Consumer medicine information

Zarontin

Ethosuximide

BRAND INFORMATION

Brand name

Zarontin

Active ingredient

Ethosuximide

Schedule

S4

 

Consumer medicine information (CMI) leaflet

Please read this leaflet carefully before you start using Zarontin.

SUMMARY CMI

Zarontin

Consumer Medicine Information (CMI) summary

The full CMI on the next page has more details. If you are worried about using this medicine, speak to your doctor or pharmacist.

1. Why am I using Zarontin?

Zarontin contains the active ingredient ethosuximide. Zarontin is used to control epilepsy in children and children. Zarontin is used to control petit mal seizures. For more information, see Section 1. Why am I using Zarontin? in the full CMI.

2. What should I know before I use Zarontin?

Do not use if you have ever had an allergic reaction to Zarontin, succinimides or any of the ingredients listed at the end of the CMI. Talk to your doctor if you have any other allergies, medical conditions, take any other medicines, or are pregnant or plan to become pregnant or are breastfeeding. For more information, see Section 2. What should I know before I use Zarontin? in the full CMI.

3. What if I am taking other medicines?

Some medicines may interfere with Zarontin and affect how it works. A list of these medicines is in Section 3. What if I am taking other medicines? in the full CMI.

4. How do I use Zarontin?

  • Swallow Zarontin capsules while with a full glass of water.
  • For Zarontin syrup, shake the bottle well and accurately pour the dose with a medicine measure before taking it.

More instructions can be found in Section 4. How do I use Zarontin? in the full CMI.

5. What should I know while using Zarontin?

Things you should do
  • Remind any doctor, dentist or pharmacist you visit that you are using Zarontin.
  • Tell your doctor immediately if you are having thoughts about suicide or self-harm.
  • If you become pregnant while taking Zarontin, tell you doctor.
  • If you are breastfeeding, watch your baby carefully.
Things you should not do
  • Do not stop using this medicine unless your doctor tells you to.
  • Do not give Zarontin to anyone else, even if their symptoms seem similar to yours or they have the same condition as you.
Driving or using machines
  • Zarontin may cause dizziness, light-headedness, tiredness, drowsiness and affect alertness. Make sure you know how you react to Zarontin before you drive a car, operate machinery, or do anything else that could be dangerous if you are affected.
Drinking alcohol
  • Drinking alcohol when taking Zarontin can make you more sleepy, dizzy or lightheaded.
Looking after your medicine
  • Keep your capsules or syrup in a cool dry place where the temperature stays below 25°C.
  • Keep it where children cannot reach it.

For more information, see Section 5. What should I know while using Zarontin? in the full CMI.

6. Are there any side effects?

Speak to your doctor or pharmacist if you have any less serious side effects and they worry you. Tell your doctor as soon as possible if you: have thoughts of suicide or self-harm, notice unusual changes in mood or show signs of depression. Call your doctor straight away, or go straight to the Emergency Department at your nearest hospital if you notice any of these serious side effects: more frequent or severe seizures, severe depression, apparent intentions of suicide, aggressive behaviour, frequent infections, frequent nosebleeds, persistent nausea or vomiting, sudden signs of allergy, severe skin rash. For more information, including what to do if you have any side effects, see Section 6. Are there any side effects? in the full CMI.



FULL CMI

Zarontin

Active ingredient(s): ethosuximide


Consumer Medicine Information (CMI)

This leaflet provides important information about using Zarontin. You should also speak to your doctor or pharmacist if you would like further information or if you have any concerns or questions about using Zarontin.

Where to find information in this leaflet:

1. Why am I using Zarontin?
2. What should I know before I use Zarontin?
3. What if I am taking other medicines?
4. How do I use Zarontin?
5. What should I know while using Zarontin?
6. Are there any side effects?
7. Product details

1. Why am I using Zarontin?

Zarontin contains the active ingredient ethosuximide. Zarontin belongs to a group of medicines called anticonvulsants. These drugs are thought to work by controlling brain chemicals which send signals to nerves so that seizures (fits) do not happen.

Zarontin is used to control epilepsy in children and adults. Epilepsy is a condition where you have repeated seizures. There are many different types of seizures, ranging from mild to severe.

Zarontin is used to control petit mal seizures.

Zarontin may be used alone, or in combination with other medicines, to treat your condition.

Your doctor may have prescribed Zarontin for another reason. Ask your doctor if you have any questions about why Zarontin has been prescribed for you.

There is no evidence that Zarontin is addictive.

2. What should I know before I use Zarontin?

Warnings

Do not use Zarontin if:

  • you have an allergy to ethosuximide, other medicines which contain succinimides or any of the ingredients listed at the end of this leaflet.
  • Always check the ingredients to make sure you can use this medicine.

Symptoms of an allergic reaction to Zarontin may include (shortness of breath, wheezing or difficulty breathing, swelling of the face, lips, tongue or other parts of the body, rash, itching or hives on the skin.

Check with your doctor if you:

  • have allergies to:
    - any other medicines, especially barbiturates or any other anticonvulsant medicines
    - any other substances, such as foods, preservatives or dyes.
  • Have or have had any medical conditions, especially the following:
    - liver problems
    - kidney problems
    - systemic lupus erythematosus
    - frequent infections such as fever, chills, sore throat or mouth ulcers.

During treatment, you may be at risk of developing certain side effects. It is important you understand these risks and how to monitor for them. See additional information under Section 6. Are there any side effects?

Pregnancy and breastfeeding

Check with your doctor if you are pregnant or intend to become pregnant

If it is necessary for you to take Zarontin your doctor can help you decide whether or not to take it during pregnancy. Zarontin may affect your developing baby if you take it during pregnancy. However, it is very important to control your fits while you are pregnant.

Talk to your doctor if you are breastfeeding or intend to breastfeed

Your doctor will discuss the possible risks and benefits of taking Zarontin during breastfeeding.

If you do breastfeed, watch your baby carefully.

If your baby develops a skin rash becomes sleepy or has unusual symptoms, do not breastfeed again until you speak to your doctor.

If you have not told your doctor or pharmacist about any of the above, tell him or her before you start taking Zarontin.

3. What if I am taking other medicines?

Tell your doctor or pharmacist if you are taking any other medicines, including any medicines, vitamins or supplements that you buy without a prescription from your pharmacy, supermarket or health food shop.

Some medicines and Zarontin may interfere with each other. These include other medicines used to treat fits and convulsions, such as phenytoin and valproic acid.

These medicines may be affected by Zarontin, or may affect how well it works. You may need different amounts of your medicine, or you may need to take different medicines. Your doctor or pharmacist will advise you.

Check with your doctor or pharmacist if you are not sure about what medicines, vitamins or supplements you are taking and if these affect Zarontin.

4. How do I use Zarontin?

How much to take

  • Your doctor will tell you how much syrup or how many capsules you will need to take each day. This may depend on your age, the severity of your condition and whether or not you are taking any other medicines.
  • Your doctor may recommend that you start with a low dose of Zarontin and slowly increase the dose to the lowest amount needed to control your epilepsy/convulsions.
  • Follow all directions given to you by your doctor carefully. They may differ from the information contained in this leaflet.
  • Use Zarontin until your doctor tells you to stop.
  • If you do not understand the instructions on the bottle, ask your doctor or pharmacist for help.

When to take Zarontin

  • Take the daily dose of Zarontin in two divided doses.
  • Take Zarontin at about the same time each day.
  • Taking Zarontin at the same time each day will have the best effect. It will also help you remember when to take the capsules or syrup.
  • It does not matter if you take Zarontin before or after food.

How to take Zarontin

  • If you are taking Zarontin capsules: swallow Zarontin capsules whole with a full glass of water.
  • If you or your child are taking Zarontin syrup: Shake the bottle well and accurately pour the dose with a medicine measure before taking it.

Shaking the bottle and using a medicine measure will make sure that you get the correct dose. You can get a medicine measure from your pharmacist. Ask your pharmacist for ways to accurately measure the dose.

If you forget to use Zarontin

Zarontin should be used regularly at the same time each day. If you miss your dose at the usual time, take it as soon as you remember, and then go back to taking your medicine as you would normally.

If it is almost time for your next dose (within 4 hours), skip the dose you missed and take your next dose when you are meant to.

Do not take a double dose to make up for the dose you missed.

  • This may increase the chance of you getting an unwanted side effect.
  • If you are not sure what to do, ask your doctor or pharmacist.
  • If you have trouble remembering to take your medicine, ask your pharmacist for some hints.

How long to take Zarontin

  • Continue taking Zarontin for as long as your doctor tells you to.
  • Zarontin helps control your condition but does not cure it. Therefore, you must take your medicine every day, even if you feel well.
  • Do not stop taking Zarontin, or lower the dosage, without checking with your doctor. Do not let yourself run out of medicine over the weekend or on holidays.
  • Stopping Zarontin suddenly may cause unwanted effects or make your condition worse. Your doctor will slowly reduce your dose before you can stop taking it completely.

If you use too much Zarontin

If you think that you have used too much Zarontin, you may need urgent medical attention.

You should immediately:

  • phone the Poisons Information Centre
    (by calling 13 11 26 (Australia) or 0800 764 66 (New Zealand)), or
  • contact your doctor, or
  • go to the Emergency Department at your nearest hospital.

You should do this even if there are no signs of discomfort or poisoning.

5. What should I know while using Zarontin?

Things you should do

If you are about to be started on any new medicine, remind your doctor and pharmacist that you are taking Zarontin.

Tell any other doctors, dentists, and pharmacists who treat you that you are taking this medicine.

If you are going to have surgery, tell the surgeon or anaesthetist that you are taking this medicine. It may affect other medicines used.

If you become pregnant while taking Zarontin, tell your doctor.

Tell your doctor if you are breastfeeding or plan to breastfeed. If you do breastfeed, watch your baby carefully.

Tell your doctor if you feel Zarontin is not helping your condition. Your doctor may need to change your medicine.

Tell your doctor if, for any reason, you have not taken Zarontin exactly as prescribed. Otherwise, your doctor may change your treatment unnecessarily.

Be sure to keep all of your doctor's appointments so that your progress can be checked.

Your doctor will check your progress and may want to take some tests from time to time. This helps to prevent unwanted side effects.

Call your doctor straight away if you notice any of the following:

  • increase in seizures (fits)
  • itchy red skin rash or hives, fever, enlarged lymph glands

These symptoms may mean that you have a severe hypersensitivity reaction to this medicine. You may need urgent medical attention.

  • yellowing of the skin and/or eyes, swelling of the face, strong stomach pains, generally feeling unwell with tiredness, weakness and vomiting

These symptoms may mean that you have a serious condition affecting your liver. You may need urgent medical attention.

Suicide, mood and behaviour changes

Tell your doctor immediately if you have any thoughts about suicide or self-harm, any unusual changes in mood or behaviour, or you show signs of depression

Some people being treated with anti-epileptics such as Zarontin have thoughts of harming or killing themselves.

Patients and caregivers should be alert and monitor for these effects.

Signs and symptoms of suicide include:

  • thoughts or talk of death or suicide
  • thoughts or talk of self-harm or harm to others
  • any recent attempts of self-harm
  • increase in aggressive behaviour, irritability or agitation
  • feelings of depression.

Mention of suicide or violence must be taken seriously.

If you or someone you know is demonstrating these warning signs of suicide while taking Zarontin, contact your doctor or a mental health professional right away.

Things you should not do

  • Do not give Zarontin to anyone else, even if their symptoms seem similar to yours or they have the same condition as you.
  • Do not take Zarontin to treat any other complaints unless your doctor tells you to.
  • Do not stop taking it unless your doctor tells you to.

Driving or using machines

Be careful before you drive or use any machines or tools until you know how Zarontin affects you.

Zarontin may cause dizziness, light-headedness, tiredness, drowsiness and affect alertness. Make sure you know how you react to Zarontin before you drive a car, operate machinery, or do anything else that could be dangerous if you are affected.

Children

Children should not ride a bike, climb trees or do anything else that could be dangerous if they are feeling drowsy or sleepy.

Drinking alcohol

Tell your doctor if you drink alcohol.

Drinking alcohol when taking Zarontin can make you more sleepy, dizzy or lightheaded. Your doctor may advise you to avoid alcohol while you are being treated with Zarontin.

Looking after your medicine

Follow the instructions in the carton on how to take care of your medicine properly.

Keep your capsules in the pack until it is time to take them.

If you take the capsules out of the pack they will not keep well.

Keep your capsules or syrup in a cool dry place where the temperature stays below 25°C, away from moisture, heat or sunlight; for example, do not store it:

  • in the bathroom or near a sink, or
  • in the car or on window sills on hot days.

Heat and dampness can destroy some medicines.

Keep it where young children cannot reach it.

A locked cupboard at least one-and-a-half metres above the ground is a good place to store medicines.

Getting rid of any unwanted medicine

If you no longer need to use this medicine or it is out of date, take it to any pharmacy for safe disposal.

Do not use this medicine after the expiry date.

6. Are there any side effects?

Zarontin helps most people with epilepsy, but it may have unwanted side effects in a few people.

All medicines can have side effects. Sometimes they are serious, most of the time they are not. However, you may need medical treatment if you get some of the side effects.

If you are over 65 years of age you may have an increased chance of getting side effects.

See the information below and, if you need to, ask your doctor or pharmacist if you have any further questions about side effects.

Tell your doctor or pharmacist as soon as possible if you do not feel well while you are taking Zarontin.

If you get any side effects, do not stop taking Zarontin without first talking to your doctor or pharmacist.

Less serious side effects

Less serious side effectsWhat to do
  • dizziness or light-headedness
  • feeling tired or drowsy
  • headache
  • weakness, unsteadiness when walking
  • mood changes such as feelings of extreme happiness, irritability or excitement
  • hiccoughs
  • loss of concentration
  • disturbance of sleep
  • frightening dreams
  • abnormally suspicious thoughts
  • increased libido
  • indigestion, stomach pain or discomfort
  • nausea (feeling sick) or vomiting
  • cramps
  • loss of appetite
  • loss of weight
  • diarrhoea
  • swollen gums or tongue
  • itchy red skin rash or hives
  • excessive hairiness, especially in women
  • short sightedness
  • vaginal bleeding
  • allergic reaction
  • blood in the urine.
Speak to your doctor or pharmacist if you have any of these less serious side effects and they worry you.

Serious side effects

Serious side effectsWhat to do
  • have any thoughts of suicide or self-harm
  • notice any unusual changes in your mood or behaviour
  • show signs of depression.
Tell your doctor as soon as possible
  • more frequent or more severe seizures (fits)
  • severe depression, apparent intentions of suicide
  • aggressive behaviour
  • frequent infections with fever, chills, sore throat, swollen glands and mouth ulcers
  • frequent nosebleeds, unusual bleeding or bruising,
  • tiredness, headache, shortness of breath when exercising, dizziness or pale skin
  • persistent nausea or vomiting, loss of appetite, generally feeling unwell, fever, itching, yellowing of the skin and/or eyes, dark
  • coloured urine, light coloured bowel motions, pain in the abdomen. These may be signs of a liver problem.
  • sudden signs of allergy such as rash, itching or hives, swelling of the face, lips, wheezing or difficulty breathing
  • severe skin rash, itching, hives, blisters or peeling skin, which may be accompanied by fever, chills, headache, swollen glands, stomach pain or aching joints and muscles
  • severe whole body skin condition with severe blisters and bleeding in the lips, eyes, mouth, nose and genitals.
Call your doctor straight away or go straight to the Emergency Department at your nearest hospital if you notice any of these serious side effects.

Tell your doctor or pharmacist if you notice anything else that may be making you feel unwell.

Other side effects not listed here may occur in some people.

Reporting side effects

After you have received medical advice for any side effects you experience, you can report side effects to the Therapeutic Goods Administration online at www.tga.gov.au/reporting-problems. By reporting side effects, you can help provide more information on the safety of this medicine.

Always make sure you speak to your doctor or pharmacist before you decide to stop taking any of your medicines.

7. Product details

This medicine is only available with a doctor's prescription.

What Zarontin contains

Active ingredient
(main ingredient)

Capsules:

  • Ethosuzimide 250 mg

Syrup:

  • Ethosuzimide 250 mg/5 mL
Other ingredients
(inactive ingredients)

Capsules:

  • macrogol 400
  • gelatin
  • glycerol
  • sorbitol
  • vanillin
  • methyl hydroxybenzoate
  • propyl hydroxybenzoate
  • sunset yellow FCF.

Syrup:

  • sodium citrate
  • sodium benzoate
  • saccharin sodium
  • sucrose
  • glycerol
  • imitation raspberry flavour
  • purified water
  • citric acid monohydrate.
Potential allergens
  • benzoates
  • saccharin
  • sugars

Do not take this medicine if you are allergic to any of these ingredients.

What Zarontin looks like

Zarontin capsules 250 mg are clear orange soft gelatin capsules, available in bottles of 100 and 200 capsules (AUST R 94175)

Zarontin syrup is a clear yellow to pink solution, available in a 200 mL bottle (Aust R 79031).

Who distributes Zarontin

Zarontin is supplied by:

Clinect Pty Ltd
120-132 Atlantic Drive
Keysborough VIC 3173
Australia

Free Call Australia:
1800 899 005

Free Call New Zealand:
0800 138 803

This leaflet was prepared in November 2021.

Published by MIMS January 2022

BRAND INFORMATION

Brand name

Zarontin

Active ingredient

Ethosuximide

Schedule

S4

 

1 Name of Medicine

Ethosuximide.

2 Qualitative and Quantitative Composition

Zarontin contains the active component ethosuximide.
Each Zarontin capsule contains 250 mg ethosuximide. Zarontin syrup contains ethosuximide 250 mg/5 mL.

Excipients with known effect.

Zarontin syrup contains benzoates, saccharin and sugars.
For the full list of excipients, see Section 6.1 List of Excipients.

3 Pharmaceutical Form

Zarontin capsules.

Clear medium orange capsules printed P-D 237.

Zarontin syrup.

A clear slightly yellowish to slightly pinkish liquid.

4 Clinical Particulars

4.1 Therapeutic Indications

Zarontin is indicated for the control of petit mal epilepsy.

4.2 Dose and Method of Administration

Zarontin is administered orally.
Recommended initial daily dose for children and adults is approximately 20-30 mg/kg administered in two divided doses. This regimen will frequently achieve plasma levels in the therapeutic range of 40-100 mg/L (optimum 75 mg/L). As the dose serum level relationship may be curvilinear in individual patients 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. Plasma level monitoring is recommended. Zarontin may be administered in combination with other anticonvulsants when other forms of epilepsy coexist with petit mal.

4.3 Contraindications

Ethosuximide is contraindicated in patients with hypersensitivity to succinimides, ethosuximide or any component of this medication.

4.4 Special Warnings and Precautions for Use

General.

Ethosuximide, when used alone in mixed types of epilepsy, may increase the frequency of grand mal seizures in some patients. As with other anticonvulsants, it is important to proceed slowly when increasing or decreasing dosage, as well as when adding or eliminating other medication. Abrupt withdrawal of anticonvulsant medication may precipitate petit mal status.

Haematopoietic effect.

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 count determinations should be considered at that point.

Autoimmune disorders.

Cases of systemic lupus erythematosus have been reported with the use of ethosuximide. The physician should be alert to this possibility.

Serious dermatologic reaction.

Serious dermatologic reactions, including Stevens-Johnson syndrome (SJS), have been reported with ethosuximide treatment. SJS can be fatal. The onset of symptoms is usually within 28 days, but can occur later. Upon the appearance of a rash for which an alternative aetiology cannot be defined, ethosuximide should be discontinued.
Drug reaction with eosinophilia and systemic symptoms (DRESS) has been reported with ethosuximide exposure. DRESS consists of a combination of three or more of the following: cutaneous reaction (such as rash or exfoliative dermatitis), eosinophilia, fever, lymphadenopathy; and one or more systemic complications such as hepatitis, nephritis, pneumonitis, myocarditis, and pericarditis. DRESS is sometimes fatal. Discontinue ethosuximide if DRESS is suspected.

Suicidal behaviour and ideation.

Antiepileptic drugs (AEDs), including ethosuximide, increase the risk of suicidal thoughts or behaviour 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 behaviour, and/or any unusual changes in mood or behaviour (see Section 5.1 Pharmacodynamic Properties, Clinical trials).

Information for patients.

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 if they develop signs and/or symptoms (e.g. sore throat, fever) suggesting an infection.

Use in hepatic impairment.

Ethosuximide is capable of producing morphological and functional changes in the animal liver. In humans, abnormal liver function studies have been reported. Ethosuximide should be administered with extreme caution to patients with known liver disease. Periodic liver function studies are advised for all patients receiving the drug.

Use in renal impairment.

In humans, renal function studies have been reported. Ethosuximide should be administered with extreme caution to patients with known renal disease. Periodic urinalysis are advised for all patients receiving the drug.

Use in the elderly.

No data available.

Paediatric use.

See Section 4.2 Dose and Method of Administration.

Effects on laboratory tests.

No data available.

4.5 Interactions with Other Medicines and Other Forms of Interactions

Since 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).

4.6 Fertility, Pregnancy and Lactation

Effects on fertility.

No data available.
(Category D)
The risk of having an abnormal child as a result of antiepileptic medication is far outweighed by the dangers to the mother and fetus of uncontrolled epilepsy.
It is recommended that:
women on antiepileptic drugs (AEDs) receive prepregnancy counselling with regard to the risk of fetal abnormalities;
AEDs should be continued during pregnancy and monotherapy should be used if possible at the lowest effective dose as risk of abnormality is greater in women taking combined medication;
folic acid supplementation (5 mg) should be commenced four weeks prior to and continue for twelve weeks after conception;
specialist prenatal diagnosis including detailed midtrimester ultrasound should be offered.
Ethosuximide crosses the placenta. The risk of a mother with epilepsy giving birth to a baby with birth defects is about three times that of the general population. Cases of birth defects have been reported with ethosuximide.
Ethosuximide is excreted in human breast milk. Because the effects of ethosuximide on the nursing infant are unknown caution should be exercised when ethosuximide is administered to a nursing mother. Ethosuximide should be used in nursing mothers only if the benefits clearly outweigh the risks.

4.7 Effects on Ability to Drive and Use Machines

Ethosuximide may impair the mental and/or physical abilities required for the performance of potentially hazardous tasks, such as driving, using machinery or other such activity requiring alertness.

4.8 Adverse Effects (Undesirable Effects)

Blood and lymphatic system disorders.

Agranulocytosis, aplastic anaemia, eosinophilia, leucopoenia, pancytopenia, bone marrow failure, thrombocytopenia.

Immune system disorders.

Hypersensitivity.

Metabolism and nutrition disorders.

Decreased appetite.

Psychiatric disorders.

Aggression, euphoric mood, sleep terror, libido increased, increased state of depression, overt suicidal ideation, psychotic disorder, paranoid psychosis, disturbances of sleep, night terrors, inability to concentrate and sleep disorder.
Psychiatric or psychological aberrations associated with ethosuximide administration may be noted particularly in patients who have previously exhibited psychological abnormalities.

Nervous system disorders.

Drowsiness, dizziness, headache, ataxia, somnolence, psychomotor hyperactivity, hyperactivity, lethargy, disturbances in attention.

Eye disorders.

Myopia.

Respiratory, thoracic and mediastinal disorders.

Hiccups.

Gastrointestinal disorders.

Epigastric and abdominal pain, abdominal pain upper, anorexia, gastrointestinal disorder, diarrhoea, nausea, abdominal discomfort, vomiting, gingival hypertrophy, swollen tongue, vague gastric upset, cramps.

Skin and subcutaneous tissue disorders.

Drug reaction with eosinophilia and systemic symptoms, rash erythematous, Stevens-Johnson syndrome, urticaria, hirsutism.

Musculoskeletal and connective tissue disorders.

Systemic lupus erythematosus.

Renal and urinary disorders.

Haematuria.

Reproductive system and breast disorders.

Vaginal haemorrhage.

General disorders and administration site conditions.

Fatigue, irritability.

Investigations.

Weight decreased.

Reporting suspected adverse effects.

Reporting suspected adverse reactions after registration of the medicinal product is important. It allows continued monitoring of the benefit-risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions at www.tga.gov.au/reporting-problems.

4.9 Overdose

Symptoms.

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 is 40 microgram/mL to 100 microgram/mL, although levels as high as 150 microgram/mL have been reported without signs of toxicity.

Treatment.

Treatment is symptomatic and supportive of respiratory and cardiovascular functions. There is no specific antidote available. Activated charcoal may be used to reduce drug absorption and is most effective when administered within 1 hour of ingestion. In patients who are not fully conscious or have impaired gag reflex, consideration should be given to administering activated charcoal via nasogastric tube once the airway is protected.
Haemodialysis may be useful, but forced diuresis and exchange transfusions are ineffective.
Ipecac induced emesis is not recommended because of the potential for CNS depression.
For information on the management of overdose, contact the Poisons Information Centre on 13 11 26 (Australia).

5 Pharmacological Properties

5.1 Pharmacodynamic Properties

Mechanism of action.

Ethosuximide suppresses the paroxysmal spike and wave pattern which is common in 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.

Clinical trials.

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 behaviour compared to patients randomized to placebo. In these trials, which had a median treatment duration of 12 weeks, the estimated incidence rate of suicidal behaviour 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 behaviour 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 behaviour 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 behaviour beyond 24 weeks could not be assessed.
The risk of suicidal thoughts or behaviour was generally consistent among drugs in the data analysed. 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 analysed. Table 1 shows absolute and relative risk by indication for all evaluated AEDs.
The relative risk for suicidal thoughts or behaviour was higher in clinical trials for epilepsy than in clinical trials for psychiatric or other conditions, but the absolute risk differences were similar for the epilepsy and psychiatric indications.
Anyone considering prescribing ethosuximide or any other AED must balance this risk with the risk of untreated illness. Epilepsy and many other illnesses for which AEDs are prescribed are themselves associated with morbidity and mortality and an increased risk of suicidal thoughts and behaviour. Should suicidal thoughts and behaviour emerge during treatment, the prescriber needs to consider whether the emergence of these symptoms in any given patient may be related to the illness being treated.
Patients, their caregivers, and families should be informed that AEDs increase the risk of suicidal thoughts and behaviour and should be advised of the need to be alert for the emergence or worsening of the signs and symptoms of depression, any unusual changes in mood or behaviour, or the emergence of suicidal thoughts, behaviour, or thoughts about self harm. Behaviours of concern should be reported immediately to the treating doctor.

5.2 Pharmacokinetic Properties

No data available.

5.3 Preclinical Safety Data

Genotoxicity.

No data available.

Carcinogenicity.

No data available.

6 Pharmaceutical Particulars

6.1 List of Excipients

Capsule.

It also contains gelatin, glycerol, macrogol 400, Sorbitol Special Polyol (ARTG PI No: 3876), erythrosine, quinoline yellow and Opacode WB water based Monogramming Ink NSP-78-18022 White (ARTG PI No: 3883).

Syrup.

It also contains sodium benzoate (2.38 mg/mL as a preservative), sucrose (60 mg/mL), glycerol (12.5 mg/mL), saccharin sodium, sodium citrate dihydrate, citric acid monohydrate, Raspberry Flavour 23 P 082 (ARTG PI No: 4501) and purified water.

6.2 Incompatibilities

Incompatibilities were either not assessed or not identified as part of the registration of this medicine.

6.3 Shelf Life

In Australia, information on the shelf life can be found on the public summary of the Australian Register of Therapeutic Goods (ARTG). The expiry date can be found on the packaging.

6.4 Special Precautions for Storage

Capsule.

Store below 30°C.

Syrup.

Store below 25°C.

6.5 Nature and Contents of Container

Capsule.

HDPE bottles of 100 capsules or 200 capsules with PP child resistant closure.

Syrup.

Glass bottles of 200 mL with PP child resistant closure.

6.6 Special Precautions for Disposal

In Australia, any unused medicine or waste material should be disposed of by taking it to your local pharmacy.

6.7 Physicochemical Properties

Chemical structure.


Ethosuximide is chemically described as α-ethyl-α-methylsuccinimide with an empirical formula of C7H11NO2 and a molecular weight of 141.17. The molecular structure of ethosuximide is shown above.
Ethosuximide is a white or almost white powder or waxy solid, freely soluble in water, very soluble in alcohol, in ether and in methylene chloride.

CAS number.

77-67-8.

7 Medicine Schedule (Poisons Standard)

Schedule 4 - Prescription only Medicine.

Summary Table of Changes