Zarontin is approved for absence seizures. Ethosuximide is considered the first choice drug for treating absence seizures in part because it lacks the idiosyncratic hepatotoxicity of the alternative anti-absence drug, valproic acid.
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.
Before taking ethosuximide
Some medicines are not suitable for people with certain conditions, and sometimes a medicine may only be used if extra care is taken. For these reasons, before you (or your child if you are the carer) start taking ethosuximide it is important that your doctor knows:
- If you are pregnant, trying for a baby or breast-feeding.
- If you have any problems with the way your kidneys work, or with the way your liver works.
- If you have a rare inherited blood disorder called porphyria.
- If you are taking any other medicines. This includes any medicines you are taking which are available to buy without a prescription, such as herbal and complementary medicines.
- If you have ever had an allergic reaction to a medicine.
How to take ethosuximide
- Before you start the treatment, read the manufacturer's printed information leaflet from inside the pack. It will give you more information about ethosuximide and will provide you with a full list of the side-effects which you may experience from taking it.
- Take ethosuximide exactly as your doctor tells you to. Your dose will be printed on the label of the pack of medicine to remind you about what the doctor said. It is usual to start treatment on a low dose, and then for the dose to be increased gradually to a regular maintenance dose. It is usual to take two doses each day. Doses for children are tailored to their age and weight.
- Try to take your doses at the same times of day, each day. Having a routine will help you to remember to take your doses regularly. You can take ethosuximide either before or after meals. If you are taking capsules, swallow them with a drink of water.
- If you (or your child) have been given ethosuximide oral liquid medicine, remember to shake the bottle well before you measure out the dose. It is also a good idea to brush your (or your child's) teeth after each dose as the medicine contains sugar.
- If you forget to take a dose, take it as soon as you remember, unless it is nearly time for your next dose, in which case leave out the missed dose. Do not take two doses together to make up for a forgotten dose.
Getting the most from your treatment
- When you first start a new treatment for epilepsy there may be a change in the number or type of seizures you experience. Your doctor will advise you about this.
- Try to keep your regular appointments with your doctor. This is so your doctor can check on your progress.
- If you buy any medicines, check with a pharmacist that they are suitable for you to take.
- While you are being treated for epilepsy there is a small risk that you may develop mood changes, distressing thoughts and feelings about suicide. If this happens, you must tell your doctor about it straightaway.
- People with epilepsy must stop driving at first. Your doctor will advise you about when it may be possible for you to start driving again. This will usually be after a year free of seizures.
- Antiepileptic medicines can harm an unborn child. If you are a woman, make sure you have discussed with your doctor which types of contraception are suitable for you and your partner. If you want to have a family, discuss this with your doctor so that you can be given advice from a specialist before you become pregnant.
- You need to take ethosuximide regularly every day. Do not stop taking it unless your doctor tells you to stop. Stopping treatment suddenly can cause problems and your doctor will want you to reduce your dose gradually if this becomes necessary.
- If you drink alcohol, ask your doctor for advice. Your doctor may advise you not to drink alcohol while you are on this medicine.
Can ethosuximide cause problems?
Along with their useful effects, most medicines can cause unwanted side-effects although not everyone experiences them. The table below contains some of the most common ones associated with ethosuximide. You will find a full list in the manufacturer's information leaflet supplied with your medicine. The unwanted effects often improve as your body adjusts to the new medicine, but speak with your doctor or pharmacist if any of the following continue or become troublesome.
How to store ethosuximide
- Keep all medicines out of the reach and sight of children.
- Store in a cool, dry place, away from direct heat and light.
- 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 diarrhoea. 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.
- 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.
Zarontin 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.
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:
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
Systemic Lupus Erythematosus. Call your healthcare provider right away if you have any of these symptoms:
- joint pain and swelling
- muscle pain
- low-grade fever
- pain in the chest that is worse with breathing
- unexplained skin rash
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 should I avoid while taking Zarontin?
- Do not drink alcohol or take other medicines that make you sleepy or dizzy while taking Zarontin without first talking to your healthcare provider. Zarontin taken with alcohol or medicines that cause sleepiness or dizziness may make your sleepiness or dizziness worse.
- Do not drive, operate heavy machinery, or do other dangerous activities until you know how Zarontin affects you. Zarontin can slow your thinking and motor skills.