Introduction:
Modern evolution and technologies have helped discover various diseases and drugs. These drugs are found to be beneficial if administered in the recommended dosage. However, overdosing on drugs can lead to toxicity which can be fatal.
Ethosuximide is a drug used to treat seizures (abnormal brain activity) if taken in optimal doses. Hence, it is essential to know the indications, contraindications, therapeutic doses, and toxicity to understand the drug better.
What Is Ethosuximide?
Ethosuximide is an anticonvulsive and is classified under succinimide drugs used to treat absence seizures. Seizures or convulsions are the abnormal and uncontrolled electrical activity of the brain cells that may disrupt normal function. Most anticonvulsants help to calm or inhibit the hyperactivity of the brain. Ethosuximide is an FDA (Food and Drug Administration) approved drug and is available as a capsule and syrup that can be consumed orally.
The mechanism of action of the drug Ethosuximide is blocking the calcium channels and inhibiting the voltage-dependent calcium conductance of neurons. Neurons are the basic working unit of the nervous system and are information messengers that carry information via electrical impulses and chemical signals to different areas of the brain.
When Is Ethosuximide Indicated?
Ethosuximide has been indicated in the adjunctive treatment of seizures and convulsions, especially in the absence of seizures. An absence seizure is also known as petit mal seizure, in which the individual may stare blankly for a lapse in attention that lasts 10 to 20 seconds. It usually occurs in children and is characterized by movements like lip smacking and eye blinking.
When Is Ethosuximide Contraindicated?
Ethosuximide is contraindicated in patients with a known history of allergic reactions to the drug. In addition, the drug is contraindicated in medical conditions like kidney and liver disorders, myasthenia gravis (muscle disorder), systemic lupus erythematosus (autoimmune disease), depression, mood swings, and suicidal thoughts. It is also contraindicated in pregnant women as it has the potential to cause congenital disabilities in children.
What Is the Normal Dosage of Ethosuximide?
The administration of Ethosuximide in children below three years of age has yet to be clearly known. In children from three to six years of age, a daily dose of 250 mg and above six years of age, a daily dose of 500 grams, may be prescribed by the physician depending on the weight of the child and the severity of the condition. The therapeutic dose of Ethosuximide is 40 to 100 mg/L. Every oral capsule of Ethosuximide usually contains 250 mg of suspended particles, and every bottle of syrup (oral solution) contains 250 mg /5 ml, which is a red-orange solution. If the physician prescribes the syrup form, use the measuring cap provided with the bottle for the accuracy of the dose. Initially, lower doses are prescribed and are gradually increased to limit the side effects and achieve the complete benefits of the medication.
How Is Ethosuximide Absorbed in the Serum?
Oral intake of Ethosuximide gets completely absorbed in the gut. The half-life of the drug is usually 40 to 60 hours and is limited to 30 hours in children. Half-life is the time the body takes to reduce the active substance of the drug to half the concentration. It depends on how the drug is processed and is eliminated by the body. Because of the longer half-life, the drug takes several days to achieve a steady state in the body.
When Does Ethosuximide Toxicity Occur?
Ethosuximide toxicity occurs in individuals consuming more than the recommended doses prescribed by the physician, or the drug accumulates in the body without proper excretion. Therefore, there is a potential risk of fatal outcomes in case of overdosage of the drug, which may lead to depression of the central nervous system (CNS).
What Are the Signs and Symptoms of Ethosuximide Toxicity?
Toxic doses of Ethosuximide affect most organs, causing various adverse effects. The signs and symptoms of such toxicity are listed below:
Gastrointestinal System: Drug toxicity causes the following symptoms:
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Nausea.
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Vomiting.
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Stomach cramps.
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Loss of appetite.
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Stomach pain.
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Constipation or diarrhea.
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Indigestion.
Central Nervous System: It affects the central nervous system causing the following effects:
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Drowsiness.
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Mental confusion.
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Insomnia (lack of sleep).
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Increased libido (sex drive).
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Ataxia (poor muscle control).
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Depression.
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Delusion.
Skin: The symptoms are:
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Urticaria (skin rash).
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Hirsutism (excess hair around mouth and skin).
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Stevens-Johnson syndrome (skin disorder with painful rash).
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Skin peeling.
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Skin rash.
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Skin blisters (boils).
Blood: The symptoms are:
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Pancytopenia (deficiency of red blood cells, white blood cells, and platelets).
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Eosinophilia (increase in red blood cells).
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Leukopenia (decrease in white blood cells).
Genitourinary Tract:
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Hematuria ( presence of blood in urine).
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Vaginal bleeding.
Oral Cavity:
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Tongue swelling.
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Gum enlargement.
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Mouth sores.
Other Conditions Like:
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Headache.
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Dizziness.
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Fatigue or tiredness.
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Nose bleeds.
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Fever.
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Frequent infections.
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Easy bruising.
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Red or purple spots in the body.
How to Diagnose Ethosuximide Overdose and Toxicity?
The diagnosis of Ethosuximide overdose and toxicity is determined by a thorough examination of the history given by the patient, family members, or caregivers. The ingested doses and frequency of ingestion help the physician determine the severity of the condition. The clinical signs and symptoms further support the diagnosis of Ethosuximide overdose and toxicity.
How to Correct Ethosuximide Toxicity?
Ethosuximide toxicity can be treated in various ways after properly examining the clinical manifestations of the patient. Some of the measures to correct Ethosuximide toxicity are mentioned below:
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Supportive measures to improve the airway, breathing, and circulation.
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Gastric lavage (the process of cleaning out contents of the stomach).
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Monitoring the level of consciousness.
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Maintaining the vital signs.
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Intravenous fluid replenishments.
How to Prevent Ethosuximide Overdose and Toxicity?
Ethosuximide is an anticonvulsant that can be strictly used only after it has been prescribed by the health care professional. It has to be consumed in the form and dose prescribed by the physician to avoid toxicity. Ethosuximide toxicity causes mental disturbances like drowsiness, confusion, and insomnia. Hence, family members and caretakers are advised to keep an eye post drug administration and are requested to immediately report to their respective healthcare professionals if they suspect any toxicity.
Conclusion:
Ethosuximide is an anticonvulsant drug that helps limit convulsions or seizures. Overdosage of the drug can result in toxicity. Sudden withdrawal of the drug is not advised as it may cause a recurrence of the symptoms or worsen the existing condition. Following the instructions and recommended doses prescribed by the physician stringently helps minimize the symptoms and improves the quality of life.
