Ethosuximide Generic

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*Based on the difference between the U&C price submitted and the price the patient paid, as of April 2023.

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  1. Medication
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  2. Ethosuximide
    Generic for Zarontin
    30 capsules $12 USD
    Save $77.40
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Do you need a prescription for ethosuximide?

Yes, ethosuximide is only available with a valid physician Rx.

How much is ethosuximide without Insurance in the US?

Our website gives two competitive savings options to US customers who wish to purchase ethosuximide, as either a brand or generic, if available. The first is access to medications through our mail-order online pharmacy. The second is by using the Now Patient Rx Advantage Card, which can be used in over 65,000 pharmacies nationwide, across America. If you are insured, then in most cases, the cash price will be significantly cheaper than the copay.

What will my out-of-pocket cost be for ethosuximide in the US?

There are no out-of-pocket (OOP) costs because we are currently only offering a cash-based option to purchase medications.

Is Now Patient a ethosuximide savings card?

Yes. Save up to 90% on your ethosuximide with the FREE Now Patient Rx Advantage card*.
*Based on the difference between the U&C submitted by the pharmacy and the price the patients pay.

Can you handle Rx transfers for home delivery in the US?

Yes. If you use the mail-order online pharmacy option, then we can handle requests by you to have your prescription transferred to our pharmacy for home delivery. We can even help you manage your refills by giving you timely reminders, so you do not run out of your medication.

Is Now Patient a ethosuximide coupon provider in the US?

No. Now Patient does not provide ethosuximide coupons or FREE ethosuximide samples.

Do you accept commercial, Medicare or Medicaid coverage for ethosuximide in the US?

No. Currently, we only offer cash-based options for purchase, therefore we do not require your insurance benefit details. In the future, our plan is to be able to handle commercial insurance, Medicare and Medicaid including cases where you have multiple health plans that provide benefit coverage (e.g. Medicaid and Commercial). We also anticipate being able to handle more complex scenarios such as using primary insurance combined with a manufacturer copay assistance program.

Does Now Patient work with Medicare?

Our cash-based prices for medications are typically cheaper than Medicare copays. We do not bill Medicare Part D (standalone drug coverage) or Medicare Advantage (combined health and drug coverage). When you purchase your medication from Now Patient, you will be doing so out of your pocket. The spend will not count towards your plan deductibles or gaps.

Does Now Patient work with Commercial Insurance?

Our cash-based prices for medications are typically cheaper than commercial plan copays. We do not bill your commercial plan. When you purchase your medication from Now Patient, you will be doing so out of your pocket. The spend will not count towards your plan deductibles or gaps.

What should you do if you use too much ethosuximide?


Call your doctor right away or seek immediate medical attention if your symptoms do not improve or they become worse after using ethosuximide. You can also call 800-222-1222 to reach the American Association of Poison Control Centers or use its online resource if you think you’ve used too much ethosuximide. But if you have severe symptoms, call 911 (or your local emergency number) immediately or go to the nearest emergency room.


If you think it is an emergency, call 999 or find your nearest A&E
If you need help now, but it’s not an emergency go to 111.nhs.uk or call 111. Alternatively you can speak to one of our pharmacists or use the Now Patient app to make an appointment with your GP.

What should I do if I miss my dose?

There are occasions when people forget to take their medication at correct prescribed times. This may not only have an effect on potentially making the medication less effective but it may also inadvertently lead to taking doses too close together, thereby increasing the risks of side effects.

Click here to find out what to do if you forgot to take your medication

What is generic ethosuximide?

Generic ethosuximide refers to the non-brand-name version of the medication. It contains the same active ingredient as the brand-name drug but is typically less expensive.

FDA approval of ethosuximide

Ethosuximide is approved by the U.S. Food and Drug Administration (FDA) for the treatment of absence seizures (petit mal seizures) associated with epilepsy.

Active ingredient of ethosuximide

The active ingredient of ethosuximide is ethosuximide.

US brand name of ethosuximide and manufacturer

Ethosuximide is available in the US under the brand name Zarontin. It is marketed by Parke-Davis (a division of Pfizer).

UK brand name of ethosuximide and manufacturer

In the UK, ethosuximide is available under the brand name Emeside. The manufacturer may vary depending on the brand name.

Prescription requirement for ethosuximide

A prescription (Rx) is required for ethosuximide in both the US and the UK.

Availability of ethosuximide in the UK with NHS prescription

Ethosuximide is available in the UK with an NHS prescription.

Conditions treated by ethosuximide

Ethosuximide is an anticonvulsant succinimide primarily used for the treatment of absence seizures/absence epilepsy (petit mal seizures) associated with epilepsy. It works by reducing abnormal electrical activity in the brain.

How does ethosuximide work?

The exact mechanism of action of ethosuximide in treating absence seizures is not fully understood. However, it is believed to work by reducing the activity of certain types of calcium channels in the brain. This helps stabilize the electrical activity in the brain and prevent the occurrence of absence seizures.

Forms of ethosuximide available

Ethosuximide is available in the form of oral capsules and oral solution.

Dosage of ethosuximide

The dosage of ethosuximide may vary depending on the individual’s age, weight, and specific seizure type. It is important to follow the medication guide provided by the healthcare provider.

Directions for ethosuximide use

Ethosuximide should be taken exactly as directed by the healthcare provider. The medication is usually taken two to three times a day with or without food. It is important to take ethosuximide regularly to maintain seizure control.

Warnings and precautions for ethosuximide

  • Ethosuximide should be used with caution in individuals with certain medical conditions, such as liver disease or kidney disease
  • It may interact with certain medications, including other antiepileptic drugs (AEDs). Inform the healthcare provider about all medications being taken
  • Ethosuximide may cause systemic lupus erythematosus (SLE). Symptoms include chest pain, fever, hair loss, muscle or joint pain, sore throat, skin rash, or trouble breathing
  • Stevens-Johnson syndrome, a serious skin reaction can occur with this medicine
  • Ethosuximide may cause suicidal thoughts and increased depression

Use of ethosuximide during pregnancy

Ethosuximide may cause birth defects. Talk to your caregiver if you’re pregnant or are planning to become pregnant.

Use of ethosuximide while breastfeeding

Ethosuximide may pass into breast milk, but its effects on the nursing infant are not well understood. It is recommended to consult a healthcare professional before using ethosuximide while breastfeeding.

Possible side effects of ethosuximide

Common side effects of ethosuximide may include dizziness, drowsiness, gastrointestinal disturbances, hiccups, loss of appetite, and weight loss. Serious side effects are rare but can occur. Promptly report any concerning symptoms to a healthcare provider. Get medical help right away if you have an allergic reaction. Symptoms include hives, trouble breathing, swelling of your face, tongue or throat, skin rash, and blistering or peeling of the skin. Promptly report any adverse effects to a healthcare provider.

Interactions with other drugs

Ethosuximide may interact with certain medications including other medications for seizures such as phenytoin, phenobarbital and valproic acid, sedatives or tranquilizers.  It is important to inform your healthcare provider about all the medications you are taking, including prescription drugs, over-the-counter (OTC) drugs, dietary supplements, multivitamins, and herbal products, to avoid any adverse effects and potential drug interactions.

Similar drugs to ethosuximide

Other antiepileptic drugs used for the treatment of absence seizures include methsuximide, valproic acid and lamotrigine.


  • FDA Prescribing Information for Ethosuximide
  • MHRA product information for Ethosuximide
  • WebMD – Ethosuximide
  • Drugs.com – Ethosuximide
  • NHS UK


Now Patient has taken all reasonable steps to ensure that all material is factually accurate, complete, and current. However, the knowledge and experience of a qualified healthcare professional should always be sought after instead of using the information in this page. Before taking any drug, you should always speak to your doctor or another qualified healthcare provider.

The information provided here about medications is subject to change and is not meant to include all uses, precautions, warnings, directions, drug interactions, allergic reactions, or negative effects. The absence of warnings or other information for a particular medication does not imply that the medication or medication combination is appropriate for all patients or for all possible purposes.

Stefano Mirabello Medical Reviewer
Pharmacist / B.Pharm
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