feeling agitated or restless • panic attacks • trouble sleeping (insomnia) • new or worse irritability • acting aggressive, being angry, or violent • acting on dangerous impulses • an extreme increase in activity and talking (mania) • other unusual changes in behavior or mood How can I watch for early symptoms of suicidal thoughts and actions? • Pay attention to any changes, especially sudden changes, in mood, behaviors, thoughts, or feelings. • Keep all follow-up visits with your healthcare provider as scheduled.
Call your healthcare provider between visits as needed, especially if you are worried about symptoms. Do not stop ZARONTIN without first talking to a healthcare provider. • Stopping ZARONTIN suddenly can cause serious problems. • Stopping a seizure medicine suddenly in a patient who has epilepsy can cause seizures that will not stop (status epilepticus). Suicidal thoughts or actions can be caused by things other than medicines.
If you have suicidal thoughts or actions, your healthcare provider may check for other causes. What is ZARONTIN? ZARONTIN is a prescription medicine used to treat absence (petit mal) seizures.
Who should not take ZARONTIN? Do not take ZARONTIN if you are allergic to succinimides (methsuximide or ethosuximide), or any of the ingredients in ZARONTIN. See the end of this Medication Guide for a complete list of ingredients in ZARONTIN.
What should I tell my healthcare provider before taking ZARONTIN? Before you take ZARONTIN, tell your healthcare provider if you: • have or had liver problems • have or have had depression, mood problems or suicidal thoughts or behavior • have any other medical conditions • are pregnant or plan to become pregnant. It is not known if ZARONTIN can harm your unborn baby.
Tell your healthcare provider right away if you become pregnant while taking ZARONTIN. You and your healthcare provider should decide if you should take ZARONTIN while you are pregnant. o If you become pregnant while taking ZARONTIN, talk to your healthcare provider about registering with…